Which statement best reflects the oral dose equivalence between chlorpromazine and loxapine? Specifically, 100 mg/day chlorpromazine is equivalent to how many mg loxapine.

Which statement best reflects the oral dose equivalence between chlorpromazine and loxapine? Specifically, 100 mg/day chlorpromazine is equivalent to how many mg loxapine.

• A. 20 mg loxapine
• B. 10 mg loxapine
• C. 40 mg loxapine
• D. 60 mg loxapine

Answer: (A)

Dose equivalence between antipsychotics is about comparing how potent each drug is in producing a similar antipsychotic effect. Loxapine is more potent per milligram than chlorpromazine, so a smaller amount of loxapine can achieve roughly the same effect as a larger amount of chlorpromazine. In practice, about 100 mg of chlorpromazine is considered roughly equivalent to 20 mg of loxapine. That means 20 mg of loxapine is the amount that best matches 100 mg of chlorpromazine. This is a guide for switching or comparing doses, and individual response and tolerability can shift the exact amount. The other options would imply potency ratios that don’t align with the standard conversion (for example, 10 mg would correspond to about 50 mg chlorpromazine, which is not the typical equivalence).

Dose equivalence between antipsychotics is about comparing how potent each drug is in producing a similar antipsychotic effect. Loxapine is more potent per milligram than chlorpromazine, so a smaller amount of loxapine can achieve roughly the same effect as a larger amount of chlorpromazine. In practice, about 100 mg of chlorpromazine is considered roughly equivalent to 20 mg of loxapine. That means 20 mg of loxapine is the amount that best matches 100 mg of chlorpromazine. This is a guide for switching or comparing doses, and individual response and tolerability can shift the exact amount. The other options would imply potency ratios that don’t align with the standard conversion (for example, 10 mg would correspond to about 50 mg chlorpromazine, which is not the typical equivalence).