Pyrimethamine
Generic Name: pyrimethamine
Brand Names:
Pyrimethamine
DESCRIPTION Pyrimethamine is an antiparasitic compound available in tablet form for oral administration. Each scored tablet contains 25 mg pyrimethamine USP and the inactive ingredients colloidal silicon dioxide, lactose monohydrate, magnesium stearate and pregelatinized starch (corn). Pyrimethamine USP, known chemically as 5-(4- chlorophenyl)-6-ethyl-2, 4-pyrimidinediamine, has the following structural formula: str
Overview
DESCRIPTION Pyrimethamine is an antiparasitic compound available in tablet form for oral administration. Each scored tablet contains 25 mg pyrimethamine USP and the inactive ingredients colloidal silicon dioxide, lactose monohydrate, magnesium stearate and pregelatinized starch (corn). Pyrimethamine USP, known chemically as 5-(4- chlorophenyl)-6-ethyl-2, 4-pyrimidinediamine, has the following structural formula: str
Uses
INDICATIONS AND USAGE Treatment of Toxoplasmosis: Pyrimethamine tablets are indicated for the treatment of toxoplasmosis when used conjointly with a sulfonamide, since synergism exists with this combination.
Dosage
DOSAGE AND ADMINISTRATION For Treatment of Toxoplasmosis: The dosage of pyrimethamine tablets for the treatment of toxoplasmosis must be carefully adjusted so as to provide maximum therapeutic effect and a minimum of side effects. At the dosage required, there is a marked variation in the tolerance to the drug. Young patients may tolerate higher doses than older individuals. Concurrent administration of folinic acid is strongly recommended in all patients. The adult starting dose is 50 to 75 mg of the drug daily, together with 1 to 4 g daily of a sulfonamide of the sulfapyrimidine type, e.g. sulfadoxine. This dosage is ordinarily continued for 1 to 3 weeks, depending on the response of the patient and tolerance to therapy.
Side Effects
ADVERSE REACTIONS Hypersensitivity reactions, occasionally severe (such as Stevens-Johnson syndrome, toxic epidermal necrolysis, erythema multiforme, and anaphylaxis), and hyperphenylalaninemia, can occur particularly when pyrimethamine is administered concomitantly with a sulfonamide. Consult the complete prescribing information for the relevant sulfonamide for sulfonamide-associated adverse events. With doses of pyrimethamine used for the treatment of toxoplasmosis, anorexia and vomiting may occur. Vomiting may be minimized by giving the medication with meals; it usually disappears promptly upon reduction of dosage.
Interactions
Drug Interactions: Pyrimethamine may be used with sulfonamides, quinine and other antimalarials, and with other antibiotics. However, the concomitant use of other antifolic drugs or agents associated with myelosuppression including sulfonamides or trimethoprim-sulfamethoxazole combinations, proguanil, zidovudine, or cytostatic agents (e.g., methotrexate), while the patient is receiving pyrimethamine, may increase the risk of bone marrow suppression. If signs of folate deficiency develop, pyrimethamine should be discontinued. Folinic acid (leucovorin) should be administered until normal hematopoiesis is restored (see WARNINGS ). Mild hepatotoxicity has been reported in some patients when lorazepam and pyrimethamine were administered concomitantly.
Warnings
WARNINGS The dosage of pyrimethamine required for the treatment of toxoplasmosis has a narrow therapeutic window. If signs of folate deficiency develop (see ADVERSE REACTIONS ), reduce the dosage or discontinue the drug according to the response of the patient. Folinic acid (leucovorin) should be administered in a dosage of 5 to 15 mg daily (orally, IV, or IM) until normal hematopoiesis is restored. Data in 2 humans indicate that pyrimethamine may be carcinogenic; a 51-year-old female who developed chronic granulocytic leukemia after taking pyrimethamine for 2 years for toxoplasmosis 3 and a 56-year-old patient who developed reticulum cell sarcoma after 14 months of pyrimethamine for toxoplasmosis. CONTRAINDICATIONS Use of pyrimethamine tablets are contraindicated in patients with known hypersensitivity to pyrimethamine or to any component of the formulation. Use of the drug is also contraindicated in patients with documented megaloblastic anemia due to folate deficiency.
Pregnancy
Mutagenesis: Pyrimethamine has been shown to be nonmutagenic in the following in vitro assays: the Ames point mutation assay, the Rec assay, and the E. coli WP2 assay. It was positive in the L5178Y/TK +/- mouse lymphoma assay in the absence of exogenous metabolic activation. 6 Human blood lymphocytes cultured in vitro had structural chromosome aberrations induced by pyrimethamine. In vivo, chromosomes analyzed from the bone marrow of rats dosed with pyrimethamine showed an increased number of structural and numerical aberrations.
Storage
HOW SUPPLIED: Pyrimethamine Tablets USP, 25 mg are white to off-white round shaped, biconvex, uncoated tablet, debossed with ‘L’ ‘25’ on one side and break line on other side.
Frequently Asked Questions
What is Pyrimethamine used for?▼
INDICATIONS AND USAGE Treatment of Toxoplasmosis: Pyrimethamine tablets are indicated for the treatment of toxoplasmosis when used conjointly with a sulfonamide, since synergism exists with this combination.
What are the side effects of Pyrimethamine?▼
ADVERSE REACTIONS Hypersensitivity reactions, occasionally severe (such as Stevens-Johnson syndrome, toxic epidermal necrolysis, erythema multiforme, and anaphylaxis), and hyperphenylalaninemia, can occur particularly when pyrimethamine is administered concomitantly with a sulfonamide. Consult the complete prescribing information for the relevant sulfonamide for sulfonamide-associated adverse events. With doses of pyrimethamine used for the treatment of toxoplasmosis, anorexia and vomiting may occur. Vomiting may be minimized by giving the medication with meals; it usually disappears promptly upon reduction of dosage.
Can I take Pyrimethamine during pregnancy?▼
Mutagenesis: Pyrimethamine has been shown to be nonmutagenic in the following in vitro assays: the Ames point mutation assay, the Rec assay, and the E. coli WP2 assay. It was positive in the L5178Y/TK +/- mouse lymphoma assay in the absence of exogenous metabolic activation. 6 Human blood lymphocytes cultured in vitro had structural chromosome aberrations induced by pyrimethamine. In vivo, chromosomes analyzed from the bone marrow of rats dosed with pyrimethamine showed an increased number of structural and numerical aberrations.
What are the important warnings for Pyrimethamine?▼
WARNINGS The dosage of pyrimethamine required for the treatment of toxoplasmosis has a narrow therapeutic window. If signs of folate deficiency develop (see ADVERSE REACTIONS ), reduce the dosage or discontinue the drug according to the response of the patient. Folinic acid (leucovorin) should be administered in a dosage of 5 to 15 mg daily (orally, IV, or IM) until normal hematopoiesis is restored. Data in 2 humans indicate that pyrimethamine may be carcinogenic; a 51-year-old female who developed chronic granulocytic leukemia after taking pyrimethamine for 2 years for toxoplasmosis 3 and a 56-year-old patient who developed reticulum cell sarcoma after 14 months of pyrimethamine for toxoplasmosis. CONTRAINDICATIONS Use of pyrimethamine tablets are contraindicated in patients with known hypersensitivity to pyrimethamine or to any component of the formulation. Use of the drug is also contraindicated in patients with documented megaloblastic anemia due to folate deficiency.
Related Medications
Zanidatamab-hrii
zanidatamab-hrii
Bispecific HER2-directed Antibody [EPC]
11 DESCRIPTION Zanidatamab‑hrii is a humanized, IgG-like, bispecific HER2-directed antibody. Zanidatamab‑hrii is produced in Chinese hamster ovary cells via recombinant DNA technology and has a molecular weight of 124.8 kDa. ZIIHERA (zanidatamab‑hrii) for injection is supplied as a sterile, preservative free, white lyophilized powder that requires reconstitution and dilution for intravenous use.
Centropristis Striata
centropristis striata
Dosage form: SOLUTION. Route: INTRADERMAL, PERCUTANEOUS, SUBCUTANEOUS. Active ingredients: BLACK SEA BASS (.05 g/mL). Category: BLA.
Baptisia Tinctoria, Echinacea Purp, Glycyrrhiza Glabra, Astragalus, Candida Alb, Borax, Calc Carb, Kreosotum, Lycopodium, Nux Vom, Phosphoricum Ac, Pulsatilla, Sepia, Thuja Occ, Nat Phos, Nitricum Ac
baptisia tinctoria, echinacea purp, glycyrrhiza glabra, astragalus, candida alb, borax, calc carb, kreosotum, lycopodium, nux vom, phosphoricum ac, pulsatilla, sepia, thuja occ, nat phos, nitricum ac
Non-Standardized Fungal Allergenic Extract [EPC]
USES: Temporarily relieves symptoms associated with vaginal yeast.**
Medical Disclaimer
This drug information is for educational purposes only and should not replace professional medical advice. Drug information is sourced from the FDA National Drug Code Directory and Structured Product Labeling. Always consult with a healthcare provider before starting, stopping, or changing any medication.