using higher dose of magnesium sulfate together with a CNS depressant.sodium sulfate/potassium sulfate/magnesium sulfatesodium sulfate/potassium sulfate/magnesium sulfate increases toxicity of pimavanserin by QTc interval. Use Caution/Monitor. Consider predose and post-colonoscopy ECGs in patients at increased risk of serious cardiac arrhythmias. .sodium sulfate/potassium sulfate/magnesium sulfate increases effects of pimavanserin by unknown mechanism. Use Caution/Monitor. Closely monitor for evidence of enhanced CNS depression when using higher dose of magnesium sulfate together with a CNS depressant.St John's WortSt John's Wort will decrease the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration if possible. Monitor for reduced pimavanserin efficacy. An increase in pimavanserin dosage may be needed.stiripentolstiripentol, pimavanserin. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP3A4 inhibitor and inducer. Monitor CYP3A4 substrates coadministered with stiripentol for increased or decreased effects. CYP3A4 substrates may require dosage adjustment.sumatriptansumatriptan, pimavanserin. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).sumatriptan intranasalsumatriptan intranasal, pimavanserin. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).tazemetostattazemetostat will decrease the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.tecovirimattecovirimat will decrease the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.tranylcyprominetranylcypromine, pimavanserin. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).triclabendazoletriclabendazole and pimavanserin both increase QTc interval. Use Caution/Monitor.valbenazinevalbenazine and pimavanserin both increase QTc interval. Use Caution/Monitor.venlafaxinevenlafaxine, pimavanserin. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).vilazodonevilazodone, pimavanserin. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).voclosporinvoclosporin, pimavanserin. Either increases effects of the other by QTc interval. Use Caution/Monitor.zolmitriptanzolmitriptan, pimavanserin. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).Minor (6)acetazolamideacetazolamide will increase the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.anastrozoleanastrozole will increase the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.azithromycinazithromycin increases toxicity of pimavanserin by QTc interval. Minor/Significance Unknown.chloroquinechloroquine increases toxicity of pimavanserin by QTc interval. Minor/Significance Unknown.cyclophosphamidecyclophosphamide will increase the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.larotrectiniblarotrectinib will increase the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.abametapirSerious - Use Alternative (1)abametapir will increase the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP3A4 substrates. If not feasible, avoid use of abametapir.acetazolamideMinor (1)acetazolamide will increase the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.adagrasibSerious - Use Alternative (1)adagrasib, pimavanserin. Either increases effects of the other by QTc interval. Avoid or Use Alternate Drug. Each drug prolongs the QTc interval, which may increased the risk of Torsade de pointes, other serious arryhthmias, and sudden death. If coadministration unavoidable, more frequent monitoring is recommended for such patients.albuterolMonitor Closely (1)albuterol and pimavanserin both increase QTc interval. Use Caution/Monitor.alfuzosinMonitor Closely (1)pimavanserin and alfuzosin both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (1)alfuzosin and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.almotriptanMonitor Closely (1)almotriptan, pimavanserin. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).amiodaroneSerious - Use Alternative (1)pimavanserin and amiodarone both increase QTc interval. Avoid or Use Alternate Drug. Coadministration may increase the risk of QT prolongation and cardiac arrhythmia.amisulprideSerious - Use Alternative (1)amisulpride and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug. ECG monitoring is recommended if coadministered.amobarbitalSerious - Use Alternative (1)amobarbital will decrease the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.anagrelideSerious - Use Alternative (1)pimavanserin and anagrelide both increase QTc interval. Avoid or Use Alternate Drug. Coadministration may increase the risk of QT prolongation and cardiac arrhythmia.anastrozoleMinor (1)anastrozole will increase the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.apalutamideSerious - Use Alternative (1)apalutamide will decrease the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP3A4 inducer, with drugs that are CYP3A4 substrates can result in lower exposure to these medications. Avoid or substitute another drug for these medications when possible. Evaluate for loss of therapeutic effect if medication must be coadministered. Adjust dose according to prescribing information if needed.apomorphineSerious - Use Alternative (1)apomorphine and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.arformoterolMonitor Closely (1)arformoterol and pimavanserin both increase QTc interval. Use Caution/Monitor.aripiprazoleSerious - Use Alternative (1)aripiprazole and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.arsenic trioxideSerious - Use Alternative (1)pimavanserin and arsenic trioxide both increase QTc interval. Avoid or Use Alternate Drug. Coadministration may increase the risk of QT prolongation and cardiac arrhythmia.artemetherSerious - Use Alternative (1)artemether and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.artemether/lumefantrineSerious - Use Alternative (1)pimavanserin and artemether/lumefantrine both increase QTc interval. Avoid or Use Alternate Drug. Coadministration may increase the risk of QT prolongation and cardiac arrhythmia.asenapineSerious - Use Alternative (1)pimavanserin and asenapine both increase QTc interval. Avoid or Use Alternate Drug. Coadministration may increase the risk of QT prolongation and cardiac arrhythmia.asenapine transdermalSerious - Use Alternative (1)asenapine transdermal and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.atazanavirSerious - Use Alternative (1)atazanavir will increase the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Decrease dose to 17 mg/day if pimavanserin is coadministered with strong CYP3A4 inhibitors.atomoxetineSerious - Use Alternative (1)atomoxetine and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.azithromycinMinor (1)azithromycin increases toxicity of pimavanserin by QTc interval. Minor/Significance Unknown.bedaquilineSerious - Use Alternative (1)bedaquiline and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.benzhydrocodone/acetaminophenSerious - Use Alternative (1)benzhydrocodone/acetaminophen, pimavanserin. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.bosentanMonitor Closely (1)bosentan will decrease the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration if possible. Monitor for reduced pimavanserin efficacy. An increase in pimavanserin dosage may be needed.brexanoloneMonitor Closely (1)brexanolone, pimavanserin. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.buprenorphineSerious - Use Alternative (1)buprenorphine and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.buprenorphine buccalSerious - Use Alternative (1)buprenorphine buccal and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.buprenorphine subdermal implantSerious - Use Alternative (1)buprenorphine subdermal implant and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.buprenorphine transdermalSerious - Use Alternative (1)buprenorphine transdermal and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.buprenorphine, long-acting injectionMonitor Closely (1)pimavanserin increases toxicity of buprenorphine, long-acting injection by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of buprenorphine and benzodiazepines or other CNS depressants increases risk of adverse reactions including overdose, respiratory depression, and death. Cessation of benzodiazepines or other CNS depressants is preferred in most cases. In some cases, monitoring at a higher level of care for tapering CNS depressants may be appropriate. In others, gradually tapering a patient off of a prescribed benzodiazepine or other CNS depressant or decreasing to the lowest effective dose may be appropriate.Serious - Use Alternative (1)buprenorphine, long-acting injection and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.carbamazepineMonitor Closely (1)carbamazepine will decrease the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration if possible. Monitor for reduced pimavanserin efficacy. An increase in pimavanserin dosage may be needed.cenobamateMonitor Closely (2)cenobamate, pimavanserin. Either increases effects of the other by sedation. Use Caution/Monitor. cenobamate will decrease the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP3A4 substrate, as needed, when coadministered with cenobamate.ceritinibSerious - Use Alternative (2)ceritinib and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug. ceritinib will increase the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.chloramphenicolSerious - Use Alternative (1)chloramphenicol will increase the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.chloroquineMinor (1)chloroquine increases toxicity of pimavanserin by QTc interval. Minor/Significance Unknown.citalopramSerious - Use Alternative (1)citalopram and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug. Coadministration may increase the risk of QT prolongation and cardiac arrhythmia.clarithromycinSerious - Use Alternative (2)clarithromycin will increase the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Decrease dose to 17 mg/day if pimavanserin is coadministered with strong CYP3A4 inhibitors. clarithromycin and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.clozapineSerious - Use Alternative (1)clozapine and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.cobicistatSerious - Use Alternative (1)cobicistat will increase the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Decrease dose to 17 mg/day if pimavanserin is coadministered with strong CYP3A4 inhibitors.conivaptanSerious - Use Alternative (1)conivaptan will increase the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Decrease dose to 17 mg/day if pimavanserin is coadministered with strong CYP3A4 inhibitors.crizotinibSerious - Use Alternative (1)crizotinib and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.cyclophosphamideMinor (1)cyclophosphamide will increase the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.dabrafenibMonitor Closely (1)dabrafenib will decrease the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration if possible. Monitor for reduced pimavanserin efficacy. An increase in pimavanserin dosage may be needed.daridorexantMonitor Closely (1)pimavanserin and daridorexant both increase sedation. Modify Therapy/Monitor Closely. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment. darunavirMonitor Closely (1)darunavir will increase the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease dose to 17 mg/day if pimavanserin is coadministered with strong CYP3A4 inhibitors.dasatinibSerious - Use Alternative (1)dasatinib and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.degarelixSerious - Use Alternative (1)degarelix and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.desfluraneSerious - Use Alternative (1)desflurane and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.deutetrabenazineMonitor Closely (3)pimavanserin and deutetrabenazine both