Systematic (IUPAC) name
Clinical data
Legal status
Routes Oral
Pharmacokinetic data
Protein binding 94-97%[1]
Half-life 54-56 hours[1]
CAS number  YesY
706782-28-7 (tartrate)
ATC code None
ChemSpider  N
Chemical data
Formula C25H34FN3O2 
Mol. mass 427.553 g/mol

Pimavanserin (ACP-103), marketed under the trade name Nuplazid, is a drug developed by Acadia Pharmaceuticals which acts as an inverse agonist on the serotonin receptor subtype 5-HT2A, with 40x selectivity over 5-HT2C, and no significant affinity or activity at 5-HT2B or dopamine receptors.[1] As of September 3 2009, pimavanserin has not met expectations for Phase III clinical trials for the treatment of Parkinson's disease psychosis,[2] and is in Phase II trials for adjunctive treatment of schizophrenia alongside an antipsychotic medication.[3] It is expected to improve the effectiveness and side effect profile of antipsychotics.[4][5][6] The results of a clinical trial examining the efficacy, tolerability and safety of adjunctive pimavanserin to risperidone and haloperidol were published in November 2012 and the results showed that pimavanserin potentiated the antipsychotic effects of subtherapeutic doses of risperidone and improve the tolerability of haloperidol treatment by reducing the incidence of extrapyramidal symptoms.[7]

On September 2, 2014, the United States Food and Drug administration granted Breakthrough Therapy status to Acadia's New Drug Application for pimavanserin.[1]


  1. ^ a b c Friedman, JH (October 2013). "Pimavanserin for the treatment of Parkinson’s disease psychosis". Expert Opinion on Pharmacotherapy 14 (14): 1969–1975.  
  2. ^ ACADIA Pharmaceuticals. "Treating Parkinson's Disease - Clinical Trial Pimavanserin - ACADIA". Retrieved 2009-04-11. 
  3. ^ "ACADIA Announces Positive Results From ACP-103 Phase II Schizophrenia Co-Therapy Trial" (Press release). ACADIA Pharmaceuticals. 2007-03-19. Retrieved 2009-04-11. 
  4. ^ Gardell LR, Vanover KE, Pounds L, Johnson RW, Barido R, Anderson GT, Veinbergs I, Dyssegaard A, Brunmark P, Tabatabaei A, Davis RE, Brann MR, Hacksell U, Bonhaus DW (August 2007). "ACP-103, a 5-hydroxytryptamine 2A receptor inverse agonist, improves the antipsychotic efficacy and side-effect profile of haloperidol and risperidone in experimental models". J Pharmacol Exp Ther 322 (2): 862–70.  
  5. ^ Vanover KE, Betz AJ, Weber SM, Bibbiani F, Kielaite A, Weiner DM, Davis RE, Chase TN, Salamone JD (October 2008). "A 5-HT2A receptor inverse agonist, ACP-103, reduces tremor in a rat model and levodopa-induced dyskinesias in a monkey model". Pharmacol Biochem Behav 90 (4): 540–4.  
  6. ^ Abbas A, Roth BL (December 2008). "Pimavanserin tartrate: a 5-HT2A inverse agonist with potential for treating various neuropsychiatric disorders". Expert Opin Pharmacother 9 (18): 3251–9.  
  7. ^ Meltzer, HY; Elkis, H; Vanover, K; Weiner, DM; van Kammen, DP; Peters, P; Hacksell, U (November 2012). "Pimavanserin, a selective serotonin (5-HT)2A-inverse agonist, enhances the efficacy and safety of risperidone, 2mg/day, but does not enhance efficacy of haloperidol, 2mg/day: comparison with reference dose risperidone, 6mg/day". Schizophrenia Research 141 (2-3): 144–152.