Desvenlafaxine Formulation
No, there is no immediate-release formulation of desvenlafaxine available—it is only manufactured as an extended-release tablet for once-daily oral administration. 1
Formulation Details
Desvenlafaxine is formulated exclusively as an extended-release tablet containing 25 mg, 50 mg, or 100 mg of desvenlafaxine (equivalent to 38 mg, 76 mg, or 152 mg of desvenlafaxine succinate, respectively). 1
The extended-release formulation is designed specifically for once-daily dosing, which distinguishes it from its parent compound venlafaxine that was originally available in both immediate-release (requiring twice-daily dosing) and extended-release formulations. 2, 3
Pharmacokinetic Advantages of Extended-Release Formulation
The extended-release formulation achieves steady-state plasma concentrations within 4 to 5 days and has a half-life of approximately 10 hours, supporting once-daily administration. 4, 3
Research demonstrates that desvenlafaxine absorption from the extended-release formulation is rate-limited by dissolution due to the formulation design, which provides controlled drug release throughout the gastrointestinal tract. 5
The extended-release design helps mitigate the pH-dependent permeability variations that would otherwise affect absorption, as desvenlafaxine permeability increases approximately 13-fold when pH increases from 5.5 to 7.4. 5
Clinical Implications
The recommended therapeutic dose is 50 mg once daily, with no additional therapeutic benefit demonstrated at doses exceeding 50 mg/day, though doses up to 100 mg may be used. 3
The extended-release formulation offers convenient once-daily dosing with reduced risk for pharmacokinetic drug interactions compared to other antidepressants, as desvenlafaxine is metabolized primarily via glucuronidation rather than through cytochrome P450 enzymes. 4, 3