[Use of antihypertensive drugs in Spain, 1985-1995].

BACKGROUND

This study has analysed the trend of antihypertensive drugs consumption in Spain from 1985 to 1995, its economical impact and the correlation with the available scientific evidence. The utilization of calcium channel blockers in the context of the recent controversial about their safety profile was also evaluated.

METHODS

Drugs from the ATC groups C02, C03 (excluding C03C), C07, C08 (excluding nimodipine and nicardipine) and C09 were included (ATC classification, 1996 version). Drug utilization data and cost figures were obtained from the databases ECOM and FAR-90 of the Ministry of Health. These databases contain the number of packages sold in community pharmacies that are charged to the National Health System. Data are expressed in defined daily doses per 1,000 inhabitants per day (DHD). The cost is expressed in current and constant pesetas.

RESULTS

The use of antihypertensives increased from 34.78 DHD in 1985 to 103.55 DHD in 1995. Angiotensin-converting enzyme inhibitors (ACEI) and calcium channel blockers (CCB) are responsible for 89% of the total increase. Thiazides and beta-blockers showed a mild increase, although its relative contribution to the total figures declined from 72 to 32% at the end of the period. Rauwolfia alcaloids and antiadrenergic drugs sales were negligible (0.4% of total sales in 1995). Within the thiazides, consumption was concentrated in products containing > or = 50 mg hydrochlorothiazide or equivalent. Enalapril, captopril, nifedipine and the fixed-dose association of hydrochlorothiazide with amiloride were the most widely used drugs. The cost of antihypertensive drugs in current pesetas raised eight times through the study period reaching 105,501 millions pesetas in 1995; 89% of the cost corresponded to ACEI and CCB. Expressed in constant pesetas the cost increase was four fold. The recent controversia about CCB did not have influence on its consumption.

CONCLUSIONS

The pattern of use of antihypertensive drugs in Spain does not follow the available scientific evidence. Drugs with less documented effectiveness are the most prescribed; even considering the same effectiveness, efficiency is lower for drugs with higher utilization rates. The available presentations for thiazides makes their utilization in the optimal dosification difficult.