A Profile of Adverse Effects of Antihypertensive Medicines in a Tertiary Care Clinic in Nigeria

BACKGROUND There has been a dearth of comprehensive data on the profile of adverse reactions to antihypertensive medicines in the Nigerian setting despite increased use. OBJECTIVE This study was aimed to characterize the adverse reactions experienced in the homogenously black African population. METHODS The study was carried out at the University of Benin Teaching Hospital, Benin City, Nigeria, in consenting eligible hypertensive patients ≥18 years. Adverse reactions were sought using patient's self-report and a medicine-induced symptom checklist. RESULTS A total of 514 patients (340 females) aged 22-97 years were studied. Thirteen percent, 27.6%, 26.7%, 22.0%, and 10.7% were on 1, 2, 3, 4, and ≥5 medicines, respectively, for control of their blood pressure with the frequency of adverse effects increasing proportionately up to four medicines. Adverse reactions to antihypertensive medicines were reported by a total of 93 (18.1%) patients. Diuretics - 27.9%, calcium channel blockers (CCBs) - 26.8%, and angiotensin-converting enzyme inhibitors (ACEIs) - 26.8% accounted for most of the adverse reactions seen, notably frequent micturition and headaches (CCB); excessive micturition and dizziness (diuretics); dry irritating cough (ACEI). Notable complaints for all patients using the checklist were increased frequency of micturition, reduction in libido, and headaches. The reactions resulted in the discontinuation and substitution of therapy in 49.5% of the patients. CONCLUSIONS The characterization of these reactions in Nigerians requires further studies as frequent micturition reported is still a neglected complaint in antihypertensive therapy.