[.
]
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.
t
1/2: 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.
