Flashcards in Pharmacology: Cholinoreceptor Blockers and Cholinesterase Regenerators Deck (35)
What class of drugs are pirenzepine and telenzepine?
They are both selective M1 inhibitors
What class of drugs are atropine, Benztropine, dicyclomine, glycopyrolate, Homatropine, cyclopentolate, tropicamide, Ipratropium, tiotropium, Oxybutynin, Scopolamine, Trospium?
They are non-selective antimuscarinic drug.
What is unique about the pharmacokinetics of atropine?
(1) Atropine is lipid soluble (tertiary amine groups) therefore it distributes to the CNS and other organs.
(2) It is eliminated partially by the liver and partially by unchanged excretion in the urine.
(3) duration of action of 4-8 hours except in the eye (72 hours)
What is the mechanism of action for muscarinic antagonists?
They act as competitive antagonists.
What is the effect of muscarinic blocking drugs on the CNS?
(2) anti motion sickness
What are the effects of muscarinic blockers on the eye?
Both block of M3
What are the effects of muscarinic blockers on the bronchi?
Bronchodilation (block of M3)
What is the effect of muscarinic blockers on the GI tract?
(2) slowed parastalsis
(3) reduced salivation
M1 and M3 blockade
What is the effect of muscarinic blockers on the genitourinary tract?
(1) relaxation of the bladder wall (detrusor)
(2) urine retention
M3 and possibly M1 blockade
What is the effect of muscarinic blockers on the heart?
(1) initial bradycardia
(2) secondary tachycardia
tachycardia from the block of M2 in the sinoatrial node
What is the effect of muscarinic blockers on blood vessels?
Block of dilation but only when muscarinic agonist is present. M3 blockade
What is the effect of muscarinic blockers on glands?
(1) reduction in salivation
(2) reduced lacrimation
(4) decreased gastric secretions
M1 and M3 blockade
What is the effect of muscarinic blockers on skeletal muscle?
What is musarinic blocker scopolamine used for used for clinically?
What are the muscarinic blockers commonly used to treat Parkinson's disease?
Benztropine, biperiden, triheyhphenidyl.
Theses are typically second line drugs after levodopa.
What muscarinic blockers are used to cause mydriasis?
What are the muscarinic blockers tiotropium and Ipratropium used for?
They promote bronchodilation in asthma or COPD.
What GI ailment can be treated with the selective M1 antagonist Prinzepine?
Prinzepine can be used for peptic ulcer (available in Europe)
What are Oxybutynin and tolterodine used for?
To reduce urgency and bladder spasms and urgency.
What class of drugs are Darifenacin, Fesoterodine, Solifenacin, tolterodine?
Muscarinic antagonists with a modest selectivity for M3 receptors.
What are Darifenacin, Fesoterodine, Solifenacin, and tolterodine used for?
urinary urgency and incontinence.
What are some predictable toxicities of muscarinic blockers?
(1) atropine fever (lack of sweating)(lethal in children and infants)
(2) lack of salivation and lacrimation
(4) angle closure glaucoma (elderly)
(5) urinary retention
(6) constipation and blurred vision.
What are some unpredicatable CNS side effects of muscarinic blockers?
(3) delirium or hallucinations
What are the adverse cardiovascular effects of muscarinic blockers?
(1) dilation of cutraneous vessels (red as a beet)
(2) Intraventricular conduction blockade.
What are the contraindications for muscarinic blockers?
(1) infants (hyperthermia)
(2) patients with glaucoma
(3) Men with prostatic hyperplasia.
What are the two principle classifications of nicotinic antagonists?
(1) ganglion blocking
(2) neuromuscular blocking
What is the mechanism of action for the ganglionic blockers?
They are competitive antagonists of the nicotinic receptors although some may also block the ion channel itself.
To what class of drugs do Hexamethonium, Trimethaphan, and mecamylamine belong to?
The are anti-nicotinic ganglion blockers.
For what was hexamethonium used?
hexamethonium was used as a selective Nn blocker for the treatment of hypertension. It is rarely used anymore because it blocks both sympathetic and parasympathetic ganglionic receptors. severe side effects.