Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
BREVITAL SODIUM vs PENTOTHAL
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Brevital sodium (methohexital) is a barbiturate that acts as a GABA-A receptor agonist, enhancing chloride ion influx and hyperpolarizing neurons, leading to rapid sedation and anesthesia.
Potentiates GABA-A receptor activity, enhancing inhibitory neurotransmission; also reduces excitatory glutamate signaling.
Induction and maintenance of general anesthesia,Adjunct to regional anesthesia,Short-duration surgical procedures
Induction of general anesthesia,Induction of coma for increased intracranial pressure,Status epilepticus (off-label)
Induction of anesthesia: 1-1.5 mg/kg IV bolus over 15 seconds; maintenance: 0.5-1 mg/kg IV bolus as needed or 50-150 mcg/kg/min IV infusion.
Induction: 3-5 mg/kg IV; Maintenance: 25-75 mg IV as needed; Rectal: 25 mg/kg (max 1.5 g) for induction.
Terminal elimination half-life: 3–6 hours (mean ~4 hours); prolonged in hepatic impairment, obesity, or with repeated dosing due to redistribution.
Terminal elimination half-life is 5-12 hours (mean 8 hours) in adults. Prolonged with hepatic impairment, obesity, or high doses due to saturation of redistribution and metabolism.
Hepatic metabolism primarily by CYP2C9 and CYP3A4 to inactive metabolites; less than 1% excreted unchanged in urine.
Hepatic; primarily via CYP2C9 and other CYP450 enzymes.
Primarily hepatic biotransformation to inactive metabolites (mainly hydroxy-methohexital), with renal excretion of metabolites; less than 1% excreted unchanged in urine. Minor biliary/fecal elimination.
Hepatic metabolism (approx. 80%), renal excretion of metabolites (20-30%) and unchanged drug (0.3-1%). Biliary/fecal elimination is negligible.
Approximately 70–90% bound to albumin.
Approximately 72-86% bound, primarily to albumin (with some binding to lipoproteins).
Vd: 1.1–2.5 L/kg (mean ~1.5 L/kg). Larger Vd indicates extensive tissue distribution (highly lipophilic), leading to rapid redistribution and short duration after single bolus.
Vd = 1.0-2.5 L/kg (mean 1.5 L/kg). High Vd due to extensive tissue distribution, including brain and fat; correlates with high lipid solubility.
IV: 100%. IM: Not well established; likely >90%. Rectal: Variable, ~50–70% due to first-pass metabolism and incomplete absorption.
IV: 100%. Rectal: approximately 60-80% (with variability). IM: approximately 60-70%. Oral: negligible due to extensive first-pass metabolism (not used clinically).
No dosage adjustment required for GFR ≥10 m L/min; for GFR <10 m L/min, reduce dose by 50%.
No specific GFR-based adjustment; use with caution in severe renal impairment due to prolonged effects.
Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: reduce dose by 75% or consider alternative.
Reduce dose by 50% in Child-Pugh B and C; monitor for prolonged sedation.
Induction: 1-2 mg/kg IV; maintenance: 0.5-1 mg/kg IV bolus or 50-150 mcg/kg/min IV infusion. Contraindicated in infants <2 months with stable BSA.
Induction: 5-6 mg/kg IV; Maintenance: 1-2 mg/kg IV as needed; Rectal: 25 mg/kg (max 1.5 g).
Reduce induction dose by 50% and administer slowly over 60 seconds; maintenance infusion rates at lower end (50-100 mcg/kg/min).
Reduce induction dose to 2-3 mg/kg IV; use lower maintenance doses; increased risk of hypotension and respiratory depression.
None.
WARNING: RESPIRATORY DEPRESSION AND APNEA; RESUSCITATIVE EQUIPMENT AND PERSONNEL MUST BE IMMEDIATELY AVAILABLE. INTRA-ARTERIAL INJECTION MAY CAUSE ARTERIAL SPASM, THROMBOSIS, AND GANGRENE.
Respiratory depression and apnea may occur; resuscitative equipment must be available,Hypotension and bradycardia possible; use with caution in patients with cardiovascular disease,Extravasation causes tissue necrosis; avoid intra-arterial injection,Seizures may occur in epileptic patients,Rapid injection may cause severe respiratory depression
Respiratory depression, hypotension, laryngospasm, bronchospasm, cardiac arrhythmias, extravasation risk, and acute porphyria exacerbation.
Known hypersensitivity to barbiturates,Porphyria (may precipitate acute attacks),Severe respiratory insufficiency,Status asthmaticus,Hypovolemic shock or severe hypotension
Hypersensitivity to barbiturates, acute porphyria, severe respiratory or cardiovascular instability, and inadequate airway management capability.
No specific food interactions are documented for BREVITAL SODIUM. However, patients should avoid heavy meals before anesthesia due to risk of aspiration. Do not consume alcohol or grapefruit juice for 24 hours before and after administration, as they may alter drug metabolism and increase sedation.
No specific food interactions. However, avoid alcohol for at least 24 hours due to additive CNS depression.
Teratogenic potential not fully established in humans. In animal studies, methohexital caused fetal resorptions and malformations at maternally toxic doses. First trimester: Avoid unless essential; risk of neural tube defects cannot be excluded. Second trimester: Limited data, but may cause fetal depression if used near delivery. Third trimester: Crosses placenta; may cause neonatal respiratory depression, hypotonia, and prolonged sedation. Use only if clearly needed with lowest effective dose.
PENTOTHAL (thiopental) crosses the placenta. First trimester: limited human data, animal studies show no consistent teratogenicity. Second trimester: no specific malformation risk. Third trimester: prolonged maternal administration may cause neonatal respiratory depression, hypotonia, and withdrawal. Use only if clearly needed.
Excretion into human milk unknown. M/P ratio not determined. Due to short half-life, minimal transfer expected after a single dose. Caution with repeated doses or prolonged infusion. Monitor infant for sedation, feeding difficulties, or respiratory depression.
Thiopental is excreted in breast milk. M/P ratio is approximately 0.4–0.8. Infant dose is low (<1% of maternal weight-adjusted dose), but caution is advised due to potential CNS depression. American Academy of Pediatrics considers compatible with breastfeeding, but monitor infant for sedation.
Pregnancy may increase volume of distribution and clearance, potentially requiring higher initial doses, but the induction dose typically unchanged. Reduced doses may be needed in preeclampsia or cesarean section due to enhanced sensitivity. No specific dose adjustment guidelines; titrate to effect with careful monitoring.
Pregnancy may increase volume of distribution and clearance, but dosing adjustments for thiopental are not routinely recommended. Use lowest effective dose due to increased sensitivity to barbiturates. For cesarean section, standard induction doses (3-5 mg/kg IV) are used; reduced doses may be needed if combined with other sedatives.
BREVITAL SODIUM (methohexital) is an ultrashort-acting barbiturate used for induction of anesthesia and for short procedures. Due to its rapid onset and brief duration, it requires careful titration. It is contraindicated in patients with porphyria. Extravasation causes tissue necrosis; administer only through a secure IV line. It lowers seizure threshold, but can also be used for electroconvulsive therapy (ECT) to induce seizures. Respiratory depression and hypotension are dose-dependent; have resuscitation equipment ready. Avoid in patients with severe hepatic impairment. Coadministration with opioids or benzodiazepines potentiates sedation and respiratory depression.
Pentothal (thiopental) is an ultra-short-acting barbiturate used for induction of anesthesia. It causes dose-dependent respiratory depression and hypotension. Administer only in a controlled setting with resuscitation equipment. Note that it is highly alkaline (p H 10-11) and extravasation causes severe tissue necrosis. Also, it is contraindicated in porphyria.
BREVITAL SODIUM is a potent anesthetic that causes rapid loss of consciousness and should only be administered by trained medical professionals.,You may experience temporary pain or burning at the injection site; report any persistent pain or swelling to your healthcare provider.,Drowsiness, dizziness, and confusion may persist for several hours after the procedure; do not drive or operate machinery for at least 24 hours.,Avoid alcohol and other sedatives for 24 hours before and after the procedure as they may increase side effects.,Inform your doctor if you have a history of porphyria, liver disease, or drug allergies.,If you are pregnant or breastfeeding, discuss the risks and benefits with your healthcare provider.
You will receive this medication only under the supervision of an anesthesiologist.,It will cause you to fall asleep quickly and you may feel drowsy for several hours after the procedure.,Do not drive or operate machinery for at least 24 hours after receiving this medication.,Inform your doctor if you have a history of porphyria, liver disease, or allergies to barbiturates.,You may experience a bad taste or cough upon injection.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about BREVITAL SODIUM vs PENTOTHAL, answered by our medical review team.
BREVITAL SODIUM is a Barbiturate Anesthetic that works by Brevital sodium (methohexital) is a barbiturate that acts as a GABA-A receptor agonist, enhancing chloride ion influx and hyperpolarizing neurons, leading to rapid sedation and anesthesia.. PENTOTHAL is a Barbiturate Anesthetic that works by Potentiates GABA-A receptor activity, enhancing inhibitory neurotransmission; also reduces excitatory glutamate signaling.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between BREVITAL SODIUM and PENTOTHAL depend on the specific clinical indication. These are both Barbiturate Anesthetic agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of BREVITAL SODIUM is: Induction of anesthesia: 1-1.5 mg/kg IV bolus over 15 seconds; maintenance: 0.5-1 mg/kg IV bolus as needed or 50-150 mcg/kg/min IV infusion.. The standard adult dose of PENTOTHAL is: Induction: 3-5 mg/kg IV; Maintenance: 25-75 mg IV as needed; Rectal: 25 mg/kg (max 1.5 g) for induction.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between BREVITAL SODIUM and PENTOTHAL in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. BREVITAL SODIUM is classified as Category C. Teratogenic potential not fully established in humans. In animal studies, methohexital caused fetal resorptions and malformations at maternally toxic doses. First trimester: Avoid . PENTOTHAL is classified as Category C. PENTOTHAL (thiopental) crosses the placenta. First trimester: limited human data, animal studies show no consistent teratogenicity. Second trimester: no specific malformation risk.. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.