Myotonachol


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Myotonachol

 [mi″o-tōn-ah-kol]
trademark for preparations of bethanechol chloride, a smooth muscle relaxant used to treat urinary retention.

bethanechol chloride

Duvoid (CA), Myotonachol (CA), Myotonine (UK), PMS-Bethanecol Chloride (CA), Urecholine

Pharmacologic class: Cholinergic

Therapeutic class: Urinary and GI tract stimulant

Pregnancy risk category C

Action

Stimulates parasympathetic nervous system and cholinergic receptors, leading to increased muscle tone in bladder and increased frequency of ureteral peristaltic waves. Also stimulates gastric motility, increases gastric tone, and restores rhythmic GI peristalsis.

Availability

Tablets: 5 mg, 10 mg, 25 mg, 50 mg

Indications and dosages

Postpartal and postoperative non-obstructive urinary retention; urinary retention caused by neurogenic bladder

Adults: 10 to 50 mg P.O. three to four times daily; dosage may be determined by giving 5 or 10 mg q hour until response occurs or a total of 50 mg has been given.

Contraindications

• Hypersensitivity to drug

• GI or GU tract obstruction

• Hyperthyroidism

• Active or latent asthma

• Bradycardia

• Hypotension

• Atrioventricular conduction defects

• Coronary artery disease

• Seizure disorders

• Parkinsonism

• Peptic ulcer disease

Precautions

Use cautiously in:

• sensitivity to cholinergics or their effects and tartrazine (some products)

• pregnant or breastfeeding patients

• children.

Administration

• Give drug on empty stomach 1 hour before or 2 hours after a meal to help prevent nausea and vomiting.

Adverse reactions

CNS: headache, malaise, seizures

CV: bradycardia, hypotension, heart block, syncope with cardiac arrest

EENT: excessive lacrimation, miosis

GI: nausea, vomiting, diarrhea, abdominal discomfort, belching

GU: urinary urgency

Respiratory: increased bronchial secretions, bronchospasm

Skin: diaphoresis, flushing

Other: hypothermia

Interactions

Drug-drug. Anticholinergics: decreased bethanechol efficacy

Cholinesterase inhibitors: additive cholinergic effects

Depolarizing neuromuscular blockers: decreased blood pressure

Ganglionic blockers: severe hypotension

Procainamide, quinidine: antagonism of cholinergic effects

Drug-herbs. Angel's trumpet, jimson-weed, scopolia: antagonism of cholinergic effects

Patient monitoring

• Monitor blood pressure. Be aware that hypertensive patients may experience sudden blood pressure drop.

• Stay alert for orthostatic hypotension, a common adverse effect.

• Monitor fluid intake and output and residual urine volume.

Patient teaching

• Tell patient that drug is usually effective within 90 minutes of administration.

• Advise patient to take drug on empty stomach 1 hour before or 2 hours after a meal to avoid GI upset.

• Instruct patient to move slowly when sitting up or standing, to avoid dizziness or light-headedness from blood pressure decrease.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and herbs mentioned above.

Myotonachol

a trademark for a cholinergic (bethanechol chloride).