Prescription patterns and utilisation of antihypertensive drugs in a specialist hospital in Port-Harcourt

Abstract

The aim of the study is to investigate the prescribing pattern and drug use in the management of essential hypertension in a specialist hospital and its conformity to the JNC VII and WHO/ISH management guidelines. A total of 1572 prescriptions from 490 case files of hypertensive patients (> 18 years) attending the Out-patients Departments of a Specialist Hospital between May and October 2012, were retrospectively surveyed. The most prescribed antihypertensive drug class was calcium channel blockers (32.44%), followed by ACE Inhibitors, (18.06%), diuretics (13.93%), fixed dose combinations (10.75%) and anxiolytics and low dose Aspirin grouped as others (14.12%). Individually, amlodipine (26.53%) was the most prescribed drug followed by Lisinopril (13.36%), hydrochlorothiazide + amiloride (Moduretic) (12.02%), Lexotan (9.29%), hydrochlorothiazide + Valsatan (Co-Diovan)(6.42%), nifedipine (5.92%), and methyldopa (5.53%). Combination therapy (73.38%) was used more commonly than monotherapy (22.50%). Among the combination therapies, 2- drug therapy (28.97%) was more preferred while the 3-drug and 4-drug therapies of diuretic + 2 drugs and Fixed Dose Combination + 2 drugs (11.62% each) were most commonly used. The study also shows that, of the 680 numbers of encounters, there were a total of 1544 drugs and 28 non-drug interventions. The average number of drugs per encounter was 2.3. The percentage of drug prescribed by generic name is 31.2% (482), while the percentage of encounter with antibiotics and injections was 0.7% each. The pattern of antihypertensive utilization complied partially with the JNC 7 Guideline and WHO/ISH 1999 Guidelines but did not conform to the Essential Drug List Act of Nigeria.

Keywords: Antihypertensives, prescription pattern, drug utilization, treatment guideline