Pharmacokinetics of Drugs Used to Treat Uncomplicated Malaria in Breastfeeding Mother-infant Pairs: An Observational Pharmacokinetic Study

Lactating women requiring treatment for uncomplicated malaria will be identified and invited for sampling. The decision to treat them with first-line treatment will have been made by the clinician, not by a member of the study team. The study team will not make any adjustments to the prescribed treatment. Artemether-lumefantrine comprises six doses of medication, with the initial two doses given 8 hours apart on Day 1, and dosing 12-hourly on Day 2 and Day 3. Intensive pharmacokinetic sampling will be undertaken after Dose 5, as indicated in the schema under Section 5: plasma and breastmilk samples will be obtained pre-dose and at 2, 4, 6, 8 hours after dose. In addition, sparse sampling will be undertaken on either of these occasions; at pre-dose and between 1 to 6 hours after the first dose; a trough (pre-dose) sample after the Dose 3 or Dose 4 and lastly at 5, 7, and up to 14-days after the first dose. A heelprick sample will also be obtained from the breastfed infants at maternal trough (prior to maternal dose) and at a random timepoint (once per infant) over the 8-hour pharmacokinetic sampling visit to characterize concentrations of these drugs over an 8-hour dosing interval. In addition, a single heelprick sample will be obtained from the infant whenever the mother returns after treatment for the late sampling time points (5, 7, and 14 days post the first dose). Due to the long half-life of lumefantrine of approximately 6 days plasma sampling will be performed up to day 14 to characterise the terminal elimination of the drug. Concentrations of total plasma and breastmilk lumefantrine and desbutyl-lumefantrine will be determined.