Pyrimethamine is a human prescription drug labeled by 'Aurobindo Pharma Limited'. National Drug Code (NDC) number for Pyrimethamine is 59651-590. This drug is available in dosage form of Tablet. The names of the active, medicinal ingredients in Pyrimethamine drug includes Pyrimethamine - 25 mg/1 . The currest status of Pyrimethamine drug is Active.

Pyrimethamine pyrimethamine pyrimethamine pyrimethamine silicon dioxide lactose monohydrate magnesium stearate starch, corn white to off-white biconvex l;25

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.

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.

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. 4 pyrimethamine has been reported to produce a significant increase in the number of lung tumors in mice when given intraperitoneally at doses of 25 mg/kg. 5 pyrimethamine should be kept out of the reach of infants and children as they are extremely susceptible to adverse effects from an ove Read more...

General: a small “starting” dose for toxoplasmosis is recommended in patients with convulsive disorders to avoid the potential nervous system toxicity of pyrimethamine. pyrimethamine should be used with caution in patients with impaired renal or hepatic function or in patients with possible folate deficiency, such as individuals with malabsorption syndrome, alcoholism, or pregnancy, and those receiving therapy, such as phenytoin, affecting folate levels (see pregnancy subsection).

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. the dosage may then be reduced to about one half that previously given for each drug and continued for an additional 4 to 5 weeks. the pediatric dosage of pyrimethamine tablets is 1 mg/kg/day divided into 2 equal daily doses; after 2 to 4 days this dose may be reduce Read more...

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.

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. doses used in toxoplasmosis may produce megaloblastic anemia, leukopenia, thrombocytopenia, pancytopenia, neutropenia, atrophic glossitis, hematuria, and disorders of cardiac rhythm. hematologic effects, however, may also occur at low doses in certain individuals (see precautions ; general ). pulmonary eosinophilia has been reported rarely.

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.

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.

Pediatric use: see dosage and administration section.

Geriatric use: clinical studies of pyrimethamine did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. other reported clinical experience has not identified differences in responses between the elderly and younger patients. in general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.

Overdosage following the ingestion of 300 mg or more of pyrimethamine, gastrointestinal and/or central nervous system signs may be present, including convulsions. the initial symptoms are usually gastrointestinal and may include abdominal pain, nausea, severe and repeated vomiting, possibly including hematemesis. central nervous system toxicity may be manifest by initial excitability, generalized and prolonged convulsions which may be followed by respiratory depression, circulatory collapse, and death within a few hours. neurological symptoms appear rapidly (30 minutes to 2 hours after drug ingestion), suggesting that in gross overdosage pyrimethamine has a direct toxic effect on the central nervous system. the fatal dose is variable, with the smallest reported fatal single dose being 375 mg. there are, however, reports of pediatric patients who have recovered after taking 375 to 625 mg. there is no specific antidote to acute pyrimethamine poisoning. in the event of overdosage, symptomatic and supportive measures should be employed. gastric lavage is recommended and is effective if carriedout very soon after drug ingestion. parenteral diazepam may be used to control convulsions. folinic acid should be administered within 2 hours of drug ingestion to be most effective in counteracting the effects on the hematopoietic system (see warnings). due to the long half-life of pyrimethamine, daily monitoring of peripheral blood counts is recommended for up to several weeks after the overdose until normal hematologic values are restored.

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

Clinical pharmacology pyrimethamine is well absorbed with peak levels occurring between 2 to 6 hours following administration. it is eliminated slowly and has a plasma half-life of approximately 96 hours. pyrimethamine is 87% bound to human plasma proteins. microbiology: pyrimethamine is a folic acid antagonist and the rationale for its therapeutic action is based on the differential requirement between host and parasite for nucleic acid precursors involved in growth. this activity is highly selective against toxoplasma gondii. the action of pyrimethamine against toxoplasma gondii is greatly enhanced when used in conjunction with sulfonamides. this was demonstrated by eyles and coleman 1 in the treatment of experimental toxoplasmosis in the mouse. jacobs et al 2 demonstrated that combination of the 2 drugs effectively prevented the development of severe uveitis in most rabbits following the inoculation of the anterior chamber of the eye with toxoplasma.

Carcinogenesis, mutagenesis, impairment of fertility: see warnings section for information on carcinogenesis.

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. they are supplied as follows: bottles of 30 ndc 59651-590-30 bottles of 100 ndc 59651-590-01 store at 20° to 25°c (68° to 77°f); excursions permitted to 15° to 30°c (59° to 86°f) [see usp controlled room temperature] in a dry place and protect from light.

Information for patients: patients should be warned that at the first appearance of a skin rash they should stop use of pyrimethamine and seek medical attention immediately. patients should also be warned that the appearance of sore throat, pallor, purpura, or glossitis may be early indications of serious disorders which require treatment with pyrimethamine to be stopped and medical treatment to be sought. women of childbearing potential who are taking pyrimethamine should be warned against becoming pregnant. patients should be warned to keep pyrimethamine out of the reach of children. patients should be advised not to exceed recommended doses. patients should be warned that if anorexia and vomiting occur, they may be minimized by taking the drug with meals. concurrent administration of folinic acid is strongly recommended when used for the treatment of toxoplasmosis in all patients.

Package label.principal display panel - 25 mg (30 tablets bottle) ndc 59651-590-30 rx only pyrimethamine tablets, usp 25 mg warning: potent drug - do not exceed recommended dosage. aurobindo 30 tablets fig