Autonomics Flashcards
Botulinum toxin
prevent release of ACh
Degrades synaptobrevin (SNARE) and prevents vesicle fusion / exocytosis
Edrophonium
Reversible Anti-cholinesterase
Short duration of action; Useful for diagnosing Myasthenia gravis (MG) and Eaton Lambert
Neostigmine and Physostigmine
Longer duration of action; useful for treating MG; reversal of neuromuscular blockers
(Physostigmine crosses BBB – good for CNS e.g. atropine poisoning)
Hydrolysed by AChE so that a covalent bond forms increasing the ½ life of the AChE inhibition
Malathion
Irreversible anti-cholinesterase, toxic, commonly used in pesticides
Pilocarpine
Muscarinic Receptor Agonist
Used to treat glaucoma by activating receptors on circular muscles of eye causing miosis; drains aqueous humor – decreasing intraocular pressure
• Used to treat dry mouth in Sjogrens Syndrome
Methacholine
Muscarinic Receptor Agonist
3x more resistant to hydrolysis by AChE
• Possesses little affinity for nicotinic receptors
• Used in diagnosis of asthma
Bethanecol
Muscarinic Receptor Agonist
Almost completely selective for muscarinic receptors
• Agent of choice for promoting GI and urinary tract motility; assists in bladder emptying
• Particularly post-operative, post-partum and drug-related urine retention
Atropine
Muscarinic Receptor Antagonists
Poison found in certain plants
Competitive antagonists
• Allows sympathetic responses to predominate
•Atropine used clinicall to reduce all of the following: SLUDGE mnemonic S – Salivation L – Lacrimation U – Urination D – Diaphoresis (sweating) G – GIT motility E - Emesis
Succinylcholine
Neuromuscular Nicotinic Agonists
Depolarizing Neuromuscular Blocker. channel continuously open causing desensitizing of the receptor leading to paralysis.
Used to produce paralysis of pharyngeal muscles for intubation and ventilation (short procedures)
Side Effects and Adverse Reactions:
• Bradycardia, K+ release (from prolonged depolarization), prolonged paralysis; malignant hyperthermia
Pancuronium
Neuromuscular Nicotinic Antagonists
Prevents opening of receptors leading to paralysis.
Uses: Induction of muscle paralysis (flaccid) in surgery (long procedures) overcome by Ach
Side effects: Hypertension, apnea, bronchospasm, salivation, flushing and respiratory failure
Phenylephrine
Alpha 1 Agonist
Nasal decongestant; treatment of shock
Side effects: Hypertension
Prazosin
Alpha 1 Antagonist
Treatment for hypertension and benign prostatic
hyperplasia
Side effects: Postural orthostatic/ hypotension related to 1st dose phenomena
Tamsulosin
Alpha 1 Antagonist
Treatment for benign prostatic hyperplasia More
selective for genitourinary smooth muscle receptor subtype (a1A)
Side effects: Less postural / orthostatic hypotension
Clonidine
Alpha 2 Agonist
Treatment for hypertension and opioid withdrawal
• Side Effects: Bradycardia & hypotension
Oxymetaxoline
Alpha 1 and Alpha 2 agonist
•Topical/Nasal decongestant (Vicks, Sudafed, Afrin, Dristan); treats ocular hyperemia - eye redness (Visine
Phenoxybenzamine
Alpha 1 and Alpha 2 Antagonist
- Non-selective, non-competitive
- Irreversable
• Manages hypertension caused by pheochromocytoma
Phentolamine
Alpha 1 and Alpha 2 Antagonist
- Reversible, competitive antagonist
- Manages hypertension caused by pheochromocytoma
Dobutamine
Beta 1 Agonist
increased contractility and cardiac output but not heart rate – nio change in peripheral resistance
Short half life due to COMT metabolism
Used in ACUTE management of heart failure
Albuterol
Beta 2 Agonist
Used as “asthma reliever‟. Rapid action (15 min) relative short duration (4-6 hours)
Pindolol
Partial Beta Agonist
Clinically used for treatment of hypertension in
patients with bradycardia or low cardiac reserve
Atenolol
Beta 1 Antagonist
Treats hypertension and angina, reduces blood
volume via ↓ renin production
Side Effects: Sedation and dyspnea
Propranolol
Nonselective Beta Antagonist
Treatment for hypertension & angina
Side effects: More severe sedation, bronchoconstriction and dyspnea
Amphetamines
Inhibitor of CA storage
Displaces endogenous CA from storage vesicles
Blocks Norepinephrine Transporter (NET)
Weak inhibitor of MAO
Ephedrine & Pseudoephedrine
Inhibitor of CA storage
Used for nasal decongestion – increase NE activity at post synaptic Alpha- and Beta-receptors
Cocaine
Inhibotor of NE uptake via transporter (NET)
Imipramine
Re-uptake inhibitor (NET)
Used for treating mild depression
Side effects: Postural hypotension & tachycardia