SURITAL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for SURITAL (SURITAL).
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.
| Metabolism | Primarily hepatic metabolism via microsomal enzyme oxidation (CYP2B6, CYP3A4) to inactive metabolites; minor renal excretion. |
| Excretion | Primarily renal excretion of metabolites; <1% unchanged. Minor biliary/fecal elimination. |
| Half-life | Terminal elimination half-life 2-8 hours (mean 4.5 h) in adults; prolonged in hepatic impairment. |
| Protein binding | ~70% bound to albumin. |
| Volume of Distribution | 1.5-2.5 L/kg; indicates extensive tissue distribution. |
| Bioavailability | IM: ~90%. |
| Onset of Action | IV: 30-60 seconds; IM: 2-5 minutes. |
| Duration of Action | IV: 5-15 minutes (single dose); IM: 10-30 minutes. Longer with continuous infusion. |
| Molecular Weight | 376.43 |
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.
| Dosage form | INJECTABLE |
| Renal impairment | No specific GFR-based adjustments; metabolized primarily in liver. Caution in severe renal impairment due to potential accumulation of inactive metabolites. |
| Liver impairment | 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). |
| Pediatric use | Induction: 3-6 mg/kg IV. Maintenance: 1-2 mg/kg IV as needed. Use with caution; not recommended for neonates. |
| Geriatric use | Reduce dose by 30-50% due to decreased clearance and increased sensitivity. Administer slowly and titrate to effect. |
| 1st trimester | Avoid use; teratogenic effects reported in animal studies. No adequate human data. |
| 2nd trimester | Use only if clearly needed; may cause maternal hypotension and fetal hypoxia. |
| 3rd trimester | Avoid near term; may cause neonatal respiratory depression and hypotonia. |
Clinical note
Comprehensive clinical and safety monograph for SURITAL (SURITAL).
| Placental transfer | Rapidly crosses the placenta within seconds to minutes. |
| Breastfeeding | Excreted in breast milk in low concentrations. Use with caution; monitor infant for sedation. |
| Lactation Rating | L3 (Moderately Safe) |
■ FDA Black Box Warning
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.
| Serious Effects |
Hypersensitivity to barbituratesAcute intermittent porphyriaSevere respiratory depressionStatus asthmaticus
| Precautions | 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. |
| Food/Dietary | 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. |
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| Teratogenic Risk | 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. |
| Fetal Monitoring | Monitor maternal vital signs, ECG, respiratory rate, and oxygen saturation continuously during administration. Fetal heart rate monitoring (non-stress test or biophysical profile) if used near delivery. Assess for signs of uterine hyperstimulation if used for obstetrical procedures. Evaluate neonatal for respiratory depression, low Apgar scores, and withdrawal symptoms post-delivery. |
| Fertility Effects | No specific human data on fertility impairment. Animal studies indicate no adverse effects on fertility at therapeutic doses. However, chronic use may disrupt menstrual cycle and hormonal balance via hypothalamic-pituitary-adrenal axis suppression. Not recommended for long-term use in women of childbearing age due to unknown risks. |
| Clinical Pearls | 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. |
| Patient Advice | 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. |