Applies to pyrimethamine: oral tablet
Along with its needed effects, pyrimethamine 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:
Frequency not known
Symptoms of overdose
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:
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.
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
Precipitation of a grand mal attack in a patient predisposed to epilepsy was reported; clinical significance was not established.
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
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
Very common (10% or more): Rash
Uncommon (0.1% to 1%): Abnormal skin pigmentation, dermatitis
Uncommon (0.1% to 1%): Fever, malaise
Insomnia was reported when this drug was given weekly at higher than recommended doses.
Uncommon (0.1% to 1%): Depression
Very rare (less than 0.01%): Insomnia
Rare (0.01% to 0.1%): Pulmonary eosinophilia
Very rare (less than 0.01%): Pneumonia with cellular and eosinophilic pulmonary infiltration
Pneumonia with cellular and eosinophilic pulmonary infiltration was observed when this drug was administered once a week with sulfadoxine.
Frequency not reported: Hypersensitivity reactions (included erythema multiforme, Stevens-Johnson Syndrome, toxic epidermal necrolysis, Lyell's syndrome, hepatitis, anaphylaxis, pulmonary reactions, maculopapular rashes)
Circulatory collapse was reported in patients treated with higher than recommended doses.
Very rare (less than 0.01%): Circulatory collapse
Frequency not reported: Disorders of cardiac rhythm, arrhythmias
Hyperphenylalaninemia was reported in neonates treated for congenital toxoplasmosis.
Very rare (less than 0.01%): Hyperphenylalaninemia
Frequency not reported: Anorexia
Very rare (less than 0.01%): Hematuria
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.
Frequency not reported: Chronic granulocytic leukemia, reticulum cell sarcoma
Medically reviewed by BestRx Medical Team Last updated on 1/1/2020.
Source: Drugs.com Pyrimethamine