Methohexital Sodium

• Methohexital Sodium, a barbiturate, enhances GABA action causing rapid sedation with short duration.
• It is used for anesthesia induction and short surgical or diagnostic procedures.

Chemical Formula:

• C₁₄H₁₇N₂NaO₃

Mechanism of Action:

• Potentiates GABA-A receptors
• Increases Cl⁻ influx → CNS depression
• Rapid onset due to high lipid solubility

Uses of Methohexital Sodium:

• Induction of anesthesia
• Brief surgical/dental procedures
• Electroconvulsive therapy (ECT)

Side Effects of Methohexital Sodium:

• Myoclonic movements
• Apnea
• Hypotension
• Reflex tachycardia

SAR of Methohexital:

1. Barbituric acid core (pyrimidine-2,4,6-trione):

   • Essential for CNS depressant activity.

2. 5,5-disubstitution:

   • Lipophilic groups (1-methyl, 1-hexenyl) increase lipid solubility → rapid onset and short duration.

3. Unsaturated side chain:

   • Increases onset speed and decreases duration (due to redistribution).

4. N-substitution:

   • Methylation of N1 may affect metabolic profile and lipid solubility.

5. Sodium salt form:

   • Increases aqueous solubility for IV use.

Synthesis of Methohexital:

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