Antimalarial prophylaxis--use and adverse events in visitors to the Kruger National Park

Abstract

Objectives: To determine the use of antimalarial prophylaxis and the relative frequency of adverse events with different regimens in visitors to the Kruger National Park.

Design: Retrospective postal survey of a cohort of 7,397 visitors during April 1996. Telephonic interviews were conducted with all respondents who reported neuropsychiatric adverse events necessitating medical attention, and their medical caregivers.

Results: The most commonly used regimens were chloroquine and proguanil in combination (C&P) (35.6%) and mefloquine (18.4%). However, non-recommended regimens were also used by travellers to this chloroquine-resistant area, including chloroquine alone (15.7%). Adverse events were reported by 23.8% of travellers and were more common in the C&P group than the mefloquine group (28.9% v. 25.0%, P = 0.0100). Gastro-intestinal side-effects were significantly more common in the C&P group (nausea (P = 0.0170), diarrhoea (P = 0.0008), mouth ulcers (P = 0.0000)), while neuropsychiatric side-effects were more common in the mefloquine group (depression (P = 0.0000), light-headedness (P = 0.0009), anxiety (P = 0.0060)). Only 30% of travellers reported using antimalarial drugs both regularly as prescribed and for 4 weeks after leaving the malaria area. The most commonly reported reason for changing prophylaxis was advice from a physician or pharmacist (41.9%).

Conclusions: Health professionals providing medical advice to prospective travellers to malarious areas must tailor recommendations based on the balance between malaria risk in a specific geographical area and the benefits and tolerance of protective measures. Mosquito-avoidance measures should always be advocated, but counselling on antimalarial prophylaxis will be guided by the malaria/prophylaxis (serious adverse events) risk ratio. Where drug measures are indicated, the importance of their correct use should be emphasised.