Oxazepam disposition in uremic patients

Area of Science:

• Pharmacology
• Clinical Pharmacy

Background:

• Oxazepam pharmacokinetics can be altered in patients with kidney dysfunction.
• Understanding drug metabolism and excretion in uremia is crucial for safe dosing.

Purpose of the Study:

• To investigate the pharmacokinetics of oxazepam in patients with uremia.
• To assess the impact of renal impairment on oxazepam metabolism and elimination.

Main Methods:

• Pharmacokinetic analysis of oxazepam in 13 uremic patients.
• Measurement of plasma concentrations, half-life, and clearance.
• Quantification of conjugated metabolites and assessment of urinary and fecal recovery.

Main Results:

• Oxazepam apparent terminal half-life was significantly prolonged (24-91 hours) in uremic patients compared to healthy volunteers.
• Conjugated oxazepam metabolites accumulated significantly (5-50 times parent compound) and persisted for days.
• Renal clearance of conjugated oxazepam correlated with creatinine clearance; urinary recovery was 18-57% over 5 days.
• Enterohepatic recycling was suggested but not quantitatively significant.

Conclusions:

• Uremia prolongs oxazepam's half-life primarily due to metabolite accumulation.
• While enterohepatic recycling may occur, it's not a major contributor to oxazepam pharmacokinetics in uremia.
• Oxazepam clearance appears normal, but metabolite accumulation warrants consideration in uremic patients.