B.4 Muscarinic receptor blocking drugs Flashcards
other names for cholinoceptor blockers
cholinergic antagonists
muscarinic antagonists
parasympatholytics
list the muscarinic antagonists
tropins: Atropine scopolamine Butyl-scopolamine Benztropine Ipratropium Tiotropium non-tropins: Cyclopentolate procyclidine solifenacin oxybutynin Tolterodine
list non-selective Muscarinic antagonists
Atropine cyclopentolate scopolamine Butyl-scopolamine procyclidine Benztropine
Adverse effects of muscarinic antagonists
opposite of "DUMBBELSS": ↓ secretions (salivary, sweat) Mydriasis, cycloplegia--> blurred vision glaucoma exacerbation hyperthermia ( with vasodilation)--> redness tachycardia CNS effect (sedation, hallucination) Urinary retention Constipation bronchodilation inhibit gastric secretion
duration of action of Atropine
2-4 hours
*mydriasis effect may persist for 8 days
list muscarinic antagonists that enter the CNS (lipid soluble)
atropine scopolamine procyclidine benztropine Trihexyphenidyl
indications for atropine
- mydriatic and cycloplegic agent- Opthalmology
- antispasmodic, antisecretory, antidiarrheal
- Reverse AV block (1st degree)
- Bradyarrhythmia (IV administration)
- Antidote for AchE inhibitor toxicity -Neostigmine, OPS
when should we avoid giving atropin and why?
in kids- sympatholytic effect, inhibits sweating –> skin is dry–> no heat evaporation mechanism–> Temperature ↑
how is cyclopentolate given?
eye drops (short-acting)
indications for cyclopentolate
mydriatic and cycloplegic agent- opthalmology
inner eye inflammation (avoid fibrin formation on the iris)
what is scopolamine for?
motion sickness (transdermal patch) in high doses--> sedation
does Butyl-scopolamine have CNS effects?
no
what is Butyl-scopolamine for?
abdominal cramps, menstrual cramps
how are ipratropium and tiotropium given?
inhaled
what are ipratropium and tiotropium used for?
bronchodilators for asthma/ COPD
indications for procyclidine, benztropine, trihexyphenidyl
Parkinson disease (in combination with a dopamine antagonist) Extrapyramidal disorders (drug-induced)
indications for solifenacin, oxybutynin and Tolterodine
Bladder spasm (postoperative, neurogenic) Urinary incontinence
why is it better to give Tropicomide and not atropin for an eye examination?
only lasts a few hours
systemic indication for glycopyrrolate?
extensive salivation
what is Pralidoxime (2-PAM) and how is it given?
Cholinesterase regenerator
Antagonist of organophosphate (IV)
displaces the phosphate from the serine residue
when is Pralidoxime used?
as an antidote for OPS poisoning
give early as possible
why is it important to give Pralidoxime as early as possible?
when the OPS- AchE complex reaches “aging”, Pralidoxime can no longer reverse the effect
