Question | Answer |
also referred to as: | parasympatholytics, muscarinic antagonists, anticholinergics, muscarinic blockade |
cholinergic blockers competitively block the actions of acetylcholine at | muscarinic receptors |
cardiovascular effects: | blockade of muscarinic receptors increases HR, can reduce the PR interval by blocking receptors in the AV node |
respiratory effects: | relaxes bronchial muscle , bronchodilation, decreases bronchial secretions |
exocrine gland effects: | very effective on salivary glands causing dry mouth, suppress thermoregulatory sweating[which can produce fevers in children] |
urinary and GI effects: | GI smooth muscle is affected from the stomach to the colon[visceral walls are relaxed and both tone and peristalsis are diminished]
smooth muscle of bladder and ureters is relaxed[can precipitate urinary retention] |
CNS effects: | mild CNS excitation, at high doses agitation, hallucinations, delirium
can partially correct parkinsonian tremor and EPS associated with antipsychotic drugs[especially if combined with a dopamine precursor] |
optic effects: | unopposed sympathetic dilator activity producing mydriasis[b/c papillary contrictor depends on muscarinic receptor stimulation]
cycloplegia[paralysis of the ciliary muscle]resulting in inability to accommodate near vision |
belladonna alkaloid group: | atropine, scopolamine |
quaternary group: | propantheline[Probanthine] |
others | benztropine[Cogentin], darifenacin[Enablex], fesoterodine[Toviaz], oxybutynin[Ditropan], solifenacin[Vesicare], tolterodine[Detrol], trihexyphenidyl[Trihexy], trospium[Sanctura] |
contraindicated in: | glaucoma, specially angle-closure b/c of mydriasis and cycloplegia |
cautious use in: | obstructive GI or GU tracts, older adults b/c of CNS effects of cholinergic blockers |
ADRs in cardiovascular: | tachycardia |
ADRs in respiratory: | tend to thicken and dry bronchial secretions |
ADRs in exocrine system: | anhidrosis[no sweating], xerostomia[dry mouth] |
ADRs in GI and GU: | constipation, urinary hesitancy nd retention, risk for UTIs, impotence |
ADRs on eye: | increased intraocular pressure, blurred vision, photophobia |
ADRs on CNS: | mild excitation to dizziness, confusion, CNS depression |
drugs that are not cholinergic blockers but have significant muscarinic blockade: | antihistamines, disopyramide[Norpace], quinidine, phenothiazine, antipsychotics, TCAs |
Parkinson's disease: | useful for control of tremor, early in course of tx, control of drooling
Trihex and Cogentin |
Tx of EPS | drug of choice for this: Cogentin, Trihex |
Tx for overactive bladder and urinary incontinence: | Enablex, Toviaz, Ditropan, Vesicare, Detrol, Sanctura
no cholinergic effects at the myoneural junction for any of these drugs |
oxybutynin[Ditropan] increases blood levels and bioavailability of | nitrofurantoin so different antibiotic should be chosen |
assessment for bladder outlet obstruction should be done prior to prescribing these drugs | b/c that contraindicates them |
prevention of N/V from motion sickness | scopolamine patch behind ear |
adjunct therapy in IBS and PUD: | atropine, dicyclomine[Bentyl], propantheline |
atropine poisoning in children s/s: | burning sensations in the mouth, difficulty in swallowing, rash, blurred vision, tachycardia, tachypnea, fever up to 109.8, muscle incoordination, seizure, respiratory paralysis, death |
antidote for atropine poisoning is: | physostigmine[Abrilirium, Isopto Eserine] |