BLACK BOX WARNING
- increased mortality in elderly patients with dementia-related psychosis
pimavanserin
Brand: Nuplazid
⚠ BBW Beers Criteria Prototype Drug
Drug Class: atypical antipsychotic
Drug Family: antipsychotic
Subclass: selective serotonin 5-HT2A inverse agonist/antagonist
Organ Systems: cns
Mechanism of Action
First antipsychotic with no dopamine receptor activity; acts exclusively via 5-HT2A receptor inverse agonism/antagonism. This mechanism reduces hallucinations and delusions without worsening the motor symptoms of Parkinson's disease, unlike dopamine antagonist antipsychotics.
5-HT2A receptor (inverse agonist/antagonist)5-HT2C receptor (inverse agonist)
Indications
- hallucinations and delusions associated with Parkinson's disease psychosis
Contraindications
- concurrent strong CYP3A4 inducers
Adverse Effects
Common
- peripheral edema
- confusion
- hallucinations (paradoxically in some patients)
- gait disturbance
Serious
- QT prolongation
- increased mortality in elderly dementia patients
- somnolence
Pharmacokinetics (ADME)
| Absorption | well absorbed orally; not significantly affected by food |
| Distribution | protein binding ~95%; large Vd |
| Metabolism | primarily CYP3A4 and CYP3A5; active metabolite AC-279 |
| Excretion | primarily fecal |
| Half-life | 57 hours (parent); 200 hours (active metabolite); effective half-life ~3 weeks |
| Onset | 4-6 weeks for significant therapeutic effect |
| Peak | 6 hours |
| Duration | once-daily dosing |
| Protein Binding | 95% |
| Vd | not well characterized |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| strong CYP3A4 inducers (rifampin, carbamazepine) | contraindicated; decreases pimavanserin levels by ~90% | contraindicated |
| strong CYP3A4 inhibitors (ketoconazole) | reduce dose to 10 mg; increases exposure | major |
| QT-prolonging agents | additive QT prolongation | major |
Nursing Considerations
- Pimavanserin is the only antipsychotic that does not worsen motor symptoms in Parkinson's disease; it is the drug of choice when antipsychotic treatment is needed in PD.
- Obtain baseline ECG for QT assessment; pimavanserin prolongs QT interval — monitor in patients with cardiac disease or on other QT-prolonging drugs.
- Onset of therapeutic effect may require 4-6 weeks; manage caregiver and family expectations about timeline for symptom improvement.
- Due to the very long effective half-life (weeks from active metabolite), drug interactions and adverse effects may persist long after discontinuation.
Clinical Pearls
- Pimavanserin represents the first mechanistically distinct antipsychotic in decades; by avoiding dopamine receptor blockade entirely, it addresses a critical unmet need — treating psychosis in conditions where dopamine blockade is harmful (Parkinson's disease).
- Despite its clean mechanism, pimavanserin carries the same dementia-related psychosis BBW as other antipsychotics, reflecting the class-wide trial finding of increased mortality in elderly patients with dementia.
Safety Profile
Pregnancy use-with-caution
Lactation avoid
Renal Adjustment Not required
Hepatic Adjustment Required
TDM Not required
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.