Reviewed on 6/6/2022

What Is Pimavanserin and How Does It Work?

Pimavanserin is a prescription medication used for treating hallucinations and delusions associated with Parkinson's disease psychosis

  • Pimavanserin is available under the following different brand names: Nuplazid

What Are Dosages of Pimavanserin?

Adult dosage


  • 34mg


  • 10mg

Parkinson Disease Psychosis

Adult dosage

  • 34 mg orally once a day (without titration)

Dosage Considerations – Should be Given as Follows: 

  • See “Dosages”

What Are Side Effects Associated with Using Pimavanserin?

Common side effects of Pimavanserin include:

  • nausea
  • constipation
  • swelling of the extremities
  • walking abnormally (gait disturbance)
  • hallucinations
  • confusion

Serious side effects of Pimavanserin include:

  • rash
  • hives
  • swelling of the tongue
  • throat tightness
  • shortness of breath

Rare side effects of Pimavanserin include:

  • none 

This is not a complete list of side effects and other serious side effects or health problems that may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.


Parkinson's disease is only seen in people of advanced age. See Answer

What Other Drugs Interact with Pimavanserin?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

  • Pimavanserin has severe interactions with the following drugs:
    • lefamulin
  • Pimavanserin has serious interactions with at least 99 other drugs.
  • Pimavanserin has moderate interactions with at least 91 other drugs.
  • Pimavanserin has minor interactions with the following drugs:

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all your products. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice, or if you have health questions or concerns.

What Are Warnings and Precautions for Pimavanserin?


  • Documented hypersensitivity reaction to drug or components; rash, urticaria, and reactions consistent with angioedema (e.g., tongue swelling, circumoral edema, throat tightness, and dyspnea)

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Upadacitinib?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Upadacitinib?”


  • Antipsychotic drugs increase the all-cause risk of death in elderly patients with dementia-related psychosis (see Black Box Warnings)
  • Pimavanserin is a substrate of CYP3A4; strong CYP3A4 inhibitors or inducers affect systemic exposure (see Dosage Modifications and Interactions)
  • QT prolongation

Pregnancy and Lactation

  • There are no data for use in pregnant women that would allow assessment of the drug-associated risk of major congenital malformations or miscarriage
  • In animal reproduction studies, no adverse developmental effects were seen when pimavanserin was administered orally to rats or rabbits during the period of organogenesis at doses up to 10 or 12 times the maximum recommended human dose (MRHD) of 34 mg/day, respectively
  • Lactation
    • Unknown if distributed in human breast milk
    • Consider the developmental and health benefits of breastfeeding along with the mother’s clinical need for the drug, and any potential adverse effects on the breastfed infant from the drug or the underlying maternal condition

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