Which urine pH accelerates meperidine excretion?

Which urine pH accelerates meperidine excretion?

• A. pH Above 7
• B. pH Below 5
• C. pH Around 6 to 7
• D. pH Not Affected

Answer: (B)

Ion trapping in the kidney determines how fast a drug is excreted based on urine pH. Meperidine is a weak base, so in acidic urine it becomes protonated to a charged form. This ionized form cannot readily cross renal tubular membranes, so it stays in the filtrate and is excreted more quickly. In alkaline urine, the drug remains mostly non-ionized and can be reabsorbed, reducing excretion. Thus, acidic urine accelerates meperidine excretion, with pH below 5 being the most effective cited condition.

Ion trapping in the kidney determines how fast a drug is excreted based on urine pH. Meperidine is a weak base, so in acidic urine it becomes protonated to a charged form. This ionized form cannot readily cross renal tubular membranes, so it stays in the filtrate and is excreted more quickly. In alkaline urine, the drug remains mostly non-ionized and can be reabsorbed, reducing excretion.

Thus, acidic urine accelerates meperidine excretion, with pH below 5 being the most effective cited condition.