Differences Between Desvenlafaxine Succinate and Desvenlafaxine Fumarate
Desvenlafaxine succinate and desvenlafaxine fumarate differ primarily in their salt formulation, which affects pharmacokinetics, but both contain the same active metabolite (O-desmethylvenlafaxine) with identical therapeutic effects.
Key Differences
Salt Formulation
- Desvenlafaxine succinate: The succinate salt monohydrate of O-desmethylvenlafaxine 1
- Desvenlafaxine fumarate: The fumarate salt of the same active metabolite
Regulatory Status
- Desvenlafaxine succinate: FDA-approved in 2008 for treatment of major depressive disorder 1, 2
- Desvenlafaxine fumarate: Less commonly used formulation with the same active ingredient
Pharmacokinetic Properties
Both formulations contain the same active metabolite (O-desmethylvenlafaxine), which is the major active metabolite of venlafaxine. However, the different salt forms may affect:
- Absorption rates
- Bioavailability
- Steady-state concentrations
- Excretion profiles
Clinical Implications
Therapeutic Effects
- Both formulations work as serotonin-norepinephrine reuptake inhibitors (SNRIs) 1
- Both have the same mechanism of action in treating depression
- Both demonstrate similar efficacy in managing major depressive disorder
Dosing Considerations
- Desvenlafaxine succinate:
Metabolism and Drug Interactions
Both formulations share these advantages:
- Minimal metabolism via CYP450 pathway 2
- Weak inhibitor of CYP2D6 2
- Reduced risk for pharmacokinetic drug interactions compared to other SNRIs 3
- Primarily excreted in urine 2
Clinical Advantages of Desvenlafaxine (Both Formulations)
- Once-daily dosing at effective doses 4
- Achievement of steady-state plasma concentrations within 4-5 days 3
- Minimal drug-drug interactions due to limited CYP450 metabolism 2, 4
- No need for extensive dose titration to achieve therapeutic efficacy 1
Side Effect Profile
Both formulations share similar side effect profiles:
- Nausea is the most common adverse effect 1, 2
- Other common side effects include dizziness, headache, insomnia, and dry mouth
- Potential for discontinuation symptoms with cessation of treatment 1
Practical Considerations
- The clinical decision between these two salt forms would rarely be significant
- Prescribing decisions should be based on:
- Availability in your region
- Insurance coverage
- Patient's previous response to either formulation
- Cost considerations
In clinical practice, the difference between these two salt formulations is minimal in terms of efficacy and safety for treating major depressive disorder, with both containing the same active metabolite of venlafaxine.