Antihypertensive drug prescription trends at the primary health care centres in Bahrain.

PURPOSE

To determine the antihypertensive drug prescribing pattern by primary care physicians in patients with uncomplicated essential hypertension; to identify whether such pattern of prescription is appropriate and in accordance with international guidelines for pharmacotherapy of hypertension; and to estimate the impact of such prescriptions on cost of treatment.

METHODS

A prescription-based survey among patients with uncomplicated essential hypertension was conducted in seven out of a total of 18 health centres in Bahrain. The relevant data for our study was collected using cards, designed for chronically-ill patients.

RESULTS

A total of 1019 male and 1395 female (62.9%) out of 3838 of the study population were on monotherapy, whereas 596 male and 828 female (37.1%) were on antihypertensive combination therapy. Among the monotherapy category, the various antihypertensive drugs used were as follows: beta-blockers (58.8%), angiotensin converting enzyme (ACE) inhibitors (14.2%), calcium channel blockers (11.1%), diuretics (8.1%) and alpha-methyldopa (7.0%). With respect to overall utilization pattern, beta-blockers were the most frequently prescribed (65.5%), diuretics ranked second (27.4%), followed by ACE inhibitors (20.6%), calcium channel blockers (19.9%) and alpha-methyldopa (8.5%). Within each class of antihypertensives used, the most frequently used individual agents were as follows: (a) among beta-blockers 97.7% used atenolol; (b) among the diuretics, indapamide (35.4%), hydrochlorothiazide (HCTZ) (32.7%), HCTZ in combination with triamterene (25.7%), and chlorthalidone (4.6%); (c) among the ACE inhibitors, captopril (44.9%), enalapril (29.7%), and lisinopril (19.0%); (d) among the calcium channel blockers, nifedipine (98.2%). Significant age- and gender-related differences in prescribing patterns were seen. Short-acting nifedipine monotherapy was inappropriately prescribed in a significant number of patients above the age of 50 years. ACE inhibitors accounted for approximately two-thirds of the total antihypertensive drug expenditure, although these drugs represent only one-fifth of overall antihypertensives used. There is a trend towards excessive use of expensive thiazide-like diuretics such as indapamide which seems to be unjustifiable practice, particularly in a study population free from diabetic hypertensive patients.

CONCLUSIONS

The general pattern of antihypertensive utilization appears to be in accordance with the guidelines of WHO and the Joint National Committee issued in the 1990s. The trends of prescribing of antihypertensives were in favour of conventional ones such as the beta blockers and diuretics, and the introduction of newer classes of antihypertensives had a generally minimal impact on the prescribing profile. Almost two-thirds of the patients were treated with monotherapy. A disproportionately large percentage of antihypertensive drug cost was due to overt use of ACE inhibitors, and indapamide, instead of thiazide diuretics. The use of short-acting calcium channel blockers especially in the elderly is unjustifiable.