Search
tubocurarine (Tubarine)
An alkaloid present in curare derived from Chondodendron species. Tradename: Tubarine.
Indications:
1) skeletal muscle relaxation during surgery & electroshock therapy
2) has been used as a diagnostic agent for myasthenia gravis
3) must ALWAYS be used with sedative (i.e. lorazepam) anesthetics & analgesics as needed
Dosage:
1) adjunct to anesthesia: 6-9 mg IV/IM followed by 3-4 mg every 3-5 min PRN
2) electroshock therapy: 0.165 mg/kg (administer 3 mg less than the calculated dose)
3) myasthenia gravis: 0.004-0.033 mg/kg
Injection: 3 mg/mL (10 mL).
Pharmacokinetics:
1) rapid onset of action
a) 2-5 minutes after IV administration
b) 10-20 minutes after IM administration
2) duration of action: 20-40 minutes after IV administration
3) 30-80% is eliminated unchanged in the urine
4) metabolized in the liver
Adverse effects:
1) not common (1-10%)
- hypotension
2) uncommon (< 1%)
- rash, itching, flushing, erythema, edema, circulatory collapse, cardiac arrhythmias, bronchospasm, tachycardia, bradycardia, increased salivation, decreased GI motility, hypersensitivity, allergic reactions
3) other
- muscle weakness
- redness at the site of injection
- increased adverse effects with hyperkalemia or hypokalemia Toxicity (reversal of effects):
- neostigmine, pyridostigmine, edrophonium (cholinesterase inhibitor) used with atropine (muscarinic inhibition) to reverse muscular blockade
Drug interactions:
1) aminoglycosides, tetracyclines, clindamycin, corticosteroids: in combination cause prolonged muscle weakness
2) K+ depleting agents (thiazides, loop diuretics, amphotericin B, corticosteroids) can increase & prolong muscle paralysis
3) neostigmine, pyridostigmine, edrophonium, & other cholinesterase inhibitors are used with atropine to reverse muscular blockade
4) quinidine
5) magnesium sulfate
6) verapamil
7) ketamine
Laboratory:
1) specimen: serum, plasma (EDTA)
2) methods: HPLC, color, fluorometry, RIA
Mechanism of action:
1) non-depolarizing neuromuscular junction blocker
2) skeletal muscle relaxation produced by blocking response to acetylcholine at the myoneural junction
3) blocks access of acetylcholine to the motor end-plate
4) also inhibits ganglionic transmission & induces release of histamine
Interactions
drug interactions
General
alkaloid
neuromuscular blocker (paralyzing agent)
phenol
Properties
MISC-INFO: elimination route KIDNEY
1/2life 2-3 HOURS
therapeutic-range >0.7 UG/ML <99% paralysis>
toxic-range >500 NG/ML
protein-binding 48-54%
Database Correlations
PUBCHEM correlations
References
- Clinical Guide to Laboratory Tests, 3rd edition, NW Tietz
ed, WB Saunders, Philadelphia, 1995
- Drug Information & Medication Formulary, Veterans Affairs,
Central California Health Care System, 1st ed., Ravnan et al
eds, 1998 - not on National VA formulary
- Kaiser Permanente Northern California Regional Drug
Formulary, 1998
- Clinical Guide to Laboratory Tests, NW Tietz (ed) 3rd ed,
WB Saunders, Philadelpha 1995
- Stedman's Medical Dictionary 27th ed, Williams &
Wilkins, Baltimore, 1999
- The Pharmacological Basis of Therapeutics, 9th ed.
Gilman et al, eds. Permagon Press/McGraw Hill, 1996 pg 178