Which drugs can decrease benzodiazepine metabolism, increasing risk of toxicity?

Which drugs can decrease benzodiazepine metabolism, increasing risk of toxicity?

• A. Acetaminophen
• B. Ibuprofen
• C. Vitamin C
• D. Verapamil and diltiazem

Answer: (D)

Drugs that slow the breakdown of benzodiazepines in the liver can raise their levels and increase the risk of toxicity. Many benzodiazepines are metabolized by the enzyme CYP3A4. When another drug inhibits this enzyme, clearance is reduced, leading to higher plasma concentrations, more pronounced sedation, and potential respiratory depression or overdose. Verapamil and diltiazem are calcium channel blockers known to inhibit CYP3A4, so their combination with benzodiazepines that rely on this pathway can markedly raise exposure and toxicity risk. The other listed drugs don’t significantly block this metabolic route, so they don’t create the same interaction. (Some benzodiazepines are cleared mainly by glucuronidation instead of CYP3A4, so interactions vary among agents, but the key concept remains that CYP3A4 inhibitors elevate benzodiazepine exposure.)

Drugs that slow the breakdown of benzodiazepines in the liver can raise their levels and increase the risk of toxicity. Many benzodiazepines are metabolized by the enzyme CYP3A4. When another drug inhibits this enzyme, clearance is reduced, leading to higher plasma concentrations, more pronounced sedation, and potential respiratory depression or overdose. Verapamil and diltiazem are calcium channel blockers known to inhibit CYP3A4, so their combination with benzodiazepines that rely on this pathway can markedly raise exposure and toxicity risk. The other listed drugs don’t significantly block this metabolic route, so they don’t create the same interaction. (Some benzodiazepines are cleared mainly by glucuronidation instead of CYP3A4, so interactions vary among agents, but the key concept remains that CYP3A4 inhibitors elevate benzodiazepine exposure.)