Which of the following drugs has a high therapeutic index?

Which of the following drugs has a high therapeutic index?

A. Lithium

B. None of the above

C. Phenytoin

D. Carbamazepine

E. Gabapentin

E. Gabapentin

The therapeutic index is a comparison of the amount of a therapeutic agent that causes the therapeutic effect to the amount that causes death. A drug with a narrow therapeutic range usually needs to have its dosage adjusted according to measurements of the actual blood levels achieved in the person taking it.

Important drugs used in psychiatry with a narrow therapeutic index (and therefore require monitoring) are:-
• Carbamazepine
• Lithium
• Phenytoin