Use and misuse of 4-aminoquinoline antimalarials in tropical Africa and re-examination of itch reaction to these drugs.

Abstract

A total of 1059 persons from 14 different locations in Ibadan (the most populous city in tropical Africa) were interviewed to determine whether they had had itch reaction with each of the 12 4-aminoquinoline preparations (one amodiaquine hydrochloride, 11 chloroquine). The various trade and pharmacological names are listed in a table. Respondents were asked for what purpose the listed drugs were used: treatment of an attack of malaria fever; prevention of malaria; and other conditions or illnesses. The respondents were also asked how often each subject had an attack of malaria: monthly, every 3 months, every 6 months, once a year, once every 2-3 years, less often than this, never. Inquiry was made regarding details of the itch reaction since there was particular interest in the pruritus which, judging from previous studies, constitutes the 1 reaction most likely to make 4-aminoquinolines unpopular. Chloroquine sulphate tablets, the 8th most popular preparation, was the 6th on the list of itching incidence. There appeared to be no difference in the incidence of itching after chloroquine sulphate injection. Avloclor tablets, chloroquine phosphate injection tablets and Malarex and Aralen tablets gave a comparatively low incidence of itch reaction--3.4% and 1.4% respectively within the population studied. The incidence of itching after these 4-aminoquinoline preparations may also be estimated in the population sampled by finding the mean percentage of the subjects who itch within those who admitted taking each preparation mentioned in the questionnaire. The corrected percentage incidence gave an estimated mean of 28% compared with a mean incidence of 11% when projected to the whole population sampled. Most of the people (90%) used the 4-aminoquinoline antimalarials to treat an attack of malaria fever; 23% take them for prophylaxis and 7% in the population used the drugs for nonmalarial ailments. The misuse of the drugs for nonmalarial ailments may be related to their potency in treating malaria. In sum, the itch reaction failed to conform to a simple clinical pattern.