1. NICOTINIC ANTAGONIST
1.1. Neuromuscular Blockers
1.1.1. tubocurarine
1.2. Ganglion Blockers
1.2.1. Hexamethonium
2. MUSCARINIC ANTAGONIST
2.1. What is it?
2.1.1. agent that has high binding affinity for muscarinic receptor, but no intrinsic activity
2.1.2. reversible competitive antagonist
2.1.3. aka anticholinergics, antimuscarinics, cholinergic blockers, antispasmodics, parasympatholytics
2.1.4. M1
2.1.4.1. located on CNS neurons
2.1.4.2. sympathetic postganglionic cell bodies & many presynaptic sites
2.1.5. M2
2.1.5.1. located in the myocardium
2.1.5.2. smooth muscle organs
2.1.5.3. some neuronal sites
2.1.6. M3
2.1.6.1. Effector cell membranes especially glandular & smooth muscle cells
2.1.7. M4 & M5
2.1.7.1. less prominent & play greater role in CNS & PNS
2.2. Drugs
2.2.1. Natural , tertiary amine
2.2.1.1. Atropine
2.2.1.1.1. Pharmacokinetics
2.2.1.1.2. Pharmacodynamics
2.2.1.1.3. Clinical uses
2.2.1.1.4. side effects
2.2.1.2. Scopolamine (Hyoscine)
2.2.1.2.1. Pharmacokinetics
2.2.1.2.2. Pharmacodynamics
2.2.1.2.3. Clinical use
2.2.2. Synthetic quarternary amine
2.2.2.1. Ipratropium bromide (short acting)
2.2.2.1.1. Blocks cholinergic bronchiole constriction - allows bronchiole dilation to overcome pulmonary constriction
2.2.2.1.2. Uses / CI
2.2.2.1.3. Adverse effects
2.2.2.2. Tiotropium bromide (long acting)
2.2.2.2.1. Same MOA and CI as ipratropium bromide
2.2.2.2.2. Adverse effects
2.2.2.3. Bronchoconstriction
2.2.2.3.1. Ipratropium & Tiotropium MOA
2.2.3. Cyclopentolate
2.2.3.1. Clinical use
2.2.3.1.1. to produce mydriasis & cyclopegia for diagnostic purposes
2.2.3.2. MOA
2.2.3.2.1. Antimuscarinic that blocks receptor in the muscle of the eye → involve in controlling the pupil size & shape of the lens
2.2.3.2.2. Induce relaxation of the sphincter of the iris and the ciliary muscle
2.2.3.2.3. Relationship between iris sphincter and ciliary muscle is shown in normal eye (Diagram A)
2.2.3.2.4. Diagram C – atropine is administered → iris sphincter and ciliary muscle relax
2.2.3.2.5. Produce pupillary dilatation (mydriasis) → increase tension of suspensory ligaments → lens thinner → focus distant object
2.2.3.2.6. Topically → rapid intense cycloplegic and mydriatic effect (15-60min)
2.2.4. Pirenzepine
2.2.4.1. M1 selective antagonist
2.2.4.2. Clinical use
2.2.4.2.1. peptic ulcer disease
2.2.4.3. MOA
2.2.4.3.1. Inhibit gastric acid secretion in the stomach
2.2.4.4. Adverse reaction
2.2.4.4.1. Dry mouth
2.2.4.4.2. difficulty of accommodation is less common in pirenzipine compared to atropine