Venlafaxine Half-Life
Venlafaxine has an elimination half-life of approximately 5 hours (±2 hours), while its active metabolite O-desmethylvenlafaxine (ODV) has a half-life of approximately 11 hours (±2 hours). 1
Pharmacokinetic Details
The mean steady-state elimination half-life for venlafaxine is 5 ± 2 hours and for its active metabolite ODV is 11 ± 2 hours, based on FDA labeling data 1
Steady-state plasma concentrations of both venlafaxine and ODV are attained within 3 days of multiple-dose therapy 1
The elimination half-life ranges from 3-4 hours for venlafaxine and approximately 10 hours for O-desmethylvenlafaxine across multiple studies 2, 3, 4
Clinical Implications for Dosing
Because of venlafaxine's short elimination half-life, the immediate-release formulation may require twice- or thrice-daily dosing to maintain therapeutic levels 5
The extended-release formulations of venlafaxine (and its metabolite desvenlafaxine) have sufficiently long elimination half-lives to permit single daily dosing 5
When equal daily doses are administered as either twice-daily or three-times-daily regimens, drug exposure (AUC) and plasma level fluctuation of both venlafaxine and ODV are comparable between regimens 1
Special Populations Affecting Half-Life
In hepatic cirrhosis: Venlafaxine elimination half-life is prolonged by approximately 30%, and in severe cirrhosis (Child-Pugh B), the half-life can be approximately twice as long as in normal subjects 1
In renal impairment: Venlafaxine elimination half-life is prolonged by approximately 50% in patients with GFR 10-70 mL/min, and by approximately 180% in dialysis patients 1
In dialysis patients: ODV elimination half-life is prolonged by approximately 142% compared to normal subjects, requiring dosage adjustment 1
Context for OCD Treatment
For treatment-resistant OCD specifically, the pharmacokinetic profile remains the same regardless of the indication, as the half-life is a fixed drug property 1
In OCD treatment studies, venlafaxine was used at a mean dose of 232.2 mg/day (range 37.5-375 mg/day), with 69.2% of patients showing sustained response, including 75.9% of those resistant to prior SSRI trials 6