Pattern of drug utilization among hypertensives in a Nigerian teaching hospital

To describe the drug utilization pattern among hypertensive patients in a tertiary care setting, assess the short-term outcome of anti-hypertensive drugs usage and identify points for future intervention to improve outcomes.

A cross sectional retrospective drug use review was conducted between 1st June and 31st August 2002 on randomly selected 200 case notes of hypertensive patients at a tertiary care facility in South-Western Nigeria.

Diuretics were the most frequently prescribed anti-hypertensive class (39.4%), followed by centrally acting agents (23.3%), calcium channel blockers (21%), angiotensine converting enzyme (ACE) inhibitors (8.6%) and beta blockers (1.9%). Aspirin was the most frequently prescribed adjoining non-anti-hypertensive drugs (39.7%), followed by anxiolytics (23.6%), other non-steroidal anti-inflammatory drugs (NSAIDs) (14.8%), metformin (6.7%), glibenclamide (5.9%), paracetamol (5.9%) and Mist. Magnesium Trisilicate (3.3%). All patients made out-of-pocket payments for their prescribed anti-hypertensive drugs at the study site. Blood pressure control was adequate in only 33.9% of patients. There was no significant difference in blood pressure control between male and female hypertensives ( p > 0.05). Anti-hypertensive drugs were changed at least once in 44% of patients and blood pressure control was significantly better in patients with at least one change ( p < 0.05). Adherence with drug therapy was documented as adequate in 82.5% of patient. Diabetes mellitus (NIDDM) (39.6%) and osteoarthritis (22.9%) were the most frequent co-morbidities. Potential harmful drug interactions were identified in 3.8% (49) of patients.

Diuretics and centrally acting agents were the most frequently prescribed anti-hypertensive drugs in a tertiary care setting in Nigeria. Physicians' prescribing decisions appear significantly influenced by cost consideration.