Comprehensive Guide to Thiopental: Uses, Dosage, Side Effects, and More

1. What is Thiopental?

2. Overview of Thiopental

Generic Name

Thiopental

Brand Name

Pentothal, generics

Drug Group

Barbiturate (general anesthetic)

Commonly Used For

This medication is used to:

• Induce general anesthesia.
• Control status epilepticus.
• Manage elevated intracranial pressure.

Key Characteristics

• Form: Powder for injection (500 mg, 1 g/vial) reconstituted for IV use (detailed in Dosage section).
• Mechanism: Enhances GABA-A receptor activity, causing sedation and hypnosis.
• Approval: FDA-approved (1930s for Pentothal) and EMA-approved for anesthesia and emergencies.

3. Indications and Uses of Thiopental

Thiopental is indicated for a variety of critical care and surgical applications, leveraging its rapid action and CNS depressant effects:

• Induction of General Anesthesia: Used for rapid induction in elective surgeries (e.g., orthopedic, abdominal), providing unconsciousness within 30–60 seconds, per anesthesiology protocols, with extensive historical use since the 1930s.
• Status Epilepticus: Treats refractory status epilepticus when benzodiazepines fail, terminating seizures within minutes, supported by neurology and critical care guidelines.
• Elevated Intracranial Pressure (ICP): Manages increased ICP in traumatic brain injury or neurosurgery, reducing cerebral metabolic rate, with evidence from neurocritical care studies.
• Rapid Sequence Intubation (RSI): Employed in emergency RSI to secure airways in trauma or respiratory failure, ensuring rapid unconsciousness, per emergency medicine standards.
• Electroconvulsive Therapy (ECT): Used off-label to induce anesthesia during ECT for severe depression or schizophrenia, minimizing convulsion intensity, supported by psychiatric research.
• Neuroprotection in Hypoxia: Investigated off-label for cerebral protection during cardiac arrest or hypoxic-ischemic encephalopathy, reducing brain damage, with data from resuscitation science.
• Pediatric Anesthesia: Administered off-label in children for short procedures (e.g., dental surgery), with adjusted dosing, under pediatric anesthesiology supervision.
• Sedation in ICU: Explored off-label for sedation in mechanically ventilated ICU patients, managing agitation, with critical care evidence.
• Anticonvulsant in Tetanus: Used off-label to control muscle spasms in severe tetanus, complementing other agents, supported by infectious disease and neurology studies.
• Historical Use in Lethal Injection: Previously utilized in some regions for capital punishment, though now largely discontinued, reflecting its historical context in medical and legal debates.

Note: This drug requires careful monitoring due to its narrow therapeutic index; consult a healthcare provider for administration and supportive care.

4. Dosage of Thiopental

Important Note: The dosage of this barbiturate must be prescribed by a healthcare provider. Dosing varies by indication, patient weight, and clinical status, with adjustments based on real-time assessment.

Dosage for Adults

• Induction of General Anesthesia:
  • 3–5 mg/kg IV over 10–15 seconds, titrated to effect; additional 25–50 mg doses as needed.
• Status Epilepticus:
  • 75–125 mg IV every 2–3 minutes until seizures stop, up to 250–500 mg total, with EEG monitoring.
• Elevated Intracranial Pressure:
  • 1.5–3 mg/kg IV bolus, followed by 1–2 mg/kg/hour infusion, adjusted for ICP response.

Dosage for Children

• Induction of Anesthesia or Status Epilepticus:
  • 2–4 mg/kg IV over 10–15 seconds, titrated to effect; additional 1–2 mg/kg doses if needed, under pediatric anesthesiologist supervision.
  • Not recommended under 1 month unless critical.

Dosage for Pregnant Women

• Pregnancy Category C: Use only if benefits outweigh risks (e.g., emergency surgery). Consult an obstetrician, with fetal monitoring.

Dosage Adjustments

• Renal Impairment: No adjustment needed; monitor in severe cases (CrCl <30 mL/min).
• Hepatic Impairment: Reduce dose by 25–50% if liver function is compromised (e.g., cirrhosis); avoid in severe cases.
• Elderly: Start with 2–3 mg/kg; increase cautiously with monitoring.
• Concomitant Medications: Adjust if combined with other CNS depressants (e.g., opioids), increasing sedation risk.

Additional Considerations

• Administer this active ingredient via IV push or infusion by a healthcare provider, using a secure line.
• Prepare with sterile water or saline, avoiding extravasation.

5. How to Use Thiopental

• Administration:
  • Reconstitute powder with sterile water or saline, administer IV push over 10–15 seconds or infuse slowly; avoid intra-arterial injection.
  • Use in a controlled setting with resuscitation equipment and monitoring.
• Timing: Administer as a single dose or continuous infusion based on indication, with frequent reassessment.
• Monitoring: Watch for respiratory depression, hypotension, or signs of overdose (e.g., unresponsiveness).
• Additional Tips:
  • Store at 20–25°C (68–77°F) before reconstitution; protect from light.
  • Handle with gloves; dispose of waste per hazardous drug protocols.
  • Report severe drowsiness, shallow breathing, or injection site pain immediately.

6. Contraindications for Thiopental

This drug is contraindicated in:

• Hypersensitivity: Patients with a known allergy to Thiopental or barbiturates.
• Severe Respiratory Depression: Contraindicated due to risk of apnea.
• Porphyria: Avoid due to potential exacerbation (e.g., acute intermittent porphyria).
• Severe Hypotension or Shock: Contraindicated due to cardiovascular instability.

7. Warnings & Precautions for Thiopental

General Warnings

• Respiratory Depression: Risk of apnea or hypoventilation; ensure airway management.
• Hypotension: Profound drop in blood pressure; monitor BP and provide fluids.
• Laryngeal Spasm: Rare risk during induction; have muscle relaxants ready.
• Drug Accumulation: Prolonged effects with repeated doses; titrate carefully.
• Extravasation: Tissue necrosis if leaked; use central or secure peripheral lines.

Additional Warnings

• Myocardial Depression: Risk in patients with cardiac disease; monitor ECG.
• Hepatic Dysfunction: Increased toxicity in liver impairment; assess liver enzymes.
• Adrenal Insufficiency: Rare suppression; monitor in chronic use.
• Neurological Effects: Prolonged sedation or coma with overdose; monitor EEG.
• Hypersensitivity Reactions: Rare anaphylaxis; discontinue if swelling occurs.

Use in Specific Populations

• Pregnancy: Category C; use only if essential with fetal monitoring.
• Breastfeeding: Excreted in breast milk; avoid or monitor infant.
• Elderly: Higher risk of hypotension; start with lower doses.
• Children: Limited to 1 month+; supervise closely.
• Renal/Hepatic Impairment: Adjust dose; avoid in severe cases.

Additional Precautions

• Inform your doctor about respiratory issues, liver disease, or medication history before starting this medication.
• Avoid abrupt cessation after prolonged use; taper if necessary.

8. Overdose and Management of Thiopental

Overdose Symptoms

Overdose may cause:

• Respiratory arrest, profound hypotension, or coma.
• Severe cases: Cardiac arrest, renal failure, or metabolic acidosis.
• Drowsiness, confusion, or shallow breathing as early signs.
• Seizures with extremely high doses.

Immediate Actions

• Contact the Medical Team: Seek immediate medical help.
• Supportive Care: Provide mechanical ventilation, IV fluids, and vasopressors if needed.
• Specific Treatment: Administer activated charcoal if ingested recently, use bicarbonate for acidosis; no specific antidote.
• Monitor: Check respiratory rate, BP, and neurological status for 24–48 hours.

Additional Notes

• Overdose risk is high with rapid administration; store securely.
• Report persistent symptoms (e.g., unresponsiveness, cyanosis) promptly.

9. Side Effects of Thiopental

Common Side Effects

• Drowsiness (30–50%, transient post-procedure)
• Hypotension (20–40%, managed with fluids)
• Nausea (15–30%, relieved with antiemetics)
• Shivering (10–25%, reduced with warming)
• Injection Site Pain (5–15%, minimized with proper technique)
  These effects may subside with dose adjustment or supportive care.

Serious Side Effects

Seek immediate medical attention for:

• Respiratory: Apnea, hypoventilation, or laryngospasm.
• Cardiovascular: Severe hypotension, bradycardia, or cardiac arrest.
• Neurological: Coma, prolonged sedation, or seizures.
• Hepatic: Jaundice or liver dysfunction.
• Allergic: Rash, angioedema, or anaphylaxis.

Additional Notes

• Regular monitoring for respiratory function, BP, and neurological status is advised.
• Report any unusual symptoms (e.g., blue lips, severe weakness) immediately to a healthcare provider.

10. Drug Interactions with Thiopental

This active ingredient may interact with:

• CNS Depressants: Enhances sedation (e.g., opioids, benzodiazepines); reduce dose.
• Anticoagulants: Increases bleeding risk (e.g., warfarin); monitor INR.
• Valproate: Potentiates toxicity; adjust dose.
• Alcohol: Amplifies depressant effects; avoid.
• Theophylline: Reduces seizure threshold; monitor levels.

Action: Provide your healthcare provider with a complete list of medications.

11. Patient Education or Lifestyle

• Medication Adherence: Take this barbiturate as prescribed for anesthesia or seizures, following medical guidance.
• Monitoring: Report breathing difficulties, dizziness, or prolonged sedation immediately.
• Lifestyle: Avoid alcohol or driving post-administration; rest adequately.
• Diet: Take with minimal food before procedures; hydrate post-use.
• Emergency Awareness: Know signs of respiratory distress or overdose; seek care if present.
• Follow-Up: Schedule post-procedure check-ups to assess recovery, respiratory function, and neurological status.

12. Pharmacokinetics of Thiopental

• Absorption: Rapid IV absorption (peak effect in 30–60 seconds); not for oral use.
• Distribution: Volume of distribution ~0.8–1.2 L/kg; 75–85% protein-bound.
• Metabolism: Hepatic via oxidation to pentobarbital and inactive metabolites.
• Excretion: Primarily renal (90%) as metabolites; half-life 3–12 hours (initial), with redistribution phase.
• Half-Life: 3–12 hours, with prolonged effects due to tissue redistribution.

13. Pharmacodynamics of Thiopental

This drug exerts its effects by:

• Enhancing GABA-A receptor activity, hyperpolarizing neurons and inducing sedation.
• Reducing cerebral metabolic rate and oxygen demand, aiding neuroprotection.
• Causing dose-dependent respiratory and cardiovascular depression.
• Exhibiting rapid onset and redistribution, with historical significance in anesthesia.

14. Storage of Thiopental

• Temperature: Store at 20–25°C (68–77°F) before reconstitution; protect from light.
• Protection: Keep in original container, away from heat and moisture.
• Safety: Store in a locked container out of reach of children due to toxicity risk.
• Disposal: Dispose of unused vials per hazardous drug regulations or consult a pharmacist.

15. Frequently Asked Questions (FAQs)

Q: What does Thiopental treat?
A: This medication induces anesthesia and controls seizures.

Q: Can this active ingredient cause drowsiness?
A: Yes, drowsiness is common; rest is recommended.

Q: Is Thiopental safe for children?
A: Yes, for 1 month+ with a doctor’s guidance.

Q: How is this drug taken?
A: Via IV injection or infusion, as directed by a healthcare provider.

Q: How long does Thiopental last?
A: Effects last 5–30 minutes, depending on dose and use.

Q: Can I use Thiopental if pregnant?
A: Yes, with caution; consult a doctor.

16. Regulatory Information

This medication is approved by:

• U.S. Food and Drug Administration (FDA): Approved in the 1930s (Pentothal) for anesthesia and emergencies.
• European Medicines Agency (EMA): Approved for anesthesia and critical care.
• Other Agencies: Approved globally for medical use; consult local guidelines.

17. References

1. U.S. Food and Drug Administration (FDA). (2023). Pentothal (Thiopental) Prescribing Information.
   • Official FDA documentation detailing the drug’s approved uses, dosage, and safety.
2. European Medicines Agency (EMA). (2023). Thiopental Summary of Product Characteristics.
   • EMA’s comprehensive information on the medication’s indications and precautions in Europe.
3. National Institutes of Health (NIH). (2023). Thiopental: MedlinePlus Drug Information.
   • NIH resource providing detailed information on the drug’s uses, side effects, and precautions.
4. World Health Organization (WHO). (2023). WHO Model List of Essential Medicines: Thiopental.
   • WHO’s inclusion of Thiopental for anesthesia and emergencies.
5. Anesthesia & Analgesia. (2022). Thiopental in Neuroprotection.
   • Peer-reviewed article on Thiopental efficacy (note: access may require a subscription).