Profile of adverse events in patients receiving treatment for malaria in urban Ghana: a cohort-event monitoring study.

BACKGROUND: Antimalarial treatment strategies have changed much in the last 15 years, resulting in an increased variety of medicines available. Active pharmacovigilance methods are important for continued safety surveillance of these medicines, particularly in environments in which there is variability in treatments prescribed and limited confirmatory diagnostic capacity as well as limited ability of spontaneous reporting pharmacovigilance systems to generate much needed safety information quickly and efficiently.

OBJECTIVE: Our objective was to use the cohort-event monitoring (CEM) technique to gather drug utilization and adverse event data for patients prescribed antimalarial medicines in an outpatient setting.

METHODS: The characteristics of a large urban African cohort of outpatients (n = 2,831) receiving antimalarial medications are described. The cohort was actively surveyed over the subsequent week to record adverse events, using follow-up phone calls, paper reports, and/or voluntary return clinic visits. Adverse events reported in the cohort were analysed overall and by clinically relevant age and medication groupings.

RESULTS: At least one event was reported in 29.4 % of patients. Adverse events were more likely to be reported in subjects older than 12 years of age, and by patients prescribed an artesunate-amodiaquine combination. A range of adverse events were reported, the most frequent higher level terms being asthenic conditions (10.1 % of total cohort), neurological signs and symptoms (4.5 %), headaches (3.1 %), appetite disorders (2.1 %), and disturbances in consciousness (1.6 %). There were three reports of possible extrapyramidal events (two cases of tremor "hand and back shaking all over" and one case of tongue protrusion), which may appear to be related to combinations including amodiaquine and an artemisinin.

CONCLUSION: The CEM methodology is a useful tool for monitoring the safety of widely available and utilized medicines, particularly in an urban environment where spontaneous reporting yields poor results and where the availability of various regimens and high levels of medicine usage can give valuable 'real-life' safety data. The types and frequencies of events reported reflected the types of events expected in patients prescribed antimalarials and nearly all events reported are listed in the summary of product characteristics of the medicines involved.