Action And Clinical Pharmacology: Gallamine is a competitive neuromuscular blocking agent. It acts by combining with the cholinergic receptor sites in muscle and competitively blocking the transmitter action of acetylcholine. Gallamine has a parasympatholytic effect on the cardiac vagus nerve which causes tachycardia and occasionally hypertension. Very high doses cause histamine release.
Following usual i.v. doses muscle relaxation occurs rapidly and reaches a maximum within 3 minutes. The duration of action averages about 15 to 20 minutes. Redistribution of the drug is primarily responsible for termination of action after a single dose. Gallamine is excreted unchanged in the urine. Gallamine will cross the placenta and may produce significant serum levels in the infant.
Indications And Clinical Uses: Adjunctive medication: in general anesthesia to provide more complete muscular relaxation during minor and major surgical, manipulative orthopedic, endoscopic and intubation procedures; in obstetrics for delivery when the cervix is fully dilated.
May also be used to prevent accidents during electroshock therapy, to decrease severity of muscular spasms in tetanus, spastic paraplegia and other convulsive states.
Contra-Indications: Respiratory depression or deficiency, severe renal impairment, myasthenia gravis, iodine sensitivity.
Precautions: Use with caution in patients with hypertension or cardiac insufficiency when tachycardia would be undesirable; it should preferably be avoided in obstetric surgery.
If used with cyclopropane anesthesia, gallamine may provoke ventricular arrhythmias.
May be added to or mixed with Pentothal but not vice versa. Do not use syringes previously used for Pentothal. Do not use yellow colored solutions of the drug.
Gallamine should be administered by, or under the supervision of, an experienced anesthesiologist. Facilities for intubation, artificial respiration, and oxygen therapy should be available, as well as edrophonium or neostigmine and atropine as antidotes.
Adverse Reactions: Moderate increase in blood pressure. Ventricular rhythm changes may occur, which may be prevented by the administration of an association of halothane-nitrous oxide-oxygen. Respiratory muscle paresis may cause respiratory depression.
Dosage And Administration: After induction of light (second plane) anesthesia, administer as follows:
Surgery: Adults: about 1 mg/kg (40 to 80 mg). If necessary, repeated doses of 0.5 to 1 mg/kg or less, at intervals of 50 to 60 minutes or longer, may be given.
Children: up to 2 mg/kg. Since in children, the duration of action is shorter than in adults, additional doses should be repeated more frequently.
Obstetrics: 20 to 40 mg i.v. when the cervix is fully dilated.
Electroconvulsive Therapy: Average adult dose: 40 to 60 mg.
Availability And Storage: Each mL of injectable solution contains: 20 mg of gallamine triethiodide. Nonmedicinal ingredients: potassium metabisulfite, sodium sulfite and water for injection. Ampuls of 2 and 5 mL, boxes of 10. Protect from light.
FLAXEDIL® Rh´ne-Poulenc Rorer Gallamine Triethiodide Muscle Relaxant