Direct Cholinergic Agonists

Question 1

Miochol-E (Acetylcholine Chloride)

Answer 1

Pharmacology: Direct ACh Agonist, Non-selective for receptors. Given intraocular.
Indications: Miosis of the eye during cataract surgery, penetrating keratoplasty, iridectomy.
Adverse Rxns: Local:corneal edema, corneal decompensation, corneal clouding.
Systemic: bradycardia, hypotension, flushing, sweating, difficulty breathing.

Question 2

Methacholine (provocholine)

Answer 2

Pharmacology: Given by inhalation. Beta-methyl analog of ACh. Slowly hydrolyzed by AChE. Selective for muscarinic receptors. Racemate mixture: S(+) more active, R(-)more stable because it inhibits AChE.
Indications: Diagnosis of bronchial airway hyper-reactivity.
Contraindications: should not be given to patients taking any Beta-adrenergic blocking agents.

Question 3

Bethanecol (Urecholine)

Answer 3

Pharmacology: Orally more potent. Carbamate ester of methacholine. S enantiomer has greater affinity for muscarinic receptor then R enantiomer. M3 receptor on smooth muscle of bladder and GI tract. Initiates urination and stimulates/restores peristalsis.
Indications: Urinary retention from acute postoperative and postpartum as well as neurogenic atony (spina bifida)

Question 4

Cabachol (Miostat)

Answer 4

Pharmacology: Cabamate ester of ACh. Potent cholinergic agonist. Hydrolyzed more slowly than ACh. Produces constiction of the iris and cilliary body resulting in reduction in intraocular pressure.
Indications: Treat glaucoma. Intraocular use to induce miosis during surgery. Reduces intensity of IOP elevation in the first 24 hrs after cataract surgery.
Adverse reactions: Ocular: Corneal clouding, keratopathy, retinal detachment, post operative iritis. Systemic: flusching, sweating, epigastric distress, abdominal cramps, tightness in urinary bladder, and headache.

Question 5

Isopto Carpine (Prolicarpine)

Answer 5

Pharmacology: Alkaloid. Muscarinic cholinergic agonist.
Indications: Eye: reduction of elevated intraocular pressure (IOP) in patients with open-angle glaucoma or ocular hypertension. Prevent IOP after laser surgery. Induce miosis.
Adverse Reaction: headache/brow ache, accommodative change, eye irritation, eye pain, blurred vision, and/visual imparement.

Question 6

Salagen (Pilocarpine)

Answer 6

Pharmacology: Alkaloid. Muscarinic cholinergic agonist.
Indication: Increase salivation from dry mouth due to salivary gland hypofunction caused by chemotherapy for cancer of the head and neck. Dry mouth in pations with Sjogren’s syndrome.
Adverse reactions: headache/brow ache, accomodative change, eye irritation, eye pain, blurred vision, and/or visual impairment.

Question 7

Ocusert (Pilocarpine)

Answer 7

Pharmacology: Alkaloid. Muscarinic cholinergic agonist.
Adverse effects: headache/brow ache, acommodative change, eye irritation, eye pain, blurred vision, and/or visual impairment.

Question 8

Cevimeline (Evoxac)

Answer 8

Pharmacology: Muscarinic agonist with high affinity for M3 muscarinic receptors on lacrimal and salivary gland epithelia. Long lasting salivary action, and has fewer side effects than pilocarpine.