Ibuprofen does not impair antipyrine clearance.

Area of Science:

• Pharmacokinetics
• Drug Metabolism
• Clinical Pharmacology

Background:

• Antipyrine is a common marker for assessing drug-metabolizing enzyme activity in humans.
• Understanding drug interactions is crucial for safe therapeutic use.

Purpose of the Study:

• To investigate the impact of therapeutic ibuprofen doses on antipyrine pharmacokinetics.
• To determine if ibuprofen affects antipyrine distribution and clearance in healthy volunteers.

Main Methods:

• Healthy volunteers received intravenous antipyrine.
• Antipyrine was administered alone and concurrently with ibuprofen (1.6-2.4 Gm/day).
• Plasma concentrations of antipyrine and ibuprofen were measured over 24 hours.

Main Results:

• No significant differences were observed in antipyrine's volume of distribution (0.69 L/kg).
• Elimination half-life (12.2 vs. 12.5 hours) and total metabolic clearance (0.69 vs. 0.70 mL/min/kg) remained unchanged.
• Plasma ibuprofen levels averaged 22 µg/mL, confirming compliance.

Conclusions:

• Ibuprofen, at therapeutic doses, does not impair the metabolic clearance of antipyrine.
• Ibuprofen does not affect antipyrine's distribution or elimination half-life in humans.
• Antipyrine remains a reliable index of drug oxidizing capacity even with concurrent ibuprofen use.