Glaucoma Therapy Part I (Beta Blockers, Cholinergic Agonist, Adrenergic Agonists)
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23 terms
Terms | Definitions |
|---|---|
 What creates Aqueous Humor in the eye? | Ciliary body -Cell membrane of NONPIGMENTED Ciliary epithelium contain (Alpha and beta (mainly beta-2) adrenoreceptors, Carbonic Anhydrase, Sodium and Potassium activated ATPases) |
| Where is the aqueous drained? | 80% TM, 20% Uveoscleral Flow (interstitial space btw ciliary muscle and iris root) |
| Vascular theory of GL? | High IOP induce ischemia in prelaminar ONH> retinal ganglion cell death and axon loss |
| Mechanical Theory | Compression of axons at ONH> impedes axoplasm flow > apoptosis of ganglion cells. |
| What vehicle would be beneficial in GL meds? | Hydroxypropylmethylcellulose or Polyvinyl Alcohol -Prolongs contact time -Better penetration, less frequency dosaging, and less adverse effects *Gels, Susp, Ocular inserts |
| Ocular Hypotensive Agents | -Beta Blockers, Cholinergic Agonist, Adrenergic Agonits, Carbonic Anhydrase Inhibitors, PG Family, Hyperosmotic Agents |
| Beta Blockers | *ISA: Exert some "Intrinsic Sympathomimetic Activity", thus although blocking, results in still slight stimulation of beta receptors. -Nonselective, DECREASE IOP by 25% -Dosage QD *BEST TIME IS IN THE MORNING! |
| ADR to Beta Blockers | Lethargy, weakness, Bronchospasm, Reduced pulmonary capacity, Confusion, Decreased libido, Anxiety, Depression, BC, Elevated Cholesterol levels, depression *Even thought these drugs are topical, take them seriously! |
| Absolute contraindications with taking Beta Blockers | 1) Asthma or hyper-reactive airway disease 2) Decompensated Congestive Heart Failure 3) Symptomatic Bradycardia or heart block 4) History of Fainting |
| Relative Contraindications | 1) Asymptomatic Bradycardia 2) Prefainting symptoms 3) Carotid Sinus hypersensitivity 4) Severe Mental Depression 5) Children and Infants |
| Systemic Beta Blockers | May lower IOP Examples: ANMP, Metoprolol |
| Timolol | Beta Blocker//0.25% and 0.50%. Relatively equivalent. (baby blue vs tan) *Maleate salt (more common) or Hemihydrate salt Common preservative: Benzalkonium Chloride vs. Timoptic XE: Benzododecinium Bromide **Nonselective beta blocker **Decreases aqueous production and does not inhibit aqueous flow during sleep! Decreases IOP by 30% ,No ISA, *QD, BID *Use: Primary and SEcondary GL. Also prophylactiv after Laser Iridotomy, capsulotomy, and CT surgery -used in combo and could be taken with safety with oral version. **Less EFFECT ON HR -> Gelrite Vechicle and Hemihydrate QD |
| Timoptic GFS | Gel forming Beta Blocker, Timolol |
| Nonpreservative Timolol? | Timoptic in Ocudose |
| Consensual Effect | Unique to Timolol "when the other eye is affected by the drug without the usage of the drops on that eye" |
| Escape | Unique to Timolol "Initial dramatic decrease> then a slight rise yet still better than s tx> plateau" Rapid: days to few weeks Acute vs Chronic Use |
| Drift | Unique to Timolol -Long term Effect (months to years of tx) -Slow rise in IOP and unsure why it occurs> require additional tx> usually change/switch B-blocker then maybe come back to timolol Other factors: change in disease state, noncompliance ~ 4 year study: 15% failure per year |
| Tachyphylaxis | Rapid and substantial loss of efficacy during first few doses |
| Short Term escape | -Not that rapid nor a substantial loss -After days to several weeks, IOP is not to pretreatment level, but stable with approximately 25% decrease from pretreatment level |
| Wash out period | Beta Blocker: Timolol -Significant ocular hypotensive effect up to 2 weeks after d/c > done to determine pressure OFF the drug or figure out the baseline pressures -Takes longer for dark irises but usually takes only a couple of days since there is still residual drugs ~ Similar for levobunolol |
| Ocular ADR to Timolol | Allergic REaction, stinging, corneal anesthesia (low amont B-blockers), SPK, Dry eye sx |
| Systemic ADR to Timolol *** | 1) Cardiovascular: BC, Conduction arrhythmia, Hypotension, *Raynaud's phenomenon (when cold temp or strong emotions BLOCK blood flow to extremities, Fluid retention) 2) Pulmonary: Bronchoconstriction/bronchospasm, asthma, Dyspnea 3) CNS: Depression, Lethargy, weakness, fatigue, lightheadness, Amnesia, Confusion, HA, Migraine prophylaxis, Impotence, Insomnia, Hallucinations 4) GI: Diarrhea, Nausea 5) Others: Hypoglycemia |
| Levobunolol | Beta Blocker -Non Cardioselective Beta 1 and 2 blockade **Decrease in production in aqueous humor *Dosage QD and BID, Better drug to take QD than timolol since it has a longer 1/2 life*** -No ISA or local anesthetic activity -Metabolized by dihydrobunolol -Preservative: Benzalkonium Chloride 0.004% *Ditto with Timolol but has the C-Cap (tells how many drops they took) |
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