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Pyrimethamine use while Breastfeeding

Drugs containing Pyrimethamine: Daraprim, Fansidar

Pyrimethamine Levels and Effects while Breastfeeding

Summary of Use during Lactation

No adverse reactions in breastfed infants have been reported and it is acceptable in nursing mothers. In HIV-infected women, elevated viral HIV loads in milk were decreased after treatment with chloroquine to a greater extent than other women who were treated with the combination of sulfadoxine and pyrimethamine.[1]

Drug Levels

Maternal Levels. Pyrimethamine milk levels have been reported after doses of 25, 50 or 75 mg in 16 women. Milk levels ranged from 2.7 to 3.3 mg/L at 6 hours after the dose, 1.6 to 2 mg/L at 24 hours after the dose, and 0.66 to 1 mg/L at 48 hours after the dose (3 women only). Reported milk levels were not proportional to the dose in this old study using an antiquated assay method.[2][3]

Three women were given a single dose of pyrimethamine 12.5 mg orally 2 to 5 days postpartum. Milk samples were obtained periodically for about 9 days after the dose. Assuming a daily intake of 1 L of milk, the infants would receive 0.14, 0.21 and 0.34 mg in milk over the study period. The authors calculated that these values equated to an average of 30% (range 16.8 to 45.6%) of the maternal weight-adjusted dosage.[4]

Infant Levels. Relevant published information was not found as of the revision date.

Effects in Breastfed Infants

Administration of pyrimethamine to mothers of 26 predominantly breastfed infants 2 to 6 months old who were infected with malaria was curative in the infants.[3] The regimen consisted of 75 mg followed by a subsequent dose of 50-75 mg 4 to 7 days later. The efficacy apparently is related to breastfeeding habits, because infants in another tribal group who breastfed their infants less extensively were not protected.[2]

A case report indicates that a maternal dose of 75 mg orally followed by 25 mg weekly cured malaria in her breastfed infant and protected her infant against becoming infected with malaria for 6 months. After the mother missed taking her dose for 2 weeks, the infant developed symptoms of malaria.[5] No adverse effects were reported in any of the infants.

Effects on Lactation and Breastmilk

Relevant published information was not found as of the revision date.

References

1. Semrau K, Kuhn L, Kasonde P et al. Impact of chloroquine on viral load in breast milk. Trop Med Int Health. 2006;11:800-3. PMID: 16772000

2. Clyde DF. An examination of factors involved in the transfer of pyrimethamine in human milk. East Afr Med J. 1957;34:81-5. PMID: 13437933

3. Clyde DF, Press J, Shute GT. Transfer of pyrimethamine in human milk. J Trop Med Hyg. 1956;59:277-84. PMID: 13385913

4. Edstein MD, Veenendaal JR, Newman K et al. Excretion of chloroquine, dapsone and pyrimethamine in human milk. Br J Clin Pharmacol. 1986;22:733-5. PMID: 3567020

5. Clyde DF. Prolonged malaria prophylaxis through pyrimethamine in mothers' milk. East Afr Med J. 1960;37:659-60. PMID: 13694157

Pyrimethamine Identification

Substance Name

Pyrimethamine

CAS Registry Number

58-14-0

Drug Class

Antimalarials

Administrative Information

LactMed Record Number

302

Last Revision Date

20130907

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