Dosing and uses of Daraprim (pyrimethamine)
Adult dosage forms and strengths
tablet
- 25mg
Toxoplasmosis
50-75 mg qD PO for 1-3 weeks, THEn
25-37.5 mg qD PO for 4-5 weeks
P jiroveci Pneumonia (Off-label)
Prophylaxis p P jiroveci pneumonia (formerly Pneumocystis pneumonia); administer with dapsone
50-75 mg PO once/week
Tay-Sachs & Sandhoff Disease (Orphan)
Treatment of GM-2 gangliosidoses (Tay-Sachs disease and Sandhoff disease)
Orphan indication sponsor
- ExSAR Corporation; 11 Deer Park Drive; Monmouth Junction, NJ 08852
Other Indications & Uses
Treatment & prevention of toxoplasmosis (with sulfadiazine, clindamycin, or atovaquone); malaria
Off-label: prophylaxis of P. jiroveci pneumonia (with dapsone), isosporiasis
Pediatric dosage forms and strengths
tablet
- 25mg
>2 Months Old
Congenital Toxoplasmosis
- Loading dose: 2 mg/kg/day divided q12hr PO for 2 days
- Maintenance.: First 2-6 months old: 1 mg/kg PO qD for 2-6 months old; THEN remainder of 12 months old; 1 mg/kg PO 3 times/week
Toxoplasmosis
- Loading dose: 2 mg/kg/d divided q12hr PO for 3 days
- Maintenance: 1 mg/kg PO qD for 4 weeks
< 2 months old: Safety and efficacy not established
Daraprim (pyrimethamine) adverse (side) effects
Frequency not defined
Abdominal cramps
Abnormal skin pigmentation
Anaphylaxis
Anorexia
Arrhythmias (large doses)
Atrophic glossitis
Depression
Fever
Insomnia
Lightheadedness
Malaise
Seizures
Dermatitis
Erythema multiforme
Rash
Stevens-Johnson syndrome
Vomiting
Diarrhea
Xerostomia
Megaloblastic anemia
Leukopenia
Pancytopenia
Thrombocytopenia
Pulmonary eosinophilia
Warnings
Contraindications
Hypersensitivity
Megaloblastic or folate-deficiency anemia
Severe renal dz
Breastfeeding
Cautions
Hepatic/renal dz, anemia, myelosuppression, epilepsy
No longer recommended for malaria prevention or acute Tx if used alone
Use w/ leucovorin, esp. at high doses
Pregnancy and lactation
Pregnancy category: C
Lactation: enters breast milk, do not nurse
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Daraprim (pyrimethamine)
Onset: ~1 hr
Absorption: well absorbed
Distribution: widely, mainly in blood cells, kidneys, lungs, liver, & spleen; crosses into CSF; crosses placenta; enters breast milk
Protein Bound: 80-87%
Metabolism: hepatic
Half-life elimination: 80-95 hr
Peak Plasma Time: 1.5-8 hr
Excretion: urine (20-30% as unchanged drug)
Mechanism of action
Folic acid antagonist
