Which organ is primarily responsible for the metabolism of sodium thiopental?

Which organ is primarily responsible for the metabolism of sodium thiopental?

• A. Kidney excretion unchanged
• B. Liver (P450) metabolism
• C. Brain metabolism
• D. Lung metabolism

Answer: (B)

The liver is the primary site for thiopental metabolism, mainly through the hepatic cytochrome P450 system. Thiopental is highly lipid-soluble, so it rapidly enters the brain to produce anesthesia, but its effects are terminated primarily by rapid hepatic biotransformation to inactive, more water-soluble metabolites. Redistribution to fat and muscle also helps end its action, but the key inactivation step is in the liver. The kidneys may excrete some metabolites, but they are not responsible for the main clearance. The brain and lungs do not significantly metabolize thiopental. In liver impairment, clearance drops and effects can be prolonged.

The liver is the primary site for thiopental metabolism, mainly through the hepatic cytochrome P450 system. Thiopental is highly lipid-soluble, so it rapidly enters the brain to produce anesthesia, but its effects are terminated primarily by rapid hepatic biotransformation to inactive, more water-soluble metabolites. Redistribution to fat and muscle also helps end its action, but the key inactivation step is in the liver. The kidneys may excrete some metabolites, but they are not responsible for the main clearance. The brain and lungs do not significantly metabolize thiopental. In liver impairment, clearance drops and effects can be prolonged.