title: On the question of interindividual variations in chloroquine concentrations.
abstract: In a review of studies using appropriate methods for drug determinations and controlled intake, an interindividual variation in chloroquine concentrations of 2.3 to 5.6-fold was found. In our department, steady-state concentrations were evaluated in 40 patients with rheumatic diseases. The variation in whole blood concentrations was 11-fold for chloroquine and 10-fold for the desethylchloroquine metabolite. The mean ratio between desethylchloroquine and chloroquine concentrations was 0.53 and the Spearman-Rank correlation 0.92. The correlation between age and the ratio of chloroquine concentration/dose was 0.36 (P < 0.05) and the corresponding correlation for body weight was -0.43 (P < 0.05). Our data indicate that body weight and age are important independent factors for the disposition of chloroquine. However, when extensive 100-fold variations in concentrations are found between individuals we suggest that the reliability of the dose intake should be questioned.
authors.affiliation: Department of Clinical Pharmacology, Karolinska Institute, Huddinge Hospital, Sweden.
authors.forename: U
authors.initials: U
authors.lastname: Hellgren
authors.forename: G
authors.initials: G
authors.lastname: Alván
authors.forename: M
authors.initials: M
authors.lastname: Jerling
mesh_terms: D000328:Adult; D002648:Child; D002738:Chloroquine / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000097:blood* / Q000627:therapeutic use; D016903:Drug Monitoring; D006801:Humans; D008288:Malaria / Q000097:blood / Q000188:drug therapy / Q000517:prevention & control; D012216:Rheumatic Diseases / Q000097:blood / Q000188:drug therapy
chemical_list: D002738:Chloroquine; C007278:desethylchloroquine