Antihypertensive drug utilization and conformity to guidelines in a sub-Saharan African hypertensive population

Despite availability and usage of wide array of antihypertensive drugs, blood pressure has remained poorly controlled in most health care settings particularly in Africa. The cost of these drugs among other factors strongly determines the prescription and usage pattern which ultimately affects control of blood pressure particularly in sub-Saharan Africa. The aim of this study was to describe the current utilization pattern of antihypertensive drugs in a tertiary hospital in Nigeria in line with the regional and international guidelines for hypertension management and to compare with similar studies in other parts of the country to generate the national outlook.

This is a cross sectional study of 805 adult hypertensive patients who were on treatment at the Medical Out-Patient Department of University of Ilorin Teaching Hospital in Nigeria, a country with the most populous black hypertensive patients. Data were collated from the patients' records and evaluated according to drug classifications.

787 patients out of the 805 evaluated were eventually included in the analysis. Mean age was 57.88 + or - 12.59 years with 490 (62.3%) females. Frequency of use of classes of antihypertensive was: diuretics (D, 84%), calcium channel blockers (CCB, 66%), angiotensin converting enzyme inhibitors (ACEI, 65%), a-methyldopa (ALD, 26%), beta-blockers (BB, 11.9%) and angiotensin receptor blockers (3.8%). Proportions of number of drugs usage per patient were: 0 (2.2%), 1 (9.1%), 2 (37.1%), 3 (35.8%), 4 (15.6%), and 5 (0.1%). The most commonly used combinations of drugs were ACEI + CCB + D (21.6%), followed by CCB + D (14.5%), ACE + D (11.4%) and ACEI + D + ALD (9.8%). Other recent studies in Nigeria revealed diuretics and multiple agents as the prevalent prescription pattern.

Antihypertensive utilization in Ilorin, Nigeria like some parts of the country conforms to the guidelines for the management of hypertension in blacks with majority of patients on diuretics particularly in combination with other agents. Angiotensin converting enzyme inhibitors are increasingly being used whereas beta-blockers and angiotensin receptor antagonists are still less utilized.