ANS-CVS 2 Flashcards
Example of muscarinic receptors agonist
- pilocarpine (use as eye drop to treat glaucoma)2. bethanechol
Example of muscarinic receptors antagonist
Atropine (treat bradycardia)hyoscine
Indirect acting of cholinergic agonist
Action of cholinesterase inhibitors (inhibit Ach catabolism)
Types of cholinesterase inhibitors
- Carbamates (physostigmine, neostigmine)2. Phosphates (isofluorophate)
Two type of cholinergic agonist
- Choline esters (Ach, bethanechol)2. Alkaloids (pilocarpine)
What are the effects produced by muscarinic agonists?
Parasympathetic-like effects.1. Smooth muscle (M1) - Increase GI peristaltic activity2. Cardiovascular (M2) - Cardiac slowing, decrease c. output3. Eye (M3) - Contraction of ciliary muscle4. Secretions (M3) - Stimulation of exocrine glands, sweating, lacrimation, salivation and bronchial secretion.
what is glaucoma?
increase intraocular pressure due to increase aqueous fluid production and decreased its trabecular outflow.
Effects produced by muscarinic antagonists
Sympathetic-like effects1. Smooth muscle (M1) - Bronchial, biliary & urinary tract SM relax. GI transit is inhibited2. Cardiovascular (M2) - Tachycardia3. Eye (M3) - Dilation of the pupil and relaxation of ciliary muscle4. Secrettions (M3) - Inhibition of secretions; dry mouth, bronchial mucociliary clearance is inhibited.
Therapeutic uses of muscarinic antagonists
- GI actions: - treat hyermotility and spasm associated with GI disease (IBS) - Dicycloverine2. Resp. actions: - Treatment of COPD and acute asthma; as bronchodilator - Ipratropium3. Urinary tract: - relieve muscle spasm accompanying infection4. CVS actions: - Treating bradycardia associated with MI - Atropine 5. Overactive bladder: - Reduce spontaneous myocyte activity - decrease frequency and intensity of detrusor activity - M3 receptor antagonists - Adverse reaction - dry mouth, constipation, blurred vision, cardiac arrhythmia
Botulinum toxin..
- Botulinum toxin A (BTX-A) most potent and have a longer duration of action- Administered and act in a site specific manner
Type of neuromuscular blocking drugs
- Non depolarising: Block Ach receptors2. Depolarising: Agonists at Ach receptors
Examples of competitive antagonists of Ach at mNicotinic receptor:
Tubocurarine analogues1. Mivacurium2. Atracurium3. Vecuronium4. Pancuronium
How depolarising agent act as neuromuscular blocking drugs?
- Sustained mNicotinic agonism at NMJ -> depolarisation block
Depolarising agent (suxamethonium) is contraindicated in..
- Neuropathies2. Myopathies (esp malignant hyperthermia)3. Burns/severe trauma (hyperkalaemia -> risk of arrhythmia)
Example of AchE inhibitors (indirect cholinergic agonist)
- Short-acting quaternary alcohols: - e.g. edrophonium - Bind to anionic site -> prevent Ach access - Readily reversible -> brief action - Used in diagnosis of myasthenia gravis2. Medium acting Carbamyl esters - e.g. neostigmine, physostigmine (longer acting) - Carbamyl transfer to anionic site, then slow hydrolysis - As reversal of NMJ block, myasthenia treatment - Also Alzheimer’s (doneprezil, tacrine)3. Irreversible block - e.g. echothiopate (eye drop for glaucoma), dyflos, melathion - Phosphorylate ser203 at active site; stable bond so long lasting - Reversible within first 1-2 hours using pralidoxome
Example of direct acting adrenoreceptor agonists
- dobutamine2. epinephrine3. phenylephrine
Example of beta blockers
- Atenolol2. Propanolol
dobutamine
- direct adrenoceptor agonist2. Effects: - Cardiac stimulation (B1) - Vasodilation (B2)3. clinical use: - cardiogenic shock - acute heart failure - cardiac stimulation during heart surgery4. side effect - arrhythmias
epinephrine
- Effects: - Vasoconstriction and increase BP (a1) - Cardiac stimulation (B1) - Bronchodilation (B2)2. Side effects: - Hypertension - Vasoconstriction - Arrhythmias
Example of indirect acting adrenoreceptor agonists
- amphetamine2. cocaine3. ephedrine
cocaine
- Effects: - Inhibition of norepinephrine reuptake2. Side effects: - hypertension - cardiac damage - necrosis of nasal mucosa (abuse)
ephedrine
- Effects: - vasoconstriction (a1)2. Clinical use - nasal decongestion3. Side effects: - hypertension - tachycardia - insomnia
phenylephrine
- Effects: - Vasoconstriction, increase BP, mydriasis (a1)2. Side effects: - Bradycardia - Hypertension
amphetamine
- Effects: - increase norepinephrine release 2. Side effects: - hypertension - tachycardia - dependence
Examples of a-blockers
- Prazosin 2. Phentolamine
prazosin
- MOA: competitive a1-blocker2. Effects: - vasodilation - decrease vascular resistance and BP - relax bladder neck and prostate3. Clinical use: hypertension4. Side effects: - hypotension - tachycardia - nasal congestion
phentolamine
- MOA: competitive a1 and a2 blocker2. Effects: - Vasodilation - Decrease vascular resistance and BP3. Side effects: - Hypotension - tachycardia - nasal congestion
atenolol
- MOA: B1-blocker2. Effects: - decrease cardiac rate, output, AV node conduction & O2 demand - decrease blood pressure3. Clinical use: hypertension, angina, acute MI, arrhythmia4. Side effects: - Cardiac failure - Bronchoconstriction
propanolol
- MOA: B1 and B2 blocker2. Effects: - decrease cardiac ratem otput, AV node conduction & O2 demand - decrease blood pressure3. Clinical use: hypertension, angina, arrhythmia, acute MI4. Side effects: - cardiac failure - bronchoconstriction
Example a & b blockers
Cervedilol
carvedilol
- MOA: - B1 and B2 blocker - a1 blocker2. Effects: - Vasodilation - decrease heart rate and BP in patient with hypertension - increase cardiac output in patient with heart failure
