Phentermine Detection in Urine Drug Testing

Detection and Elimination

• More than 90% of phentermine is excreted unchanged in the urine through glomerular filtration and tubular secretion, making urine the primary route of elimination, according to the Centers for Disease Control and Prevention (CDC) guidelines 1
• Renal clearance of phentermine is reduced substantially in persons with renal insufficiency, requiring dosage adjustments and significantly prolonging detection times, as recommended by the CDC 1
• Patients with impaired kidney function will have markedly extended detection windows beyond the typical 3-4 day period due to decreased urinary elimination, as stated in the CDC guidelines 1
• For patients with impaired renal function, expect detection for 5-7 days or longer depending on severity of impairment, according to the CDC recommendations 1
• Consider that elimination half-life is prolonged in renal insufficiency, as noted in the CDC guidelines 1
• Do not assume standard 3-4 day detection in patients with any degree of renal impairment - these patients require individualized assessment based on creatinine clearance, as advised by the CDC 1