Epidemiology of chloroquine-induced pruritus and its influence on chloroquine utilization in a coastal district of Kenya

Abstract

A cohort study of 547 outpatients with a diagnosis

6f clinical malaria was conducted in two health centres ~ in Mombasa DisJrict between October 1986 and March 1987. h

There were 307 males and 240 females of ages ranging from

, to 75 years. The study group of 277 patients was put on chloroquine and a comparative ~roup of 270 patients was put on aspirin. The patients were reviewed after 2¢ hours and asked about itching.

Of all the patients, 93 out of 547 (17%) developed itching. In the study group 62 out of 277 patients treated with chloroquine (22.38%) developed itching and in the comparative group 31 out of 270 treated with aspirin (11.48%) developed itching. giving a significant difference with a relative risk of 2~2 (95~ confidence limits 1.38 to 3.53). The general features of itching were similar for both study and comparative groups. The mean interval from ingestion of chloroquine to onset of itching was 8 hours and it affected mainly the hands and the feet. Nearly half the patients found the itching severe enough to interfere with their sleep.

The significant determinants of itching were: blood slide positivity for malaria parasites; previous history of itching with chloroquine Qr any other drug and frequent attacks of malaria especially if chloroquine was used during these attacks •.

Chloroquine was found to be the most commonly used I

ant1.ma

1a,61r• 1a 1 drug, both for chemotherapy and

chemoprophylaxis. There was no significant difference in the antimalarial drug used for chemotherapy between patients with previous history of itching due to chloroquine and those.with no history of itching due to chlo~oquine. There w~s however, a ~ignificant difference in anitmalarial drugs useJ for chemoprophylaxis in patients with previous history of itching with chloroquine and those with no such history. The future acceptability of chloroquine though high (95.3%) was significantly lower

than that of aspirin.

This study shows that chloroquine-induced itching is an important problem and should be considered in all places where the drug is used extensively.