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Daraprim Side Effects

Generic name: pyrimethamine

Medically reviewed by Last updated on Jan 19, 2024.

Note: This document contains side effect information about pyrimethamine. Some dosage forms listed on this page may not apply to the brand name Daraprim.

Applies to pyrimethamine: oral tablet.

Serious side effects of Daraprim

Along with its needed effects, pyrimethamine (the active ingredient contained in Daraprim) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking pyrimethamine:


Incidence not known

Other side effects of Daraprim

Some side effects of pyrimethamine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Incidence not known

For Healthcare Professionals

Applies to pyrimethamine: compounding powder, oral tablet.


Since this drug is coadministered with a sulfonamide, the manufacturer product information for the relevant sulfonamide should be consulted for sulfonamide-related side effects.[Ref]


Very common (10% or more): Nausea, vomiting, diarrhea, colic

Uncommon (0.1% to 1%): Dry mouth, dry throat

Very rare (less than 0.01%): Buccal ulceration

Frequency not reported: Glossitis, atrophic glossitis[Ref]

Nervous system

Very common (10% or more): Headache

Common (1% to 10%): Dizziness

Very rare (less than 0.01%): Convulsions/seizures

Frequency not reported: Ataxia, tremors, precipitation of grand mal attack[Ref]

Precipitation of a grand mal attack in a patient predisposed to epilepsy was reported; clinical significance was not established.[Ref]


Very common (10% or more): Anemia

Common (1% to 10%): Thrombocytopenia, leukopenia

Very rare (less than 0.01%): Pancytopenia

Frequency not reported: Megaloblastic anemia, neutropenia, agranulocytosis[Ref]


Very common (10% or more): Rash

Uncommon (0.1% to 1%): Abnormal skin pigmentation, dermatitis


Uncommon (0.1% to 1%): Fever, malaise


Uncommon (0.1% to 1%): Depression

Very rare (less than 0.01%): Insomnia

Insomnia was reported when this drug was given weekly at higher than recommended doses.


Rare (0.01% to 0.1%): Pulmonary eosinophilia

Very rare (less than 0.01%): Pneumonia with cellular and eosinophilic pulmonary infiltration[Ref]

Pneumonia with cellular and eosinophilic pulmonary infiltration was observed when this drug was administered once a week with sulfadoxine.[Ref]


Frequency not reported: Hypersensitivity reactions (included erythema multiforme, Stevens-Johnson Syndrome, toxic epidermal necrolysis, Lyell's syndrome, hepatitis, anaphylaxis, pulmonary reactions, maculopapular rashes)[Ref]


Very rare (less than 0.01%): Circulatory collapse

Frequency not reported: Disorders of cardiac rhythm, arrhythmias[Ref]

Circulatory collapse was reported in patients treated with higher than recommended doses.[Ref]


Very rare (less than 0.01%): Hyperphenylalaninemia

Frequency not reported: Anorexia[Ref]

Hyperphenylalaninemia was reported in neonates treated for congenital toxoplasmosis.[Ref]


Very rare (less than 0.01%): Hematuria


Frequency not reported: Chronic granulocytic leukemia, reticulum cell sarcoma[Ref]

A 51-year-old female developed chronic granulocytic leukemia after taking this drug for 2 years for toxoplasmosis and a 56-year-old patient developed reticulum cell sarcoma after taking this drug for 14 months for toxoplasmosis.[Ref]


1. Cerner Multum, Inc. UK Summary of Product Characteristics.

2. Cerner Multum, Inc. Australian Product Information.

3. Product Information. Daraprim (pyrimethamine). Glaxo Wellcome. 2001;PROD.

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.