Population pharmacokinetics of orally administered mefloquine in healthy volunteers and patients with uncomplicated Plasmodium falciparum malaria.
BACKGROUND
The determination of dosing regimens for the treatment of malaria is largely empirical and thus a better understanding of the pharmacokinetic/pharmacodynamic properties of antimalarial agents is required to assess the adequacy of current treatment regimens and identify sources of suboptimal dosing that could select for drug-resistant parasites. Mefloquine is a widely used antimalarial, commonly given in combination with artesunate.


METHODS
Mefloquine pharmacokinetics was assessed in 24 healthy adults and 43 patients with Plasmodium falciparum malaria administered mefloquine in combination with artesunate. Population pharmacokinetic modelling was conducted using NONMEM.


RESULTS
A two-compartment model with a single transit compartment and first-order elimination from the central compartment most adequately described mefloquine concentration-time data. The model incorporated population parameter variability for clearance (CL/F), central volume of distribution (VC/F) and absorption rate constant (KA) and identified, in addition to body weight, malaria infection as a covariate for VC/F (but not CL/F). Monte Carlo simulations predict that falciparum malaria infection is associated with a shorter elimination half-life (407 versus 566 h) and T>MIC (766 versus 893 h).


CONCLUSIONS
This is the first known population pharmacokinetic study to show falciparum malaria to influence mefloquine disposition. Protein binding, anaemia and other factors may contribute to differences between healthy individuals and patients. As VC/F is related to the earlier portion of the concentration-time profiles, which occurs during acute malaria, and CL/F is more related to the terminal phase during convalescence after treatment, this may explain why malaria was found to be a covariate for VC/F but not CL/F.
School of Pharmacy & Medical Sciences, University of South Australia, Adelaide, SA, Australia Sansom Institute for Health Research, University of South Australia, Adelaide, SA, Australia.
Stephanie E
SE
Reuter
School of Pharmacy & Medical Sciences, University of South Australia, Adelaide, SA, Australia Sansom Institute for Health Research, University of South Australia, Adelaide, SA, Australia.
Richard N
RN
Upton
School of Pharmacy & Medical Sciences, University of South Australia, Adelaide, SA, Australia Sansom Institute for Health Research, University of South Australia, Adelaide, SA, Australia.
Allan M
AM
Evans
Centre for Drug Research, Universiti Sains Malaysia, Penang, Malaysia Postgraduate, Research and Strategic Development, Taylor's University, Selangor, Malaysia.
Visweswaran
V
Navaratnam
UNICEF/UNDP/World Bank/WHO Special Programme for Research & Training in Tropical Diseases (TDR), Geneva, Switzerland Centre for Tropical Medicine and Vaccinology, Nuffield Department of Medicine, University of Oxford, Churchill Hospital, Oxford, UK olliarop@who.int.
Piero L
PL
Olliaro
D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000962:Antimalarials / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D037621:Artemisinins / Q000008:administration & dosage; D000077332:Artesunate; D018592:Cross-Over Studies; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D016778:Malaria, Falciparum / Q000188:drug therapy*; D008297:Male; D015767:Mefloquine / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D008875:Middle Aged; D009010:Monte Carlo Method; D010949:Plasma / Q000737:chemistry; D055815:Young Adult
D000962:Antimalarials; D037621:Artemisinins; D000077332:Artesunate; D015767:Mefloquine
P. falciparum; PK; pharmacometrics