CHLOROQUINE BLOOD-CONCENTRATIONS AND MALARIA PROPHYLAXIS IN TANZANIANWOMEN DURING THE 2ND-TRIMESTER AND 3RD-TRIMESTER OF PREGNANCY

Objective: Routine malaria prophylaxis with chloroquine (CQ) is recomm ended to pregnant semi-immune women in several countries in Africa. Th e dosage is empirically based. We investigated whether blood CQ concen trations and apparent oral blood clearance (CL/F) change during the co urse of pregnancy. We also studied whether malaria parasites could be detected together with low CQ blood levels. Methods: Forty nine semi-i mmune Tanzanian women were recruited in the 16th week of pregnancy. Th ey were given 310 mg oral CQ base once per week as prophylaxis during the whole pregnancy. Capillary blood samples were taken for analysis o f CQ before treatment and at weeks 26 and 36. Blood samples were dried on filter paper and analysed by HPLC. Blood was also drawn to detect occurrence of malaria parasites. Results: A total of 25 women fulfille d the sampling schedule. CL/F increased significantly from 160 ml.min( -1) at week 26 to 180 ml.min(-1) at week 36. In 7 of 25 women, CL/F in creased >20%. Trough blood CQ concentrations, determined on four occas ions at week 26 and at week 36 varied between 200 and 900 nmol.l(-1) N o statistically significant differences between occasions were seen. M alaria parasites were seen in two individuals early in pregnancy. Conc lusion: Blood CQ CL/F showed a small increase during the course of pre gnancy. The estimated mean blood CL/F values of 160 and 180 ml.min(-1) (week 26 and 36, respectively) were higher than the mean CL/F of 125 ml.min(-1) in non-pregnant individuals, published previously. Efficacy of higher dosages of CQ in malaria prophylaxis in pregnant women coul d, therefore, be evaluated in controlled trials in high-risk malaria a reas.