Pristiq (Desvenlafaxine Succinate) Available Formulations
Pristiq is commercially available as extended-release tablets in three strengths: 25 mg, 50 mg, and 100 mg. 1
Tablet Specifications
25 mg Tablets
- Appearance: Tan colored, round, biconvex tablets
- Markings: Debossed with 'L634' on one side, plain on the other
- Active ingredient: Contains 38 mg desvenlafaxine succinate (equivalent to 25 mg desvenlafaxine base) 1
50 mg Tablets
- Appearance: Light pink colored, round, biconvex tablets
- Markings: Debossed with 'L349' on one side, plain on the other
- Active ingredient: Contains 76 mg desvenlafaxine succinate (equivalent to 50 mg desvenlafaxine base) 1
100 mg Tablets
- Appearance: Dark brown to red colored, round, biconvex tablets
- Markings: Debossed with 'L350' on one side, plain on the other
- Active ingredient: Contains 152 mg desvenlafaxine succinate (equivalent to 100 mg desvenlafaxine base) 1
Dosing Considerations
- The recommended therapeutic dose is 50 mg once daily, as clinical trials demonstrated clear efficacy at this dose with no additional therapeutic benefit at higher doses (100-400 mg/day) 2, 3, 4
- The 50-100 mg/day range is considered therapeutic, though doses above 50 mg carry significantly higher risk of side effects without added efficacy 3
- Once-daily dosing is a key advantage of desvenlafaxine, with steady-state plasma concentrations achieved within 4-5 days 2
- No extensive titration is required to achieve therapeutic efficacy, unlike venlafaxine 3, 5
Storage Requirements
- Store at 20°C to 25°C (68°F to 77°F)
- Excursions permitted to 15°C to 30°C (59°F to 86°F) per USP Controlled Room Temperature guidelines 1
Key Pharmacologic Distinctions
- Desvenlafaxine does not significantly inhibit CYP2D6, making it preferable in patients taking tamoxifen or other CYP2D6 substrates 6
- Linear pharmacokinetics with low protein binding and a half-life of approximately 10 hours 7
- Metabolism primarily via glucuronidation rather than CYP450 enzymes, reducing drug-drug interaction risk 3, 7, 5