PLASMA CHLOROQUINE CONCENTRATIONS IN YOUNG AND OLDER MALARIA PATIENTSTREATED WITH CHLOROQUINE

Plasma chloroquine (CQ) concentrations were measured by bioassay in yo ung (0-4 years, n = 9) and older (5-60 years, n = 21) patients from Va nuatu infected with malaria following treatment with 25 mg/kg CQ over 3 days. CQ concentrations in young children tended to be lower than in older patients at days 2, 3, 4 and 7 after onset of treatment, with n o drug present in two young children on day 3 and in one child on day 7. The greater difficulty experienced by young children to ingest all of their prescribed medication could have contributed to the lower CQ concentrations observed in the younger age group. The possibility that sub-therapeutic CQ concentrations are responsible for treatment failu res in young children should be considered in areas where a high degre e of CQ resistance has not yet been established. In such areas, the pr esence or prevalence of CQ-resistant infections should not be based on treatment failures observed in young children unless it can be confir med that adequate blood CQ concentrations were achieved after treatmen t. (C) 1997 Elsevier Science B.V.