title: Population pharmacokinetic and pharmacodynamic modeling of amodiaquine and desethylamodiaquine in women with Plasmodium vivax malaria during and after pregnancy.
abstract: Amodiaquine is effective for the treatment of Plasmodium vivax malaria, but there is little information on the pharmacokinetic and pharmacodynamic properties of amodiaquine in pregnant women with malaria. This study evaluated the population pharmacokinetic and pharmacodynamic properties of amodiaquine and its biologically active metabolite, desethylamodiaquine, in pregnant women with P. vivax infection and again after delivery. Twenty-seven pregnant women infected with P. vivax malaria on the Thai-Myanmar border were treated with amodiaquine monotherapy (10 mg/kg/day) once daily for 3 days. Nineteen women, with and without P. vivax infections, returned to receive the same amodiaquine dose postpartum. Nonlinear mixed-effects modeling was used to evaluate the population pharmacokinetic and pharmacodynamic properties of amodiaquine and desethylamodiaquine. Amodiaquine plasma concentrations were described accurately by lagged first-order absorption with a two-compartment disposition model followed by a three-compartment disposition of desethylamodiaquine under the assumption of complete in vivo conversion. Body weight was implemented as an allometric function on all clearance and volume parameters. Amodiaquine clearance decreased linearly with age, and absorption lag time was reduced in pregnant patients. Recurrent malaria infections in pregnant women were modeled with a time-to-event model consisting of a constant-hazard function with an inhibitory effect of desethylamodiaquine. Amodiaquine treatment reduced the risk of recurrent infections from 22.2% to 7.4% at day 35. In conclusion, pregnancy did not have a clinically relevant impact on the pharmacokinetic properties of amodiaquine or desethylamodiaquine. No dose adjustments are required in pregnancy.
authors.affiliation: Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand. joel@tropmedres.ac
authors.forename: Joel
authors.initials: J
authors.lastname: Tarning
authors.forename: Palang
authors.initials: P
authors.lastname: Chotsiri
authors.forename: Vincent
authors.initials: V
authors.lastname: Jullien
authors.forename: Marcus J
authors.initials: MJ
authors.lastname: Rijken
authors.forename: Martin
authors.initials: M
authors.lastname: Bergstrand
authors.forename: Mireille
authors.initials: M
authors.lastname: Cammas
authors.forename: Rose
authors.initials: R
authors.lastname: McGready
authors.forename: Pratap
authors.initials: P
authors.lastname: Singhasivanon
authors.forename: Nicholas P J
authors.initials: NP
authors.lastname: Day
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: White
authors.forename: Francois
authors.initials: F
authors.lastname: Nosten
authors.forename: Niklas
authors.initials: N
authors.lastname: Lindegardh
mesh_terms: D000293:Adolescent; D000328:Adult; D000655:Amodiaquine / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology; D000962:Antimalarials / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology; D001711:Biotransformation; D001835:Body Weight; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D016780:Malaria, Vivax / Q000097:blood / Q000188:drug therapy* / Q000469:parasitology; D017711:Nonlinear Dynamics; D010966:Plasmodium vivax / Q000187:drug effects* / Q000254:growth & development; D011247:Pregnancy; D015597:Pregnancy Complications, Parasitic / Q000097:blood / Q000188:drug therapy* / Q000469:parasitology; D055502:Secondary Prevention
chemical_list: D000962:Antimalarials; D000655:Amodiaquine; C047386:desethylamodiaquine