Ocular Pharm MT1
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350 terms
Terms | Definitions |
|---|---|
 Decisions for the provider/prescriber: | - choice of drug - route of drug administration - when to refer patient, if at all |
| T/F, the Review of Systems (ROS) is essential to the Medical History? | True |
| patients who have cardiovascular disease may have problems with what drugs? | - phenylephrine (raises blood pressure) and - beta blockers (slows heart rate) |
| Patients with respiratory dz may have complications with what drugs? | 1) ASA and NSAIDs (can decrease inflammation and block production of prostaglandins) 2) beta blockers (using a non-selective beta blocker can exacerbate asthma or COPD) 3) opiate narcotic analgestics (can depress the respiratory rate, causing cardiac arrest) |
| Patients with hyperthyroidism may have complications with which drugs? | phenylephrine--can causes vasoconstriction and cause arrythmia and raise bp! |
| Patients with diabetes may have complications with which drugs? | 1) hyperosmotic agents (i.e. mannitol can increase blood glucose level) 2) systemic corticosteroids --can increase blood glucose levels 3) mydriatic agents --can increase BGL 4) beta blockers --blocks beta cells which release insulin to absorb glucose |
| Patient with a CNS disorder may have complications with which drugs? | Beta blockers --can cause anxiety, confusion, disorientation, nervousness, insomnia, memory changes |
| Patients with affective mental disorders may have complications with which drugs? | phenylephrine--may cause dizziness, drowsiness, HA, nervousness, excitability and irritability |
| True or false: systemic drugs are discouraged during pregnancy unless absolutely necessary | TRUE |
| Which portions of the eye exam are best performed prior to drug use? | VA, pupils, refraction, binocular tests, tonometry, SLE/biomicroscopy, amplitudes, assessment of cardiovascular status |
| What are different types of ocular side effects from topical ophthalmic drugs? | Allergy/hypersensitivity Infection Toxicity Other (IOP or conjunctival change etc) |
| What are the common causes of an infection from a topical ophthalmic medication? | Contamination of the dropper tip. Educate proper disposal |
| What are common side effects of drug toxicity from topical ophthalmic drugs? | punctate keratitis, itching, burning, stinging caused by preservatives |
| What OSE can ophthalmic topical steroids cause? | increased IOP, cataracts |
| What OSE can topical anti-glaucoma meds cause? | conjunctival changes |
| What OSE does prolonged use of anesthetic drops cause? | corneal abrasions, infiltrate keratitis |
| What OSE can ointment cause? | temporary blurriness |
| Describe the route that drugs go through when they get absorbed through the conjunctival sac. | drug-->conjunctival sac-->conjunctival capillaries-->systemic circulation |
| Describe the route that drugs go through when they gets absorbed through the lacrimal drainage | 1) drug-->lacrimal drainage-->nasal mucosa/capillaries-->systemic circulation 2) drug-->lacrimal drainage-->pharynx-->GI tract-->systemic circulation |
| What are the side effects of beta blockers when used for glaucoma. | decrease in heart rate syncopy bronchospasm emotional and psychiatric changes |
| What are the side effects of using echothiophate when used for open angle glaucoma? | can cause apnea if given with succinylcholine |
| What are the side effects of pilocarpine for glaucoma? | Nausea/vomiting bradycardia and tremors |
| What are the side effects of cyclopentolate? | a cycloplegic agent--excessive use can cause hallucinations |
| What are the side effects of brimonidine? | used for open angle glaucoma can lead to dry mouth, fatigue, and lethargy |
| What are ways to reduce systemic drug absorption? | - Store out of reach of children - Wipe excess solution or ointment - Use lowest concentration/minimal dose - confirm doses before prescribing infrequently prescribed drugs - weigh benefits to adverse effects - consider use of manual occlusion (nasolacrimal) if necessary - recognize ADE when they occur, lacrimal occlusion, consult with PCP |
| What are the two groups who require special consideration by optometrists - when prescribing topical or oral meds? | - women who are pregnant or breastfeeding |
| T/F: Nearly all the therapeutic drugs administered to or taken by a pregnant woman can cross the placenta | TRUE |
| T/F: Topically applied drugs can affect the fetus | TRUE |
| What are the factors that contribute to the concentration of the drug in the fetus? | Major factors: - concentration of drug in mom - age of fetus - degree of placental development - drug size - lipid solubility - protein binding characteristics - drug ionization (pH) Other factors: - dose-related effects - drug's pharmacokinetic properties - potential maternal or fetal disease states - specific stage of pregnancy - timing of exposure - degree of exposure over time |
| What are teratogenic effects (effects on fetus) resulting in fetal malformations, related to? | Dose and time |
| When is the period of greatest risk for malformation to occur in the fetus? | First 3 months of gestation--but can also occur throughout the entire gestational period |
| The Pregnancy risk factor should only be considered as a.... | starting point in prescribing! |
| T/F, Studies conducted in humans cannot fully address all possible areas or types of human risk, including genetic differences in populations. | True |
| Does the FDA pregnancy risk factor address the safety of using the drug while breastfeeding? | NO |
| When prescribing drugs to breast feeding moms, what does the prescriber need to consider? | 1) gestational stage 2) more detailed information about risk 3) individual factors such as other medical conditions that the mother may have |
| What is the best use of the FDA pregnancy risk factor? | The optometrist should contact the physician and discuss the rating and the advisability of proceeding with the proposed therapy, given the patients stage of pregnancy and health |
| Pregnancy Risk Factor Category A | No evidence of risk in any trimester, possibility of fetal harm appears remote |
| Pregnancy Risk Factor Category B | No studies in animal studies or human women have shown and/or confirmed adverse effect |
| Pregnancy Risk Factor Category C | Should only be given if the benefit justifies the potential risk to the fetus |
| Pregnancy Risk Factor Category D | Positive evidence of human fetal risk, but benefits to pregnant women may be acceptable despite the risk (life-threatening situation) |
| Pregnancy Risk Factor Category X | Contraindicated in women who are or may become pregnant. Risk outweighs benefit. |
| Why is it difficult to draw conclusions about the safety of drugs absorption in breast milk, even though tests have been done in animals? | Human breast milk has a different composition than animals, so we cannot make an absolute conclusion of its safeness. |
| Drug concentration in breast milk can be affected by which drug characteristics? | 1) lipid solubility 2) protein binding and 3) degree of ionization |
| What are the two things that an OD must be advise to do when prescribing drugs to breastfeeding moms? | 1) analyze the risk to benefit assessment 2) seek advice from PCP who is caring for patient |
| Why is it important in doing a culture and sensitivity test on breast feeding patients? | Can confirm the prescribing therapy, and may help look for other anti-infective meds that could have better risk factors |
| What can the optometrist recommend to minimize systemic absorption when administering topical ophthalmic medications to pregnant women? | Nasolacrimal Occlusion (punctual plugs) Nasolacrimal compression for 3-5 min after instillation of drops |
| Diagnostic drugs (pregnancy category) | C (fluorescein, indocyanine green, phenylephrine) |
| Analgesic drugs (pregnancy category) | C (proparacaine and tetracaine) B (lidocaine) Tetracaine and Lidocaine compatible with breastfeeding |
| Cycloplegic (pregnancy category) | C (atropine, homatropine, cyclopentolate, tropicamide) Atropine and Homatropine compatible with breastfeeding |
| Ocular decongestants (pregnancy category) | C (Naphazoline, Oxymethazoline, phenylephrine, Tetrahydrozoline) |
| Ocular Anti-histamines and Mast cell stabilizers (pregnancy category) | B (Cromolyn, Lodoxamide, emedastine, nedocromil) C (Azelastine, Pemirolast, olopatadine, ketotifen, epinastine) |
| Corticosteroids (pregnancy category) | C (Dexamethazone, difluprednate, flurometholone, loteprednol, rimexolone) |
| Bromenfac (pregnancy category) | C |
| Flurbiprofen (pregnancy category) | B |
| Diclofenac (pregnancy category) | D |
| Nepafenac (pregnancy category) | C |
| Ketorolac (pregnancy category) | D compatible with breastfeeding |
| Cyclosporine (pregnancy category) | C |
| Dipivefrin (pregnancy category) | B |
| Apraclonidine (pregnancy category) | C |
| Brimonidine (pregnancy category) | B |
| Apraclonidine (pregnancy category) | C |
| Diprivefrin (pregnancy category) | B |
| Echothiophate (pregnancy category) | C |
| Pilocarpine (pregnancy category) | C |
| Beta blockers (pregnancy category) | C (-olol) Timolol compatible with breastfeeding |
| Calcium channel inhibitors (pregnancy category) | C (acetazolamide, brinzolamide, dorzolamide, methazolamide) Acetazolamide compatible with breastfeeding |
| Prostaglandins (pregnancy category) | C (latanoprost, bimatoprost, travoprost) |
| Anti-infectives (pregnancy category) | B (acyclovir, valacyclovir, famciclovir) C (trifluridine) |
| Aspirin (pregnancy category) | D |
| Ibuprofen (pregnancy category) | D compatible with breastfeeding |
| Acetaminophen (pregnancy category) | C compatible with breastfeeding |
| Naproxen (pregnancy category) | C compatible with breastfeeding |
| Codeine (pregnancy category) | C compatible with breastfeeding |
| Hydrocodone (pregnancy category) | C or D |
| -cyclovir drugs (pregnancy category) | B acyclovir and valacylovir compatible for breastfeeding |
| Trifluridine (pregnancy category) | C |
| Natamycin (pregnancy category) | C |
| Penicillins (pregnancy category) | B compatible with breastfeeding |
| Clindamycin (pregnancy category) | B compatible with breastfeeding |
| Bacitracin (pregnancy category) | C |
| Sulfonamides (pregnancy category) | C |
| Cephalosporins (pregnancy category) | B (cefadroxil, cefprozil, cefuroxime, cephalexin) compatible with breastfeeding |
| Fluroquinolones (pregnancy category) | C (-oxacin) Ciprofloxacin and Ofloxacin compatible with breastfeeding |
| Azithromycin (pregnancy category) | B |
| Clarithromycin (pregnancy category) | C |
| Erythromycin (pregnancy category) | B (Excluding erythromycin estolate) compatible with breastfeeding |
| Aminoglycosides (pregnancy category) | C (gentamicin, tobramycin, neomycin) Gentamicin compatible with breastfeeding |
| Tetracyclines (pregnancy category) | D (classified as compatible with breastfeeding??) |
| What form of Erythromycin should NOT be prescribed to pregnant patients? | Erythromycin Estolate (also not compatible with breastfeeding) |
| True or false: Young Clark's rule can be used for pediatric dose calculations | FALSE, because the calculations are based on age and assumptions about weight vs. adult doses |
| What is the most accurate method to access the dosage for children? | Calculated using: - the body surface area --->height and weight - Pharmokogenetics--based on serum concentration in the child - Area under the curve - (body surface area nomogram) |
| What are the options when determining dosage to children? | 1) look at manufacturer dose recommendations on package insert 2) call physician 3) call pharmacists 4) call drug center 5) use ointments vs. drops |
| Why are geriatric patient more at risk for more ADE? | 1) they have more systemic diseases 2) are on a lot of drugs - multiple drug therapy (more important) |
| On average, what is the number of drugs an 85 y.o. is taking? | 11.5 |
| What are the things you should be concerned about when prescribing to the elderly? | 1) have diminished lid turgor (dry eyes risk) 2) lid laxity/ectropion (increase retention time of drugs, can have preservative build up in conj sac, exacerbate drug effect and cause toxicity) 3) cognitive difficulties 4) hearing impairment 5) socioeconomic factors 6) arthritis and tremors (diminished dexterity) 7) age related dose adjustment 8) Polypharmacy - patient taking numerous drugs |
| What are the types of teaching devices to help with compliance in the elderly population? | 1) dosage charts and calendars 2) teaching care givers 3) color coding and markers 4) medication regimen cards |
| What should be the minimum font size for patients with no visual impairment? | 12 |
| What kind of font do you use with visually impaired patients? | San Serif (22 or 24) font |
| What are the things you need to do with patients who are visually impaired? | 1) large font 2) demonstrate techniques, guided practice 3) make sure they understand your recommendations 4) use aids (magnifier, small light source) |
| What are the things you need to do with patients who are hearing impaired? | - Provide printed information - Demonstrate techniques and give guided practice - Have sign language charts with medical information and terminology in the office |
| What are the things you need to do with patients who are cognitively impaired? | - Provide instructions to caregiver and make sure that they understand. - Demonstrate techniques, guided practice - Extra time may be needed on these patients during exams. |
| Pharmacokinetics | Distinct factors and processes whereby drugs are absorbed and distributed in the body, biotransformed, metabolized, and excreted from the body |
| What does drug absorption depend on? | 1) molecular property of the drug (small, hypo/lypophillic drugs) 2) viscosity of drug vehicle (drugs that are suspended in gel sits in gel longer and lasts longer) 3) functional status of the tissue that forms a barrier to penetration (aqueous and lens) - aphakic patients will absorb drugs faster because they have no lens (barrier) |
| What can help predict the drug distribution over time and bioavailability of the drug at the desired target? | Interrelationships of the compartments and barriers of the eye |
| Lipid molecules that are composed of ____molecular weight and ionized/nonionized pass through plasma membranes better. | smaller, not ionized |
| How does the body prevent accumulation of drugs to the point of toxicity? | Drugs are inactivated, metabolized, and excreted. |
| T/F some drugs can be excreted in unchanged form. | TRUE |
| T/F some drug metabolites may be MORE or LESS active than the parent drug. | TRUE |
| Tissue types of the eye? | - Smooth musculature - Striated musculature - Different simple and mucoid epithelia - Connective tissues - Sympathetic nerves - Parasympathetic nerves - retina |
| How is it that the eye allows drug to be passed through without high absorption into the systemic system? | The front surface of the eye is avascular --which enables direct route for drug penetration without a high degree of drug absorption into the systemic circulation |
| Describe the outermost tear layer and its function. | - Oily lipid monolayer, produced by meibomian glands - Stabilizes the surface of the aqueous layer and retards evaporation. - Saline can flush away the lipid layer and increase evaporation |
| Describe the center tear layer | Aqueous phase, 95% of total volume, approx. 7 microliters thick. thins at each blink. |
| What is the average healthy TBUT? | 25-30 seconds |
| Describe the inner (basal) layer. | Composed of glycoprotein and mucin (secreted by goblet cells), a thin hydrophilic coating that covers the cornea and conj |
| What kinds of proteins do tears contain? | lysozymes, lactoferrins, gamma gobulins and other immune factors |
| What supplies the oxygen requirements of the corneal epithelium? | tears |
| what is the tear pH? | 7.4 |
| What is the normal tear volume? | 8-10mcl |
| what is the normal tear flow? | .5-22mcl per minute |
| What is the major site of absorption for ophthalmic topical meds? | cornea |
| The corneal epithelium is ____ cell-layers thick and has ___ layers. | 5-10 cell layers thick 3 layers |
| How do lipid soluble drugs get through the epithelium? | through the tight junctions (zona occludens). Zona occludens also repels hydrophilic drugs such as sodium fluorescein. |
| Ionization (increases/decreases) lipid solubility and (increases/decreases) water solubility. | Decreases, increases. |
| What does the rate of release of drug from the epithelium depend on? | - the drug's tendency to re-enter the aqueous phase. - A drug that is highly lipophilic has a longer half life and stays in the epithelium longer. - drugs need to be hydrophilic and lipophilic to effectively penetrate the cornea |
| What is the major functional barrier to ocular penetration? | the cornea |
| What is the most significant storage depot for drugs that partition into lipid media? | Corneal epithelium |
| How are drugs stored in the corneal stroma? (stroma = 90% of corneal thickness) | - Collagen slows diffusion and stores hydrophilic drugs. - Keratocytes store lipophilic drugs. |
| Why isn't the corneal ENDOTHELIUM a major reservoir for storing drugs? | - The endothelium is thin and has small overall volume - No tight junctions - Has fluid pump |
| When fluorescein that is given PO or IV, where does it accumulate in the eye? | It accumulates in the stroma from the aqueous |
| What is the function of the iris? | adjust the amount of light and DOF |
| What kind of innervation does the sphincter have? | Cholinergic |
| What kind of innervation does the dilator have? | Adrenergic |
| What in the iris can act as a reservoir for drugs? | - Pigment granules can store lipophilic drugs--- but is reversible so can also release drugs over time. - Concentrations may need to be different for darker pigmented irises than for blue irises |
| Where do drugs enter and exit from the aqueous humor? | Enter from the bloodstream or cornea Exit via the blood or schlemm's canal |
| Which part of the ciliary body can store drugs? | the pigmented ciliary epithelium |
| How do systemic drugs enter the anterior and posterior chambers? | By passing through ciliary body vasculature and diffusing into the iris |
| T/F, the ciliary body contains the major ocular source of drug metabolizing enzymes that start drug breakdown and removal from the eye | True |
| How are conjugated drugs and metabolites removed from the ciliary body? | Through the uveal circulation blood flow |
| How are drugs absorbed in the lens | 1) liphophillic drugs are absorbed slowly through the lens 2) hydrophilic drugs absorb minimally through the lens (especially those with high MW) |
| What drug types can increase cataract formation? | Miotics, steroids, phenothiazines |
| What happens if the lens is removed? | The kinetic relationship between the aqueous and the vitreous changes, because a physiologic barrier is removed and rapid drug exchange can take place. |
| What is the blood-retinal barrier? | Tight junctions in the RPE that prevent hydrophilic drugs from being absorbed |
| How does glucose get transported into the retina? | It is actively transported from the blood to the retina ==>too much glucose can damage cells (lipophilic drugs can easily cross the blood-retinal barrier in either direction) |
| What are the drugs that can cause retinal toxicity? | Phenothiaziine, Digoxin, Quinine, Fluroquinolones, Sildenafil |
| Which drugs can cross through the retina and achieve concentrations in the vitreous/posterior segment? | Fluoroquinolones, Linezolid, Fluconazole, Voriconazole |
| What are the drugs that have toxic effects on the optic nerve tissue, resulting in optic neuritis? | Ethambutol, Isoniazid and Streptomycin, Digoxin and Sulfonamides |
| Parenteral doses are only effective with what type of drug? | A drug with low toxicity that can enter the eye at therapeutic concentrations Ex: endophthalmitis - an internal ocular infection that must |
| If a drug has high toxicity as a systemic medication, what are the other options? | it can be used as a topical drug on the eye or injected into the eye--> where it will be diluted by the blood stream to non-toxic levels |
| The blood stream is responsible for removing drugs and drug metabolites from the eye, what are the two circulatory pathways? | 1) retinal blood vessels--remove from the vitreous and retina by active transport a. cephalosporins and penicillins have short T1/2s in the vitreous because of this 2) uveal blood vessels--remove by bulk transport via iris and ciliary body |
| What parts of the eye are considered barriers and what are considered compartments? | Barriers: epithelium, lens Compartments: aqueous and vitreous, tear layer and cornea |
| What is a compartment? | A region of tissue or fluid through which a drug can diffuse and equilibriate with relative ease. Which tissues are compartments or barriers is influenced by the molecular properties of the drugs |
| What is a barrier? | A region of lower permeability or restricted diffusion that exists between compartments |
| What is Fick's law? | The rate of diffusion across a barrier is proportional to the concentration gradient btween the two compartments. When concentrations are equal, no additional drug penetrates |
| T/F, Drug absorption from the tears to cornea is similar to from the cornea to the aqueous humor, except that the aqueous humor gets the majority (a major proportion) of the drug from the corneal depot. | TRUE, occurs in a parallel fashion |
| T/F, Lipophilic drugs that are also water soluble will penetrate corneal epithelium easier than more hydrophilic drugs. | TRUE |
| What affects corneal absorption? | - Tear film concentration in the first 10-20 min of instillation - Other drugs - Preservatives - Infection - Inflammation - Neuronal control |
| Describe zero order kinetics. | When release of drug is constant over time and is independent of concentration present |
| Describe first order kinetics. | - The rate of the drug molecule movement is directly proportional to the concentration difference across the barrier - Most common situation in ocular drug movement - Rate of movement changes with time as the concentration differential changes |
| What is an example of a first order kinetic? | Passive diffusion over a non-saturated barrier |
| Prodrugs | Precursors of the active drug Metabolites can be active drug compounds derived from a prodrug. |
| Latanoprost and travoprost are examples of what? and what is the mechanism? | - They are examples of prodrugs - Their ester linked molecule gets cleaved off when it penetrates the cornea and then becomes active in the aqueous |
| How are active metabolites formed? | It is formed through the hepatic metabolic process as well as ocular enzymatic process |
| What is an example of an active metabolite? | Loteprednol (corticosteroid) this is an active metabolite of prednisone that is transformed by the eye into an inactive form that will have fewer side effects in the eye |
| What is bioavailability? | The amount of drug that is available at the receptor site |
| What is ED50? | The dose level that is needed to produce 50% of the maximum therapeutic effect |
| Describe the process of drug effectively binding to receptors. | - The amount of drug going to the receptor site depends on the passage through several compartments - There needs to be sufficient drugs bound the receptors - There must be a sufficient time that the drug and receptors be in contact |
| What are active ingredients? | Ingredients that give therapeutic or diagnostic effects |
| T/F, Products other than the active ingredients can affect drug absorption. | TRUE, and active ingredients can also affect uptake of other drugs |
| What factors can affect drug stability? | - Acidic drugs are more stable - contamination (can affect formulation) - heat (accelerate breakdown of drug-->keep in fridge) - oxidation |
| What is the osmolarity of blood? | 290mOsm (equivalent to 0.9% saline) |
| Due to drugs and preservative, the blood osmolarity is usually HYPOTONIC. What can be used to bring Osm back to physiological level? | Salts, buffers and sugars can be added to adjust for osmolarity |
| What are the reasons we put preservatives in drugs? | They help to prevent the growth of microorganisms |
| What are types of preservatives put into drugs? | - Benzalkonium chloride/benzethonium chloride - Chlorhexidine - mercurial component - chlorbutanol - parabens - stabilize oxychoro-complex and sodium perborate (oxidation) - EDTA |
| Benzalkonium chloride/benzethonium chloride (preservative) | - aka BAK or BAC. - Surfactant: charged molecules that block bacterial plasma membranes - can have toxic effect on tear film and epithelium |
| Chlorhexidine (preservative) | - Block microbes metabolism, alters corneal permeability less than BAK/BAC |
| Mercurial compounds ie. Thimerosal (preservative) | - blocks microbe metabolism - most effective in weak acidic solutions - patients can develop sensitivity and allergies |
| Chlorbutanol (preservative) | - in artificial tears, less effective, no allergic reactions - Often combined with EDTA |
| Parabens (preservative) | - blocks microbe metabolism - found in artificial tears - can cause allergies - unstable at high pH |
| Stabilized oxychoro-complex (Purite) and sodium perborate (oxidation) | Preservative in artificial tears Purite dissipates to water and NaCl with light exposure Sodium perborate converts to H2O2, then into water and O2 in eye |
| EDTA (preservative) | - antioxidant properties that delay deterioration of products by oxygen in the air - can cause contact dermatitis - assists thimerosal and BAC |
| What are drug vehicles? | Agents other than active drugs or preservatives added to formulations to provide proper: tonicity, buffering, and viscosity - complements drug action |
| Polyvinylpyrrolidine (PVP) | nonionic polymer with binding and detoxification properties - low systemic properties, no immune rejection characteristics - can support viscosity |
| Polyvinyl alcohol (PVA) | water soluble viscosity enhancer - commonly used at 1.4% concentration in ophthalmic preparations—Boards - non-irritating and can enhance healing of abraded corneal epithelium - useful in dry eye syndrome and corneal epithelial erosion |
| Hydroxypropyl methylcellulose (on last year's exam) | - viscosicty enhancer - can prolong tear film wetting time (long acting AT) - can enhance ability of fluorescein and dexamethasone to penetrate cornea |
| Carboxymethylcellulose | similar properties to hydroxypropyl methylcellulose - greater adhesion to mucins than other viscosity vehicles - often in artificial tears |
| Sodium hyaluronate | - high viscosity in eye, and changes with motion of blinking - stabilizes tear film |
| Gel-forming systems | using larger molecules that demonstrate reversible phase changes - aqueous drop in eye reversibly gels on contact with precorneal tear film - enhance corneal penetration and prolong action of topical applications |
| Polyionic vehicles | vary in their lipophilic nature and in binding (not on exam) - enhance bioavailability of lipophilic durgs (ie: corticosteroids) |
| Polyacrylic acids | pseudoplastic properties where viscosity decreases with increasing shear rate (blinking) and ocular movement - good microadhesive and wetting properties |
| Ointment bases | mixtures of white petrolatum and liquid mineral oil with or without a water-miscible agent (ie: lanolin) - purpose: increase ocular contact time of applied drugs |
| Colloidal systems | prolong drug effect at site of action with less toxicity - common system is using liposomes (bioerodible/biocompaticle microscopic vesicles composed of lipid bilayers surrounding aq compartments) |
| Cyclodextrins | cyclic oligosacchardies that are water soluble and which can incorporate lipid-soluble drugs in their centers - used to improve solubility, stability of various compounds |
| What are 3 drug delivery systems into the eye? | 1) soft CTL - absorb drugs from solutions and release slowly into the eye 2) inserts 3) intraocular drug delivery system and intravitreal implants --treat viral infections |
| What is the most common route of ophthalmic drug administration? | Topical |
| What are the advantages of topically applied ophthalmic drugs? | Convenient, simple and non-invasive |
| Where do topically applied ophthalmic drugs clear through? | - diffuse through the circulatory system and via nasolacrimal duct - diffusion into blood occurs via bv of conjunctiva, episclera, intraocular structures and nasal mucosa vessels |
| Do topical drugs penetrate in useful concentrations to the posterior ocular structures? | NO, must use an oral drug for that. Minimal systemic absorption--except NSAIDs |
| How big is a drop size? | 25-50 mcl/drop average, sometimes up to 70mcl |
| What are advantages of topically applied ophthalmic solutions and suspensions? | - Ease of instillation - Little interference with vision - Few potential complications |
| What are the disadvantages for topically applied ophthalmic solutions and suspensions? | 1) brief contact time 2) contamination potential 3) ocular injury by dropper tip 4) imprecise amounts |
| What are sprays? | An alternative mode of ophthalmic administration Mydriatic or cycloplegic sprays can be applied to closed eyelids |
| What are the advantages of ointments? | - long contact time - easy to instill - non-invasive |
| What are the disadvantages of ointments? | - blurry vision - contact dermatitis - can be trapped under corneal ulcer flaps |
| Lid Scrubs | Application of solutions or other products directly to the lid margin |
| Advantages of gels? | - once daily administration - good patient compliance - little miosis during waking hours if applied at night |
| What are the disadvantages of gels? | - superficial corneal haze - weak ocular hypotensive effects - potential for SPK |
| Drug release from a CTL follows what kinetics? | First order--drug penetration through a thin lens delivers a greater proportion than through a thick lens |
| What are the factors that affect how drugs penetrate through a contact lens? | 1) pore size 2) concentration of drug 3) soak time 4) lens water content 5) size of drug molecule |
| How is a filter strip advantageous? | Long shelf life |
| Artificial tear insert | - Consists of a pellet of hydroxylpropyl cellulose placed in inferior conjunctival fornix - absorbs water and releases gel over eye surface - used for treating dry eye |
| What is a disadvantage of artificial tear insert? | Can cause blurring and foreign body sensation |
| When do we use continuous flow devices? | Large volume irrigation of the eye to dislodge foreign bodies, or irrigating chemical splashes and burns |
| What are the 2 medical conditions for which we use lid scrubs? | Seborrheic or infection blepharitis |
| Areas of administration by injection | - periocular/peribulbar - intracameral - intravitreal |
| T/F, Ophthalmic suspensions mix with tears less quickly than solutions and remain in the cul-de-sac longer | TRUE |
| What are the forms of a medical Rx? | Verbal, written, and electronic |
| When writing zeros in a prescription, what must be followed? | Use leading zeros (0.1) but NOT trailing zeros (1.0) |
| What abbreviations must be avoided in a prescription? | cc, qd, d |
| What information must be on a prescription? | - Patient name and address - Date - Medication Rxed - Directions to pharmacist (strength, quantity) - Directions to patient (Sig) - Refill info - Prescriber information (signature, prescriber address, license, license #s) |
| What is a schedule I drug? | Not commercially available, no approved indications |
| What is a schedule II drug? | strict limitations due to high abuse and dependency. CANNOT be refilled |
| What is a schedule III drug? | Significant abuse and dependence. Can be refilled up to 5X in 6months, though some states do not allow refills |
| What is a schedule IV drug? | lower abuse and dependency, some ODs can allow refills |
| What is a schedule V drug? | Low abuse and dependence. Most used to treat cough or diarrhea. none for ophthalmic use |
| For approval by the FDA, generic drugs must meet which criteria? | 1) same active ingredients 2) same bioequivalency and bioavailability 3) same pharmacologic and therapeutic activity 4) manufactured to FDA requirements 5) meet FDA requirements for stability, purity, strength and potency 6) labeled with the same claims, warnings and other info |
| What are the consequences of non-compliance with drugs? | 1) too much meds 2) too little meds 3) wrong reason 4) ADEs, increased risk of interactions 5) treatment failure 6) toxicity/overdose |
| What are the factors that contribute to non-compliance? | 1) complex regimen 2) can't understand regimen 3) don't know how to use it/indications 4) don't know the importance of medication 5) expensive |
| What is IMDA? | A method to support good patient compliance using layman's terms 1) introduction 2) mechanism 3) dosage 4) ask questions, ADE, anything else, make sure patient understands |
| What is the trade name for fluorescein sodium? | Ful-Glo® |
| What is the mechanism of sodium fluorescein? | Reveals defects in the corneal epithelium but does not stain tissues. |
| Indications for use of sodium fluorescein | CL fitting, GAT, diagnosis of corneal lesions, herpetic lesions. Also available for use intravenously in angiography |
| What are the ADEs of topical fluorescein solutions? | Risk for bacterial contaminations, nausea, HA, allergies, GI, distress, yellow skin, strong taste, discoloration of urine and skin, local irritation, stains CTL |
| Use caution of fluorescein among which patient groups? | allergies, hypersensitivity and asthma |
| What is the pregnancy category for sodium fluorescein? | C |
| What is the concentration of FulGlO strips? | 0.6mg strips |
| What is the generic name for Fluorexon? | Fluoresoft® |
| Compare the color of Fluorexon to sodium fluorescein | has a less fluorescent intensity |
| What does Fluorexon (Fluoresoft) stain? | Degenerated cells and mucus threads |
| Indications of Fluoresoft? | Aid to hydrogel (and other) CL fitting, GAT, corneal integrity, can be used for TBUT |
| What do you need to avoid use of when instilling Fluorexon? | Avoid use of hydrogen peroxide with CTL after instillation---because this will cause color to remain on the lens |
| What is the concentration of Fluoresoft? | 0.35% solution |
| How do you administer Fluoresoft? | You can place 1 drop onto the concave of a CTL, or 1 or 2 drop placed in the lower cul de sac, and 1 drop+1 drop of anesthetic for tonometry |
| What is the generic name for Indocyanine Green? | IC-Green® |
| What does indocyanine green contain? | Water soluble tricarbocyanine dye + sodium iodide |
| What are the uses of indocyanine green? | Dye for retinal and choroidal angiography, characterize neovascularization in ARMD |
| What is indocyanine contraindicated in | Iodine sensitivity - risk for anaphylaxis, allergic reactions |
| What are the formulations for powder and aqueous form of indocyanine? | - powder (25mg injection) - aqueous (10mL) |
| Which dye is only given intravenously? | Indocyanine green |
| What is the dose for the IV form of indocyanine green? | 40mg of dye in 2mL of solvent |
| What is the purpose of a lissamine green dye? | Stains dead or degenerated corneal and conj cells and precipitated mucous |
| Which dye is used as a diagnostic when the superficial corneal of conjunctival tissue may have been damaged? | Lissamine green |
| Which dye is used to dx dry eye conditions, corneal erosions and herpetic ulcers? | Lissamine green |
| What conditions will lissamine help dx? | dry eyes, corneal erosions, herpetic ulcers |
| What are the cautions of lissamine green? | NO ADE or irritations |
| What is the formulation of lissamine green? | 1.5mg strips |
| How do you administer lissamine green? | 1-2 drops of saline on strip |
| What will rose bengal stain? | Stains living cultured cells, dead cells and degenerated cells and mucous strands |
| What is rose bengal used for? | To evaluate dry eyes, herpetic keratitis, corneal abrasions and foreign bodies |
| What are the ADEs of rose bengal? | Irritation, discomfort, staining, flush eyes and wait 1hr before applying CTL |
| What is the formulation of rose Bengal? | 1.3 mg strips |
| Local anesthetics prevent generation and conduction of nerve impulses by: | - reducing sodium permeability - increasing threshold of nerve excitation - slowing propagation of nerve impulses - reducing the rate of AP rise |
| Describe the chemical structure of local anesthetics. | - Aromatic lipophilic portion (aromatic ring) - Intermediate alkyl chain (links to aromatic group by ester or amide) Most topically applied anesthetics = esters Most injectable anesthetic agents = amides - Hydrophilic amine group |
| Amides | Aniline derivatives metabolized in the liver and excreted primarily renally as metabolites with a small fraction of unchanged drug. - Lidocaine - Mepivacaine - Bupivacaine |
| Esters | PABA derivatives which are metabolized by hydrolysis of the ester linkage. - Cocaine - Proparacaine - Chloroprocaine - Tetracaine - Benoxinate (+fluorescein = Fluress®) |
| What are the two different groups of local anesthetics? | Esters and Amides |
| T/F, allergic reactions to local anesthetics occur almost exclusively to those with an amide linkage | FALSE, They occur in anesthetics with ester linkages |
| Indications of topical anesthetics | - tonometry - Removal of FB - suture removal - gonioscopy - nasolacrimal irrigation - prevent pain with probing or surgical procedures |
| Potential adverse effects of local anesthetics | - CNS stimulation (can be followed by CNS or respiratory depression) - Cardiovascular stimulation (can be followed by cardiovascular collapse) - Mydriasis - Nausea/Vomiting - Delirium - Convulsions - Allergic reactions (local and systemic) |
| Using local anesthetics with a vasoconstrictor such as epinephrine can cause what? | - Local hemostatis - Decreased systemic absorption of the anesthetic - Prolonged anesthetic duration of action |
| What are indications of Injectable local anesthetics? | - Used to produce facial block - Retrobulbar or peribulbar anesthesia - Eyelid infiltration |
| Injectable local anesthetics | - Bupivacaine HCL 0.75% - Lidocaine HCL 4% - Mepivacaine HCl 1% |
| T/F, with tetracaine, transient stinging, burning and conjunctival redness can occur | TRUE. Rare local reactions include lacrimation, photophobia, and chemosis. |
| T/F, A rare severe immediate-type allergic corneal reaction with acute diffuse epithelial keratitis and sloughing off of large areas of necrotic epithelium, diffuse stromal edema, and iritus has been reported with proparacaine and tetracaine. | TRUE |
| Topical local anesthetics | - Proparacaine HCL - Tetracaine HCL - Local Anesthetic Combinations Proparacaine HCl 0.5% dosages - Deep anesthesia: 1 gtt q5-10 min 5-7x - Removal of sutures: 1-2 gtt, 2-3 min before removal - Tonometry: 1-2 gtt immediately before - Removal of foreign bodies: 1-2 gtt prior to procedure |
| Tetracaine HCl dosage | 1-2gtt 0.5% |
| Local Anesthetic Combinations | - proparacaine HCl 0.5% + Fluorescein sodium 0.25% (Flucaine®) - Benoxinate HCl 0.4% + fluorescein sodium 0.25% (Fluress®, Flurox®) - Benoxinate HCl 0.4% + fluorexon disodium 0.35% (FluraSafe®) |
| Benoxinate/fluorescein deep ophthalmic anesthesia dosage | 2gtt OU q90seconds 3x |
| Mydriatics | Used for dilation (affects pupil size, accommodation, aqueous flow) Stimulates adrenergic division of autonomic nervous system |
| Cycloplegic Mydriatics | Anticholinergic drugs used in the eye to inhibit accommodation Used to treat uveitis/inflammatory conditions of uveal tract Inhibits the iris sphincter and ciliary body Produces pupillary dilation and cycloplegia Ex: Tropicamide, cyclopentolate, atropine, homatropine |
| Clinical uses of mydriatics | Pupillary dilation Testing for Horner's syndrome Ocular decongestant (constriction of ocular blood vessels) |
| Phenylephrine | A synthetic alpha-receptor sympathomimetic agonist structurally similar to epinephrine. Acts primarily on alpha-receptors A potent vasoconstrictor (conj blanching) and mydriatic agent Contracts dilator muscle and smooth muscle of conjunctival arterioles |
| Phenylephrine 0.12% indications | OTC concentration, ocular decongestant |
| Phenylephrine 0.12% response | Maximal response: 30-90 min |
| Phenylephrine 2.5% indications | - 2.5% = concentration recommended for infants and elderly - Pupillary dilation in uveitis - Open angle glaucoma - Prior to surgery - Funduscopy - refraction without cycloplegia - ocular decongestant and vasoconstrictor |
| Phenylephrine 2.5% response/recovery | Maximal response: 15-60 min Recovery time: 3 hours |
| Phenylephrine 10% indications | - used to break posterior synechiae - for peripheral corneal vessel vasoconstriction during LASIK - use should be minimized bc of greater risk of ocular, cardiovascular, and systemic side effects |
| Phenylephrine 10% response/recovery | Maximal response: 10-60 min Recovery time: 6 hrs |
| Phenylephrine contraindicated in: | Hypersensitivity Narrow angle glaucoma Narrow angle without glaucoma Low birth weight infants Elderly pts with severe ASCVD Cerebrovascular disease Pregnancy category C |
| 10% phenylephrine contraindicated in | Longstanding Type 1 Diabetes Orthostatic hypotension Advanced ASHD Pts with intraocular lens implant |
| Phenylephrine ADEs | Development of transient pigment floaters (elderly) Rebound miosis Cardiovascular effects (Palpitations, Cardiac arrhythmias, HT, Coronary occlusion, AMI) Intracranial/Subarachnoid bleeding Headache Sweating Dizziness Nervousness Drowsiness Increased blood glucose Weakness |
| Phenylephrine Topical effects | Blurred vision Mydriasis Increased redness Irritation Punctuate Keratitis Lacrimation Increased IOP |
| Phenylephrine + atropine interactions | Increased pressor effects of PE Increased potential for tachycardia |
| Phenylephrine + tricyclic antidepressants or MAOIs interactions | Contraindicated, increased cardiovascular effects |
| Phenylephrine dosage: Vasoconstriction/dilation | 1gtt after anesthetic |
| Phenylephrine dosage: Uveitis | To free recently formed posterior synechiae 1gtt 2.5% to upper cornea, hot compresses 5-10 min TID using 1gtt 1or2% atropine before/after hot compresses |
| Phenylephrine dosage: Glaucoma | 2.5% and 10% used in conjunction with miotics (open angle glaucoma) |
| Phenylephrine dosage: Surgery | 2.5% or 10% solution 30-60min before procedure: short-acting mydriasis for wide dilation |
| Phenylephrine dosage: Refraction | 2.5% solution used with homatropine, atropine, cyclopentolate or tropicamide Adults: 1gtt cycloplegic followed in 5 min by 1gtt 2.5% phenylephrine Followed in another 10 min by another gtt cycloplegic Refraction can begin in 50-60 min |
| Hydroxyamphetamine | An indirect-acting adrenergic agonist that is similar to norepinephrine (NE) in structure Works by release of NE from adrenergic nerve terminals and direct stimulation of alpha receptors Onset 15 min Max effect 60 min Duration 6 hours |
| Hydroxyamphetamine Indications | Mydriatic agent Cyclopegic effect in combination with Tropicamide Help distinguish between central or preganglionic sympathetic denervation in Horner's |
| Hydroxyamphetamine ADEs | Changes in IOP, BP Tachycardia Ventricular arrhythmia Can be safer than phenylephrine in Type 1 Diabetes |
| Hydroxyamphetamine Formulation/Dosage | 1% hydroxyamphetamine + 0.25% tropicamide (Paramyd®) Instill 1 gtt into eye, repeat as necessary |
| Contraindications of Cycloplegic mydriatics | Primary glaucoma Narrow anterior chamber angles Hypersensitivity to belladonna alkaloids/products Adhesions (synechiae) between the iris and lens Children with Hx of severe reaction to atropine or other anticholinergic |
| Atropine SO4 | 0.5-2% Mydriasis peak: 30-40 min Mydriasis recovery: 7-10 days Cycloplegia peak: 60-180 min Cycloplegia recovery: 6-12 days |
| Cyclopentolate HCl | 0.5-2% Mydriasis peak: 30-60 min Mydriasis recovery: 1 day Cycloplegia peak: 25-75 min Cycloplegia recovery: 0.25-1 day |
| Homatropine HBr | 2-5% Mydriasis peak: 40-60 min Mydriasis recovery: 1-3 days Cycloplegia peak: 30-60 min Cycloplegia recovery: 1-3 days |
| Scopolamine HBr | 0.25% Mydriasis peak: 20-30 min Mydriasis recovery: 3-7 days Cycloplegia peak: 30-60 min Cycloplegia recovery: 3-7 days |
| Tropicamide | 0.25 -1% Mydriasis peak: 20-40 min Mydriasis recovery: 0.25 days Cycloplegia peak: 20-35 min Cycloplegia recovery: 0.25 days |
| Cycloplegic Mydriatic ADEs | Local - Increased IOP - transient stinging/burning - irritation including lid reactions - redness/hyperemia/vascular congestion - follicular conjunctivitis - edema - dermatitis Systemic - dry mouth and skin - blurred vision - photophobia - tachycardia - headache - somnolence - visual hallucinations |
| psychotic reactions and behavioral disturbances may be caused by what cycloplegic mydriatics? | Tropicamide and Cyclopentolate |
| Cycloplegics must be used with great caution in which patients because they may cause a hyperactive pupillary response (especially atropine)? | Down's Syndrome and children with brain damage |
| What are toxic manifestations of anticholinergic drugs? | Skin rash drowsiness fever/hyperpyrexia vasodilation, urinary retention slowed GI motility decreased salivary and sweat gland production decreased secretion in pharynx, bronchi and nasal passages Severe: coma, medullary paralysis, death |
| Atropine/cyclopentolate/scopolamine/homatropine/tropicamide MOA | - Anticholinergic (parasympatholytic) drugs that block the responses of the sphincter muscle and muscle of the ciliary body to cholinergic stimulation. - Produces pupillary dilation (mydriasis) and paralysis of accommodation (cycloplegia) . - Cyclopentolate faster onset and shorter duration than atropine - Scopolamine greater anti-muscarinic potency than atropine - Tropicamide can reach higher concentration at muscarinic receptor sites, faster onset/shorter duration than other anticholinergics. |
| Indications for use of ______: mydriasis and cycloplegia in diagnostic procedures, and in acute inflammatory condition of the iris and uveal tract | Atropine, cyclopentolate, scopolamine, homatropine, tropicamide Scopolamine and homatropine also for pre/post operative uses |
| Atropine formulations/dosages | - Atropine sulfate ophthalmic ointment and solution (both 1%) - Adults uveitis: 1-2 gtt QID - Children uveitis: 1-2 gtt 0.5% TID - Refraction: 1-2 gtt 0.5% BID 1-3 days before exam - Ointment: in conjunctival sac TID |
| Cyclopentolate ADEs | - transient stinging/burning - increased IOP - More CNS effects than atropine (drowsiness, ataxia, disorientation, restlessness, emotional changes, hallucinations, incoherent speech) - avoid in open angle glaucoma or narrow angles -avoid in children, esp those with spastic paralysis or brain damage |
| Cyclopentolate formulations/dosages | - Cyclopentolate HCl ophthalmic solution (0.5%, 1%, 2%) Cyclogyl® - Adults: 1-2 gtt any % solution, repeat 5-10 min later if necessary - Children: 1-2 gtt 0.5% solution, repeat 5-10 min later if necessary - small infants: 1 gtt 0.5%, observe closely for at least 30 min |
| Scopolamine formulations/dosages | Scopolamine hydrobromide (Isopto Hyoscine®) 0.25% Uveitis: 1-2 gtt QID Refraction: 1-2 gtt 1hour before refraction |
| Scopolamine ADEs | Higher incidence CNS toxicity compared to atropine Not a drug of first choice for treatment of anterior uveal inflammation or cycloplegic refraction Drowsiness Restlessness Hallucinations Vomiting Confusion Higher incidence of idiosyncratic rxns than other |
| Homatropine Formulations/Dosages | Homatropine HBr opththalmic solution (2%, 5%) Isopto Homatropine® Uveitis: 1-2 gtt q3-4hr Refraction: 1-2 gtt, repeat in 5-10 min if needed Children: only use 2% strength |
| Tropicamide formulations/dosages | Tropicamide ophthalmic solution (0.5%, 1%) Mydral®, Tropicacyl® Refraction: 1-2 gtt, repeat in 5 min if needed Fundus exam: 1-2 gtt 0.5%, 15-20 min prior |
| Mydriatic combination products | Cyclomydril® Murocoll-2® Paramyd® |
| Cyclomydril® | 0.2% cyclopentolate HCl + 1% Phenylephrine HCl For mydriasis |
| Murocoll-2® | 0.3% Scopolamine HBr + 10% Phenylephrine HCl For mydriasis |
| Paramyd® | 0.25% tropicamide + 1% hydroxyamphetamine HBR For mydriasis |
| T/F, Allergic reactions in the eye most frequently affect the cornea and eyelids. | FALSE, they most frequently affect the conjunctiva. |
| There are 5 types of allergic reactions. Which two types are most often involved in ocular reactions? | I & IV |
| Describe Type I Hypersensitivity reactions. | - Occur when antigens are reintroduced in people with previous exposure. - After 1st exposure, B lymphocytes are activated and IgE makes mast cells more sensitive - When re-exposed, large quantities of inflamm mediators are released (prostaglandins, histamine, leukotrienes, eosinophile chemotactic factor) - Commonly occur in hay fever, allerg conjunctivitis, asthma, hymenoptera stings |
| What happens when histamine activates H1 receptors on blood vessels? | Vasodilation, leakage of fluid, tissue swelling |
| The immediate response of a Type I reaction starts ___ min after exposure and resolves after ___minutes. A late phase reaction my occur ___ hours later and last up to __ days. | 5-30 min, 30-60 min, 4-6 hours, 2 days |
| Signs and Symptoms of Type I reactions | Redness Swelling Itching Bronchoconstriction Rhinitis Tearing Headache Hives Sneezing Conjunctival hyperemia Anaphylactic shock |
| Describe Type IV Hypersensitivity reactions. | - Cell-mediated immune responses - Delayed hypersensitivity rxn involving T lymphocytes - after sensitization, delayed response takes 24 hrs, peaking at 48-72hrs |
| Where are H1 receptors located? | Heart bronchial smooth muscle CNS Mucous MB Gastric parietal cells BV of eye |
| Where are H2 receptors located? | Blood vessels Bronchial smooth muscle CNS WBCs Mast cells BV of eye |
| Ocular signs/symptoms caused by histamine | Itching, tearing, conjunctival and lid edema, dilation of conj vessels |
| Seasonal Allergic Conjunctivitis | Can result from many exogenous antigens Includes dust, pollen, smoke particles, environmental contaminants |
| Vernal Conjunctivitis | Seasonal disorder, peaks during warm months, Adolescent males Bilateral inflammation involving upper tarsal conj and sometimes limbal conj Papillary hypertrophy - gelatinous thickening of superior limbus Histamine level in tears high Itching, thick ropy discharge Photophobia if cornea involved Ptosis if signif. papillary |
| Atopic Keratoconjunctivitis | Caused by hereditary factors, not acquired hypersensitivity Usually a family hx or personal hx (hay fever or asthma common) Patches of thickened itchy dry skin Conjunctival chemosis and hyperemia Corneal involvement not common |
| Giant Papillary conjunctivitis | Conjunctival inflamm reaction to materials such as proteins on CL Papillary hypertrophy usually upper tarsal plate Lens thickness and diameter can be involved Lens instability, CL intolerance, itching, mucoid discharge can occur |
| T/F, Ocular decongestants should only be used for a short time because they can mask the symptoms of more serious conditions (bacterial etc) | TRUE |
| Decongestant contraindications | - Hypersensitivity - narrow angle glaucoma - narrow angles - discontinue prior to use of anesthetics which sensitize the myocardium to sympathomimetic activity |
| Phenylephrine 0.12% duration | 0.5-1.5 hr |
| Naphazoline 0.012%, 0.03%, 0.1% duration | 3-6 hrs 0.1% prescription only |
| Oxymetazoline 0.025% duration | 4-12 hrs |
| Tetrahydrozoline 0.05% duration | 1-6 hrs |
| Ocular sympathomimetic decongestant + general anesthetic agent (spec. anesthetic gases) | Sensitization of the myocardium to sympathomimetics |
| Ocular sympathomimetic decongestant + local anesthetic | Increased absorption of decongestant |
| Ocular sympathomimetic decongestant + beta blockers | Increased risk of systemic sympathomimetic ADEs |
| Ocular sympathomimetic decongestant + MAOIs | Exaggerated adrenergic effects can occur Allow 21-day interval after discontinuation of MAOI to minimize risk |
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