Viibryd vs. Fluoxetine

See how Viibryd and Fluoxetine compare on approved uses, dosing, side effects, and cost.

Key Takeaways

  • Viibryd and fluoxetine both treat major depressive disorder but work differently, since Viibryd adds partial 5-HT1A receptor agonism to serotonin reuptake inhibition while fluoxetine works as a standard SSRI.

  • Fluoxetine has decades of safety data and is available as an inexpensive generic, while Viibryd has no widely available generic and costs substantially more per month.

  • Fluoxetine is FDA-approved for several conditions beyond depression, including OCD, panic disorder, and bulimia nervosa, while Viibryd is approved only for adult MDD.

Viibryd vs. Fluoxetine Drug Summary

Viibryd

Viibryd (vilazodone) is a serotonin partial agonist and reuptake inhibitor, or SPARI, approved to treat major depressive disorder in adults. It is taken once daily with food, starting at 10 mg and titrating up to a 40 mg maintenance dose over two weeks.

Fluoxetine

Fluoxetine is a selective serotonin reuptake inhibitor, or SSRI, approved for major depressive disorder, OCD, panic disorder, and bulimia nervosa. It is taken once daily, usually starting at 10 mg and increasing to a maintenance dose between 20 mg and 80 mg, with a once-weekly option available after stabilization.

Viibryd vs. Fluoxetine Side Effects

Viibryd

Most common
nausea (up to 23%)
insomnia (6% to 7%)
diarrhea (up to 28%)
vomiting (up to 5%)

Fluoxetine

Most common
nausea (up to 21%)
insomnia (up to 33%)
headache (up to 21%)
somnolence (up to 13%)

Viibryd vs. Fluoxetine Dosage

Viibryd

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 10 mg once daily Days 1-7
Maximum dose 40 mg once daily Day 15 onward
Dose changes 2 increases Every 7 days

Fluoxetine

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 10 mg once daily Week 1
Maximum dose 90 mg once weekly If needed
Dose changes 4 increases Every week

Viibryd vs. Fluoxetine Indications

Viibryd

Viibryd is FDA-approved to treat major depressive disorder in adults, using a mechanism that combines serotonin reuptake inhibition with partial 5-HT1A receptor agonism. It has not been studied enough in children to receive pediatric approval.

  • Major depressive disorder (MDD) in adults

  • Not approved for use in children or adolescents

  • Often considered for adults who did not respond well to standard SSRIs

  • No additional FDA-approved indications beyond MDD

Fluoxetine

Fluoxetine is FDA-approved for major depressive disorder in both adults and children as young as 8, along with OCD, panic disorder, and bulimia nervosa. It is also combined with olanzapine for treatment-resistant depression and bipolar depression.

  • Major depressive disorder in adults and children 8 and older

  • Obsessive-compulsive disorder in adults and children 7-17

  • Bulimia nervosa, panic disorder, and bipolar depression (with olanzapine)

  • Also used off-label for PMDD and binge eating disorder

Viibryd vs. Fluoxetine Pros and Cons

Viibryd

Viibryd's partial serotonin receptor agonism sets it apart from standard SSRIs, but it comes without a widely available generic and requires food for proper absorption. It is FDA-approved only for adult major depressive disorder, a narrower scope than many alternatives.

Pros

  • Partial 5-HT1A agonism may cause fewer sexual side effects than typical SSRIs

  • Straightforward once-daily dosing with a simple two-step titration

  • A distinct mechanism that may help patients who did not respond to SSRIs like fluoxetine

Cons

  • Must be taken with food or absorption drops significantly

  • No widely available generic, so cost is roughly $380 to $650 per month versus fluoxetine's $25 to $60

  • Only FDA-approved for adult MDD, a narrower indication than fluoxetine

Fluoxetine

Fluoxetine is one of the most studied and least expensive antidepressants available, with FDA approval spanning depression, OCD, panic disorder, and bulimia. Its long half-life offers dosing flexibility but can complicate switching to a different medication afterward.

Pros

  • Inexpensive generic pricing, roughly $25 to $60 per month versus Viibryd's $380 to $650

  • Approved for multiple conditions beyond depression, including OCD, panic disorder, and bulimia

  • Long track record since 1987 with extensive real-world safety data

Cons

  • Higher rates of insomnia and headache reported compared to Viibryd's label data

  • Long half-life metabolite can linger for weeks, complicating a switch to another antidepressant

  • Sexual dysfunction is a well-known and common issue with SSRIs like fluoxetine

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