Which factors are critical to consider in dosing meperidine to prevent toxicity?

Which factors are critical to consider in dosing meperidine to prevent toxicity?

• A. Hepatic Function and Urine pH
• B. Cardiac Function and Urine pH
• C. Renal Function and Urine pH
• D. Serum Potassium and Urine pH

Answer: (C)

Meperidine toxicity is driven by accumulation of its active metabolite, normeperidine, which is cleared by the kidneys. When renal function is reduced, normeperidine builds up and can cause CNS toxicity such as agitation, tremors, and seizures. Urine pH matters because meperidine and normeperidine are weak bases and their renal excretion is pH-dependent. In acidic urine, they are more readily excreted, reducing accumulation; in alkaline urine, excretion is reduced and risk of toxicity increases. So the most critical factors to consider in dosing to prevent toxicity are renal function and urine pH. Hepatic function can influence metabolism but is not the primary determinant of this toxicity risk, while cardiac function or potassium levels do not directly affect meperidine’s toxic potential.

Meperidine toxicity is driven by accumulation of its active metabolite, normeperidine, which is cleared by the kidneys. When renal function is reduced, normeperidine builds up and can cause CNS toxicity such as agitation, tremors, and seizures. Urine pH matters because meperidine and normeperidine are weak bases and their renal excretion is pH-dependent. In acidic urine, they are more readily excreted, reducing accumulation; in alkaline urine, excretion is reduced and risk of toxicity increases. So the most critical factors to consider in dosing to prevent toxicity are renal function and urine pH. Hepatic function can influence metabolism but is not the primary determinant of this toxicity risk, while cardiac function or potassium levels do not directly affect meperidine’s toxic potential.