Cholinergic Antagonist Flashcards
Scopolamine
Isopto Hyoscine/ transderm scop. Also a tertiary I mean plant alkaloid produces Peru Friel effect similar to those of atropine although has greater action on CNS. Anti-motion sickness produces sedation but at higher doses produces excitement
Atropine
Isopto atropine. Tertiary a mean belladonna alkaloid with high affinity for muscarinic receptors. Binds competitively and prevents ACH from binding to sites. Block muscarinic activity and I resulting in mydriasis. Reduce his activity in G.I. tract low doses is a slight decrease in heart rate at higher doses causes increase in heart rate. Produces dryness of mouth
Ipatropium and tiotropium
Atrovent, spiriva handi haler. Quaternary derivatives of atropine these agents are use for bronchodilators. For treatment of bronchospasm associated with COPD. Tiotropium has the advantage of one daily dose
Tropicamide and cyclopentolate
Midryacyl/tropicacyl, ak-pentolate/cyclogyl. Ophthalmic solution for my dryasis and cycloplegia.
Benzotropine and trihexyphenidyl
Cogentin,artane. Parkinson’s disease
Darfenacin,fesoterodine,oxybutnin,solifenacin,tolterodine,trospiumchloride
Enablex,toviaz,ditropan,vesicare,detrol,sanctuary. Synthetic atropine like drugs used to treat overactive bladder blocks muscarinic receptors in bladder
Ganglionic blockers
Block nicotinic receptors of both parasympathetic and sympathetic autonomic ganglia some also block I am channels show no selectivity toward parasympathetic or sympathetic ganglia. not effective as neuromuscular antagonist
Nicotine
Depolarizes ganglia resulting in stimulation then paralysis of ganglia.
Neuromuscular blocking agents
Block cholinergic transmission between motor nerve endings and nicotinic receptors on skeletal muscle. Act as either antagonists (nondepolarizing type) Or as agonist (depolarizing type).
Neuromuscular blockers (non de polarizing competitive drugs)
Cisatracurium(nimbex), pancuronium (pavulon), rocuronium (zemuron), vecoronium.
Nondepolarizing competitive blockers drug interactions cholineesterase inhibitors
Choline esterase inhibitor’s reverse action of nondepolarizing neuromuscular blockers. However with increased dosage cholinesterase inhibitor’s can cause a depolarizing block as a result of elevated acetylcholine concentrations.
Halogenated hydrocarbon anesthetics
Drugs like desflurane enhance neuromuscular blockade by stabilizing NMJ
Aminoglycoside antibiotics
Gentamicin and tobramycin inhibit acetylcholine release from cholinergic nerves by competing with calcium ions.
Calcium channel blocker’s
Increase neuromuscular blockade of competitive blockers
Depolarizing neuromuscular blocking agents
People arrive plasma membrane of muscle fiber similar to acetylcholine. However these agents are more resistant to degradation by acetylcholine esterase. Succinylcholine is only depolarizing muscle relaxant used today.
Succinylcholine
Anectine, quelicin. Attaches to nicotinic receptor and Acts like acetylcholine to depolarize Junction. Remains in synaptic little longer than acetylcholine. Useful for endotracheal intubation
glycopyrrolate
robinul
propantheline
hyperhydrosis
trimethophan
arfonad. ganglionic blocker (only one)
typical dose for atropine
.4-1.0mg For bradycardia, repeat q 3-5 minutes up to 3X
robinul dose
.2-.6 mg
how do we use these drugs
Patients with (advanced) heart disease often have increased parasympathetic tone (what does that do?) -Used most commonly for symptomatic bradycardia (what’s this?), pulseless electrical activity/electromechanical dissociation (what’s this?), and AV block (what’s this?)
side effects of antimuscarinics
tachycardia,dry mouth,
What are the effects of ganglionic blockers?”
PROFOUND hypotension via loss of sympathetic tone to the vasculature and histamine release.
- Predictably…Negative chronotrope, negative inotrope (with no reflex tachycardia…why?)
- Profound constipation
doses for trimethophan (arfonad)
Given IV
- Very short duration of action (5-15 mins) -Typical adult dose:
- 1.0-3.0 mg bolus -0.5-6.0 mg/min
therapeutic uses of neuromuscular blockers
Used extensively in surgery to prevent patient movement.
• Does NOT sedate, tranquilize, or anesthetize the patient!!!!
Depolarizing Neuromuscular Blocker Logic
phase 1:membrane depolarizes which causes transient contractions, followed by flaccid paralysis
phase 2:membrane repolarizes but is desensitized to ach
short acting less than 8 minutes
glycopyrrolate
robinul
