How does a competitive antagonist effect an agonist?
- Shifts the curve down -reduces Vmax
How does a noncompetitive antagonist effect an agonist?
-Phase I (clinical tests) -Phase II -Phase III -PhaseIV (surveillance)
Name the steps in drug approval(4)?
In 4 half-lifes= (94%) T1/2 = (0.7x Vd)/CL
Steady state concentration is reached in __ number of half-lifes
-Constant AMOUNT eliminated per unit time. -Etoh & ASA
What is the definition of zero-order kinetics? Example?
CL= (rate of elimination of drug/ Plasma drug conc.)
What is the formula for Clearance (CL)
Vd= (Amt. of drug in body/ Plasma drug conc.)
What is the formula for Volume of distribution (Vd)
Ld= (CpxVd)/F Cp=plasma conc. F= Bioaval.
What is the loading dose formula?
Epinephirine(Alpha1,2 and Beta 1,2)
A 12yo patient was treated for a reaction to a bee sting, what drug provides the best coverage of sympathomimetic receptors?
A 57 yo heart failure pt develops cardiac decompensation, what drug will give you adequate perfusion of his kidneys as well as tx for his Hypotension
A fellow passenger on a Carnival cruise ship looks pale and diaphoretic, what antimuscarinic agent would you give them?
Atropine pts are suffering from Cholinestrase inhibitor poisining (Nerve gas/Organophosphate poisining)
A group of pts are rushed into the ER complaining of excessive sweating, tearing, salivation, HA, N and V, muscle twitching, difficulty breathing and diarrhea. What drug would be the most effective immediate tx
As an Anes you want to use a depolarizing neuromuscular blocking drug on your pt, what do you use
Prevents the release of Ca from SR of skeletal muscle
MOA of Succinylcholine
Centrally acting alpha agonist, thus causing a decrease in central adrenergic outflow, spairing renal blood flow
Clonidine is the preferred sym pathomimetic tx of HTN in pts with renal disease, why??
Indirect agonist, uptake inhibitor
Cocaine casues vasoconstriction and local anesthesia by what mechanism
Cocaine shares is mechanism of action with what antidepressant
Beta1 more than B2
Dobutamine used for the tx of shock acts on which receptors
No, it inhibits the release of Nor Epi
Guanethidine enhances the release of Norepi?
It acts presynaptically to increase NE release.
How does angiotensin II affect NE release?
Prevents the release of ACh, which results in muscle paralysis.
How does botulinum toxin result in respiratory arrest?
Prevents the release of calcium from the sarcoplasmic reticulum of skeletal muscle.
How does dantrolene work?
NE acts presynaptically on alpha-2 receptors to inhibit its own release. ACh also acts presynaptically through M1 receptors to inhibit NE release.
How does NE modulate its own release? What other neurotransmitter has this same effect?
Hemicholinium inhibits the transport of choline into the nerve, thus inhibiting formation of ACh.
How would hemicholinium treatment affect cholinergic neurons?
Give an antichloinesterase - neostigmine, edrophonium, etc
How would you reverse the effect of a neuromuscular blocking agent?
It would increase to ~ 100 beats/min. Both sympathetic and vagal stimulation would be knocked out, but the SA node has an intrinsic pace of 100 beats/min, which is normally checked by vagal stimulation.
If a patient is given hexamethonium, what would happen to his/her heart rate?
Stimulates beta adrenergic receptors
Isopoterenol was given to a patient with a developing AV block, why?
Binding to the presynaptic alpha 2 release modulating receptors
Norepi feedbacks and inhibits the presynaptic receptor by what mechanism
Blocks Norepi, but not Dopamine
Reserpine will block the syntheis of this drug and but not its precursor.
Amphetamine and Ephedrine
These drugs acts indirectly by releasing strored catecholamines in the presynaptic terminal
What anticholinesterase crosses the blood-brain-barrier?
What antimuscarinic agent is used in asthma and COPD?
What antimuscarinic drug is useful for the tx of asthma
Diarrhea, Urination, Miosis, Bronchospasm, Bradycardia, Excitation of skeletal muscle and CNS, Lacrimation, Sweating, and Salivation = DUMBBELS; also abdominal cramping
What are the classic symptoms of cholinesterase inhibitor poisoning (parathion or other organophosphates)?
Activates cholinergic receptors on bladder and bowel smooth muscle, alleviating post-op and neurogenic ileus and urinary retention.
What are the clinical indications for bethanechol?
Post-op and neurogenic ileus and urinary retention, myasthenia gravis, and reversal of neuromuscular junction blockade (post-op) through anticholinesterase activity.
What are the clinical indications for neostigmine?
narcolepsy, obesity, and attention deficit disorder (I wouldn't recommend this)