Cholinergic Antagonist Flashcards
Mechanism of action of cholinergic antagonists
Bind to receptors
Nicotinic selective cholinergic antagonists
Nicotine
Trimethaphan
Mecamylamine
Neuronmuscular blockers
Muscarinic selective cholinergic antagonists
Atropine
Ipratropium
Scopolamine
Muscarinic selective chol. antagonists in order of CNS distributions (low to high)
Ipratropium<Scopolamine
CHOl. Antagonists block which functions?
SLUD: Salivation Lacrimation Urination Defacation
medical uses of cholinergic antagonists
Ophthalmology Asthma COPD Cholinergic OD GI hypermotility/Urinary incontinence Motion Sickness Parkinsons
Mydriasis
Increase in pupil size due to radial muscle contraction (cholinergic antagonists)
Miosis
Reduction in pupil size due to circular muscle contraction (cholinergic agonists)
Accommodation
Contraction of ciliary muscle (near vision) = outflow of aqueous humor outflow by pulling trabecular meshwork –> reduce IOP (cholinergic agonists)
Cyclospasm
Excess accommodation caused by marked contraction of ciliary muscle (cholinergic agonists)
Cycloplegia
Weakening of contraction of ciliary muscle leading to a loss of accommodation
Drugs used to induce mydriasis in eye exams
Atropine
Phenylephrine
Atropine
Muscarinic receptor antagonist
Used to get mydriasis, cycloplegia (circular muscle, ciliary muscle)
Treat forms of GI hyper motility/incontinence
Counteract excess cholinergic muscarinic activity
Adverse side effects of Atropine
Blind, dry, red, hot, mad
Kids especially susceptible to thermogenic effects
Contraindications for Atropine
Glaucoma
Manifestations of asthma
Increased mucus Swelling of bronchial tube lining Bronchoconstriction Coughing Wheezing SOB
Drugs used in asthma patients
Epinephrine
B2 Adrinergic Agonists
Ipratropium
Diseases involved with COPD
Chronic bronchitis
Emphysema
Drugs used in COPD patients
Ipratropium
Epinephrine
B2 adrenergic receptor agonists
etc
Ipratropium
Competative muscarinic antagonist
TX: COPD, Asthma, Facilitate B2 Adrenergic agonist effects/those who cant tolerate them
MOA of Ipratropium
Antagonism of musc receptors in bronchiolar SM: BRONCHODILATION
Antagonism of musc receptors in bronchiolar sub mucosal glands: deacrease mucus secretion
Distribution of Ipratropium in CNS
LITTLE CNS penetration
Drug used in GI/Urinary disorders
Atropine
Drug used in motion sickness
Scopolamine
Scopolamine selectivity
Competative musc antagonist
Scopolamine indications
Prevent nausea/vomiting in motion sickness
Pre-anesthetic agent
high CNS
Manifestations of cholinergic OD
DUMBBELSS
unable to walk, chest tightness, voiding
Loss of consciousness, seizures, death
Drugs used to treat organophosphate poisoning/cholinergic OD
Atropine
Pralidoxime
Ganglionic blocker MOAs
block output of ANS at the ganglia by:
- competative/stabilizing (trimethephan & mecamylamine)
- depolarizing blockade (nicotine)
Trimethephan selectivity
Competitive, non-depolarizing nicotinic receptor antagonist
Trimethephan indications
RARE
Controlled reduction of BP during surgery
Treatment of hypertensive emergencies
Mechanism of Trimethephan
Block ganglionic nicotinic receptors –> vasodilation
Mecamylamine selectivity
Competitive, non-depolarizing nicotinic receptor antagonist
Mecamylamine indications
RARE
Management of mod-sev HTN
Nicotine anti-craving tx
Mechanism of Mecamylamine
Block ganglionic nicotinic receptors–> vasodilation
Nicotinic selectivity
Depolarizing nicotinic receptor antagonist
