NAPLEX (North American Pharmacist Licensure Examination) Practice Exam

What should be reduced by at least 25% to account for cross tolerance in opioid dosing conversions?

1. PO dose only

2. IV/IM dose only

3. Equivalent dose

4. Initial dose

The correct answer is: Equivalent dose

Cross tolerance refers to the phenomenon where a person develops a tolerance to one type of opioid, making them less sensitive to its effects. This requires an increase in dosage to achieve the same level of pain relief. When converting to a different opioid, a reduction of at least 25% is needed to account for this cross tolerance. Therefore, the correct answer is C, equivalent dose, as it takes into account the cross tolerance in determining the proper dosage amount. A, B, and D are incorrect options. Reducing the PO dose only (A) does not take into account the reduced sensitivity due to cross tolerance and may result in an insufficient dosage. The IV/IM dose only (B) does not address the issue of cross tolerance at all. Similarly, the initial dose (D) does not account for cross tolerance and may lead to a potentially harmful dosage.