Using Prozac (Fluoxetine) and Ingrezza (Valbenazine) Together
Yes, it is safe to use fluoxetine (Prozac) and valbenazine (Ingrezza) together—these medications have distinct, non-overlapping mechanisms with no clinically significant pharmacokinetic interactions. 1
Why This Combination Is Safe
Valbenazine and fluoxetine work through completely separate pathways: valbenazine reduces dopamine release via VMAT2 inhibition while fluoxetine increases serotonin availability through selective serotonin reuptake inhibition. 1 Although fluoxetine has moderate effects on CYP2D6 metabolism, valbenazine's metabolic pathway does not create clinically significant interactions with this enzyme system. 1
Key Monitoring Parameters
Watch for Serotonin Syndrome (Low Risk with This Combination Alone)
- Monitor for serotonin syndrome symptoms if other serotonergic agents are added to the regimen: mental status changes, neuromuscular hyperactivity (myoclonus, hyperreflexia), and autonomic hyperactivity (diaphoresis, diarrhea). 1
- These symptoms typically arise within 24-48 hours after combining multiple serotonergic medications. 1
- The risk with fluoxetine and valbenazine alone is minimal since valbenazine is not serotonergic. 1
Standard SSRI Monitoring
- Continue routine psychiatric monitoring for behavioral activation, particularly during the first month of fluoxetine treatment or with dose increases. 1
- This is standard practice for any patient on SSRIs and not specific to the combination. 2
Common Pitfalls to Avoid
Do Not Confuse Valbenazine with Antipsychotics
The concern about QT prolongation that applies to antipsychotics does not apply to valbenazine—it is not an antipsychotic and did not demonstrate clinically significant QT prolongation in clinical trials. 1 This is a critical distinction since fluoxetine itself carries FDA warnings about QT prolongation in certain populations (CYP2D6 poor metabolizers, congenital long QT syndrome). 2
Do Not Discontinue Valbenazine Unnecessarily
- Avoid unnecessary discontinuation of valbenazine, as tardive dyskinesia symptoms will re-emerge if the medication is stopped. 1
- Plan for long-term treatment if TD improvement is achieved with valbenazine. 1 3
Clinical Context
Valbenazine is the first FDA-approved medication specifically for tardive dyskinesia, with clinically significant efficacy at 80 mg/day (effect size d=0.90). 3 When patients with TD require concurrent antidepressant therapy, fluoxetine can be safely prescribed alongside valbenazine without dose adjustments or special precautions beyond standard monitoring for each individual medication. 1