Pristiq vs. Fluoxetine
See how Pristiq and Fluoxetine compare on approved uses, dosing, side effects, and cost.
Key Takeaways
Pristiq is an SNRI with a single maintenance dose, while fluoxetine is an SSRI that offers more flexible dosing, including a once-weekly option.
Fluoxetine covers a much broader range of FDA-approved uses, including OCD, bulimia, and pediatric depression, while Pristiq is approved only for adult MDD.
Both carry a boxed warning for suicidal thinking in young people and should never be combined with MAOIs due to serotonin syndrome risk.
Pristiq vs. Fluoxetine Drug Summary
Pristiq
Pristiq (desvenlafaxine) is a serotonin-norepinephrine reuptake inhibitor (SNRI) approved to treat major depressive disorder in adults. It comes as an extended-release tablet taken once daily, with 50 mg serving as both the starting and maintenance dose.
Fluoxetine
Fluoxetine is a selective serotonin reuptake inhibitor (SSRI) approved for major depressive disorder, OCD, bulimia nervosa, panic disorder, and certain bipolar depression regimens. It is taken once daily, starting at a lower dose and increasing over time, with an option for once-weekly maintenance dosing.
Pristiq vs. Fluoxetine Side Effects
Pristiq
Fluoxetine
Pristiq vs. Fluoxetine Dosage
Pristiq
Fluoxetine
| STAGE | DOSE | WHEN |
| Starting dose | 50 mg once daily | Day 1 onward |
| Maximum dose | 50 mg once daily | Same as starting |
| Dose changes | None | Fixed dose |
| STAGE | DOSE | WHEN |
| Starting dose | 10 mg once daily | Week 1 |
| Maximum dose | 20 mg once daily | Week 2 onward |
| Dose changes | 1 increase | Every week |
Pristiq
| STAGE | DOSE | WHEN |
| Starting dose | 50 mg once daily | Day 1 onward |
| Maximum dose | 50 mg once daily | Same as starting |
| Dose changes | None | Fixed dose |
Fluoxetine
| STAGE | DOSE | WHEN |
| Starting dose | 10 mg once daily | Week 1 |
| Maximum dose | 20 mg once daily | Week 2 onward |
| Dose changes | 1 increase | Every week |
Pristiq vs. Fluoxetine Indications
Pristiq
Pristiq is FDA-approved solely for treating major depressive disorder in adults. It is not approved for pediatric use and requires dosage adjustments in patients with severe kidney impairment.
FDA-approved for major depressive disorder (MDD) in adults
Not approved for use in children or adolescents
Not approved for use without adjustment in severe kidney disease
Fluoxetine
Fluoxetine is approved for a wider range of conditions, including OCD, bulimia nervosa, panic disorder, and bipolar depression with olanzapine. It's also approved for children and teens with depression or OCD.
FDA-approved for major depressive disorder in adults and children 8-18
Approved for OCD in adults and children 7-17
Approved for bulimia nervosa and panic disorder in adults
Pristiq vs. Fluoxetine Pros and Cons
Pristiq
Pristiq's single 50 mg dose works as both the starting and long-term dose, which simplifies treatment for some patients. Its narrower FDA approval and higher price compared to older generics are real trade-offs to weigh.
Pros
Single 50 mg dose serves as both starting and maintenance therapy
SNRI action on norepinephrine may help when SSRIs alone haven't worked
Not metabolized through CYP2D6, avoiding that interaction pathway
Generic desvenlafaxine available for lower-cost alternative to brand
Cons
Only FDA-approved for adults with major depressive disorder
Higher rates of dry mouth, hyperhidrosis, and constipation than SSRIs
Typically costs more, roughly $400 to $543 per month before insurance
No pediatric or off-label indications established in FDA labeling
Fluoxetine
Fluoxetine's decades of use and broad approval list make it a versatile option across several psychiatric conditions. Its low generic cost is a major advantage, though reaching a therapeutic dose takes more titration steps than Pristiq.
Pros
Approved for a wide range of conditions, from OCD to bulimia to panic
Available as capsule, tablet, or oral solution for flexible use
Decades of generic availability keep costs low, roughly $25 to $60 per month
Once-weekly maintenance dosing option available for some patients
Cons
Requires titration across several dose steps to reach a therapeutic level
Long-acting metabolite can prolong drug interactions after stopping
Contraindicated with pimozide and thioridazine due to QT prolongation risk
Insomnia is more common than with Pristiq
Common Symptoms and Related Diseases You Can Explore
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