Basic Pharmacology Deck 2 Flashcards
What is the volume of distribution?
Dose / initial concentration (it is the apparent volume for a given drug)
What is the clearance rate?
elimination rate constant * volume of distribution.
How do you find the serum concentration after a single iv dose of medication at a given time t?
Exponential decline given by:
Ct = Co*e^-kt
where k is the elimination rate constant.
How does one calculate the steady state concentration of a constant iv infusion?
steady state is the administration rate divided by the clearance rate.
How do you calculate the appropriate loading dose to reach a given concentration?
D-loading = steady-state concentration * volume of distribution. (divide by bioavailability of giving PO)
What is the total body storage (TBS) of a drug?
1.44 * amount administered per elimination half-life.
What is bathanechol and what does it do?
AcCh Muscarinic agonist (AcCh derivative). (parasympathomimetic), stimulates GI tract and bladder. Relatively specific for M3 receptor subtype, so little effect on heart. Resistant to all cholinesterases.
What is muscarine and what does it do?
AcCh muscarinic receptor agonist (hence name of receptor). Found in poisonous mushrooms. Not used clinically.
What is pilocarpine and what does it do?
AcCh muscarinic agonist (parasympathomimetic). Naturally occuring alkaloid, used to treat dry mouth (xerostomia) and intraocular pressure in glaucoma. Increases saliva production and facilitates resorption of aqueous humor.
What is nicotine and what does it do?
AcCh nicotinic agonist, acts at sympathetic and parasympathetic ganglia, skeletal muscles, CNS. Causes release of epi from adrenal medulla and resultant CV effects.
What is physostigmine and what does it do?
AcCh agonist, binds AcCHesterase, preventing degredation of AcCh in synaptic cleft. Physostigmine is taken up in gut more readily than neostigmine because it doesn’t have a positive charge.
What is neostigmine and what does it do?
AcCh agonist, binds AcCHesterase, preventing degredation of AcCh in synaptic cleft. Known as a reversible carbonate. Used for atony of GI tract and bladder (same as pilocarpine).
What is atropine and what does it do?
muscarinic antagonist, (parasympatholytic) autonomic effects appear in following pattern as dose increases:
1) decreased salivation and sweating
2) pupil dilation
3) decreased gut motility
4) inhibition of gastric secretion.
Little or no central effect in clinical doses.
What is scopolamine and what does it do?
muscarinic antagonist (parasympatholytic). causes drowsiness, amnesia in clinical doses. Delivered via transdermal patch to prevent motion sickness.
What is hexamethonium and what does it do?
Nicotinic antagonist, binds only to ganglia nicotinic receptor subtype (doesn’t effect nicotinic skeletal muscle receptor).
What is the baroreflex?
neurons in the aortic arch and carotid sinus sense drops in BP and change output of autonomic system. Eg. if BP drops, it will increase cardiac output and peripheral resistance. Often involves compensatory effect after drug delivery.
Which type of cholinergic receptors display biphasic effects?
Nicotinic receptors (not muscarinic).