Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
SURITAL vs PENTOTHAL
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
SURITAL (thiamylal) is an ultra-short-acting barbiturate that enhances GABA-A receptor activity, increasing chloride ion conductance and neuronal hyperpolarization, resulting in rapid induction of anesthesia.
Potentiates GABA-A receptor activity, enhancing inhibitory neurotransmission; also reduces excitatory glutamate signaling.
Induction of anesthesia,Maintenance of anesthesia as part of balanced anesthesia,Adjunct to regional anesthesia,Control of convulsive states (off-label)
Induction of general anesthesia,Induction of coma for increased intracranial pressure,Status epilepticus (off-label)
Induction: 3-5 mg/kg IV bolus over 10-15 seconds. Maintenance: 0.5-1.5 mg/kg IV as needed for anesthesia. Also used as 0.2-0.4% solution for IV infusion at 0.5-2 mg/min.
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 2-8 hours (mean 4.5 h) in adults; prolonged in hepatic impairment.
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.
Primarily hepatic metabolism via microsomal enzyme oxidation (CYP2B6, CYP3A4) to inactive metabolites; minor renal excretion.
Hepatic; primarily via CYP2C9 and other CYP450 enzymes.
Primarily renal excretion of metabolites; <1% unchanged. 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.
~70% bound to albumin.
Approximately 72-86% bound, primarily to albumin (with some binding to lipoproteins).
1.5-2.5 L/kg; indicates extensive tissue distribution.
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.
IM: ~90%.
IV: 100%. Rectal: approximately 60-80% (with variability). IM: approximately 60-70%. Oral: negligible due to extensive first-pass metabolism (not used clinically).
No specific GFR-based adjustments; metabolized primarily in liver. Caution in severe renal impairment due to potential accumulation of inactive metabolites.
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% and titrate to effect. Child-Pugh C: Contraindicated or use with extreme caution with reduced doses (e.g., 25-50% of normal).
Reduce dose by 50% in Child-Pugh B and C; monitor for prolonged sedation.
Induction: 3-6 mg/kg IV. Maintenance: 1-2 mg/kg IV as needed. Use with caution; not recommended for neonates.
Induction: 5-6 mg/kg IV; Maintenance: 1-2 mg/kg IV as needed; Rectal: 25 mg/kg (max 1.5 g).
Reduce dose by 30-50% due to decreased clearance and increased sensitivity. Administer slowly and titrate to effect.
Reduce induction dose to 2-3 mg/kg IV; use lower maintenance doses; increased risk of hypotension and respiratory depression.
WARNING: RESPIRATORY DEPRESSION AND CARDIAC ARREST. SURITAL may cause severe respiratory depression or apnea, especially with rapid administration. Resuscitative equipment and personnel trained in airway management must be immediately available. Avoid intra-arterial injection due to risk of arteriospasm, thrombosis, and gangrene.
WARNING: RESPIRATORY DEPRESSION AND APNEA; RESUSCITATIVE EQUIPMENT AND PERSONNEL MUST BE IMMEDIATELY AVAILABLE. INTRA-ARTERIAL INJECTION MAY CAUSE ARTERIAL SPASM, THROMBOSIS, AND GANGRENE.
Monitor respiratory and cardiac function continuously; use with caution in patients with respiratory compromise, hypotension, shock, or hepatic/renal impairment; may cause laryngospasm, bronchospasm, or hypotension; avoid extravasation; use with caution in porphyria.
Respiratory depression, hypotension, laryngospasm, bronchospasm, cardiac arrhythmias, extravasation risk, and acute porphyria exacerbation.
Absolute: Known hypersensitivity to barbiturates, acute intermittent porphyria, severe respiratory insufficiency, status asthmaticus, and conditions where general anesthesia is contraindicated.
Hypersensitivity to barbiturates, acute porphyria, severe respiratory or cardiovascular instability, and inadequate airway management capability.
No specific food interactions reported for Surital (thiamylal). However, patients should avoid consuming grapefruit or grapefruit juice for 24 hours before and after administration, as it may theoretically inhibit cytochrome P450 metabolism, although significant interactions are not well-documented.
No specific food interactions. However, avoid alcohol for at least 24 hours due to additive CNS depression.
Pregnancy Category D (positive evidence of human fetal risk). First trimester: Risk of congenital anomalies (limb defects, CNS malformations) based on animal studies and limited human data. Second/third trimester: Increased risk of preterm labor, fetal bradycardia, neonatal respiratory depression, and withdrawal syndrome. Avoid use during pregnancy unless clearly needed.
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 breast milk is unknown; M/P ratio not established. Due to high lipid solubility, potential for significant transfer. Consider risks of neonatal CNS depression. Use with caution; monitor infant for sedation, poor feeding, and respiratory depression. Alternative agents preferred.
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.
Increased volume of distribution and hepatic metabolism in pregnancy may require higher induction doses and more frequent maintenance doses. However, due to fetal risks, avoid use in pregnancy unless absolutely necessary. If used, start at lower range (e.g., 3-4 mg/kg IV induction) and titrate to effect. No established dose adjustment guidelines; individualize based on clinical response and close 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.
Surital (thiamylal) is an ultra-short-acting barbiturate used for induction of anesthesia. Due to its high lipid solubility, onset of action is rapid (<30 seconds). It is contraindicated in porphyria and should be used with caution in patients with hepatic impairment, as it is metabolized in the liver. Extravasation causes tissue necrosis; use a large vein for IV administration. Respiratory depression and laryngospasm are common during induction. Surital has no analgesic properties and may cause myocardial depression at high doses. For short procedures, it provides rapid awakening but with potential residual sedation.
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.
This medication is used to put you to sleep before surgery or certain procedures.,You may feel dizzy or drowsy for several hours after receiving this drug; do not drive or operate machinery for at least 24 hours.,Avoid alcohol for at least 24 hours after receiving this medication as it can increase side effects.,Inform your healthcare provider if you have a history of porphyria, liver disease, or respiratory problems.,Do not breastfeed for at least 24 hours after administration without consulting your doctor.,Notify your doctor immediately if you experience severe pain, redness, or swelling at the injection site.,You may experience temporary confusion or memory loss after waking up; this is normal and should resolve.
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 SURITAL vs PENTOTHAL, answered by our medical review team.
SURITAL is a Barbiturate Anesthetic that works by SURITAL (thiamylal) is an ultra-short-acting barbiturate that enhances GABA-A receptor activity, increasing chloride ion conductance and neuronal hyperpolarization, resulting in rapid induction of 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 SURITAL 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 SURITAL is: Induction: 3-5 mg/kg IV bolus over 10-15 seconds. Maintenance: 0.5-1.5 mg/kg IV as needed for anesthesia. Also used as 0.2-0.4% solution for IV infusion at 0.5-2 mg/min.. 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 SURITAL 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. SURITAL is classified as Category C. Pregnancy Category D (positive evidence of human fetal risk). First trimester: Risk of congenital anomalies (limb defects, CNS malformations) based on animal studies and limited hu. 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.