[.
]Action/Kinetics:
Cumulative effects may occur. Most likely of the nondepolarizing drugs to cause histamine release. Narrow margin between therapeutic dose and toxic dose. Onset, IV: 1 min; IM: 15-25 min. Time to peak effect, IV: 2-5 min. Duration, IV: 20-90 min. t1/2: 1-3 hr. About 43% excreted unchanged in urine.
Uses:
Muscle relaxant during surgery or setting of fractures and dislocations; spasticity caused by injury to or disease of CNS. Treat seizures electrically induced or induced by drugs. Diagnosis of myasthenia gravis.
Additional Contraindications:
Clients in whom release of histamine is hazardous.
Special Concerns:
Use with caution during pregnancy and lactation and in children. If repeated doses are used before delivery, the newborn may manifest decreased skeletal muscle activity. Children up to 1 month of age may be more sensitive to the effects of tubocurarine. Use with extreme caution in clients with renal dysfunction, liver disease, or obstructive states.
Additional Side Effects:
Allergic reactions. Excessive secretion and circulatory collapse.
Overdose Management:
Treatment: Overdosage chiefly treated by artificial respiration, although neostigmine, atropine, and edrophonium chloride should also be on hand.
Additional Drug Interactions:
- Acetylcholine / Antagonizes effect of tubocurarine
- Anticholinesterases / Antagonizes effect of tubocurarine
- Calcium salts /
Tubocurarine effect
- Diazepam / Risk of malignant hyperthermia
- Potassium / Antagonizes effect of tubocurarine
- Propranolol / Tubocurarine effect
- Quinine / Tubocurarine effect
- Succinylcholine chloride / Relaxant effect of both drugs
How Supplied:
Injection: 3 mg/mL
Dosage
•IV, IM
Adjunct to surgical anesthesia.
Adults, IM, IV, initial: 6-9 mg (40-60 units); then, 3-4.5 mg (20-30 units) in 3-5 min if needed. Supplemental doses of 3 mg (20 units) can be given for prolonged procedures. Dosage can be calculated on the basis of 1.1 units/kg. Pediatric, up to 4 weeks of age, IV, initial: 0.3 mg/kg; then, give subsequent doses in increments of 1/5-1/6 the initial dose. Infants and children, IV: 0.6 mg/kg.
Electroshock therapy.
Adults, IV: 0.165 mg/kg (1.1 units/kg) given over 30-90 sec. It is recommended that the initial dose be 3 mg less than the calculated total dose.
Diagnosis of myasthenia gravis.
Adults, IV: 0.004-0.033 mg/kg. A test dose should be given within 2-3 min with IV neostigmine, 1.5 mg, to minimize prolonged respiratory paralysis.
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