Classifications: general anesthetic; barbiturate; Therapeutic: general anesthetic; barbituate
Pregnancy Category: B
Controlled Substance: Schedule IV
500 mg, 2.5 g, 5 g powder for injection
Rapid, ultra-short-acting barbiturate anesthetic agent. More potent than thiopental but has less cumulative effect and shorter
duration of action, and recovery is more rapid.
Induces brief general anesthesia without analgesia by depression of the CNS.
Induction of anesthesia, as supplement for other anesthetics, and as general anesthetic for brief operative procedures.
Hypersensitivity to methohexital sodium; agranulocytosis; barbiturate hypersensitivity; hepatic encephalopathy; intraarterial
administration; shock, heart failure, PVD, severe hypo- and hypertension, respiratory depression, infants <1 mo; neonates.
Pregnancy (category B), labor; adrenal insufficiency, anemia, carbamazepine hypersensitivity; cardiac disease, COPD; uncontrolled
asthma, status asthmaticus, sleep apnea, respiratory insufficiency, CNS depression; depression, ethanol intoxication; exfoliative
dermatitis; hepatic disease; hydantoin hypersensitivity, older adult; neuromuscular disease; obesity; porphyria; pulmonary
disease, renal disease, uremia, renal impairment; seizure disorders, status epilepticus, seizures; shock.
Route & Dosage
|Induction of Anesthesia
Adult: IV 50120 mg at a rate of 5 mg q5min, then 2040 mg q47min prn
Child/Infant: IM 6.610 mg/kg of 5% solution IV 12 mg/kg PR 2035 mg/kg (max: 500 mg/dose)
- Give to recumbent patient. Fall in BP may occur in susceptible patients receiving drug in upright position.
- Note: Verify with physician correct IV or IM concentration for infants or children as well as rate of IV infusion for administration
PREPARE: Direct: Prepare a 1% solution (10 mg/mL) by diluting with sterile water for injection, D5W, or NS. Use only clear, colorless
solutions. Do not allow contact with rubber stoppers or parts of syringes treated with silicone because solution is incompatible
with acid solutions (see IMCOMPATIBILITIES).
ADMINISTER: Direct: Give 5 mg over 510 sec.
INCOMPATIBILITIES Solution/additive: Atropine, chlorpromazine, glycopyrrolate, hydralazine, kanamycin, lidocaine, mechlorethamine, methyldopa, prochlorperazine, promazine, promethazine, streptomycin. Y-site: Fenoldopam.
- Store drug in sterile water for injection at room temperature for at least 6 wk. Solutions prepared with isotonic NaCl injection
or 5% dextrose injection are stable for ONLY about 24 h.
Adverse Effects (≥1%) CV:
Hypotension, cardiac arrhythmias, cardiac arrest. Musculoskeletal:
Muscle spasm. CNS:
Postoperative psychomotor impairment that persists for 24 hours, anxiety, drowsiness, emergence delirium, restlessness,
and seizures. Respiratory:
Bronchospasm, cough, hiccups, respiratory depression
, apnea, dyspnea, respiratory arrest. Skin:
Phlebitis and nerve injury adjacent to the injection site, local irritation, edema, ulceration, necrosis.
and other cns depressants
enhance CNS depression
17% absorbed PR. Distribution:
Crosses CNS, placenta and excreted in breast milk. Metabolism:
Oxidized in liver. Elimination:
Primarily excreted in urine.
Assessment & Drug Effects
- Hiccups are common, particularly with rapid injection; they sometimes persist after anesthesia.
- Keep facilities for assisting respiration and administration of oxygen readily available in the event of respiratory distress.