In the same set of equivalence data, 1 mg of risperidone is equivalent to how many milligrams of the reference drug (chlorpromazine)?

• A. 75 mg
• B. 150 mg
• C. 25 mg
• D. 350 mg

Answer: (B)

The key idea is using chlorpromazine equivalents to compare antipsychotics. In the provided equivalence data, 1 mg of risperidone corresponds to 150 mg of chlorpromazine. That means the chlorpromazine-equivalent dose for 1 mg risperidone is 150 mg. So the CPZ dose that matches 1 mg risperidone is 150 mg.

This conversion helps when switching drugs or interpreting doses across different antipsychotics. If you had a different risperidone dose, you’d multiply by 150 to get the chlorpromazine-equivalent dose (or divide by 150 to go the other way). Remember, actual dosing should follow current guidelines and patient factors, since equivalence tables are guidelines.