Factors influencing over and under-consumption of anti-hypertensive drugs.

Using a self-administered questionnaire, 817 patients attending two hypertension clinics were questioned about the number of tablets of different hypotensive drugs they took every day. The answers were compared with the number of tablets they should have been taking to determine the proportion who were not compliant with individual drug therapy. Ten per cent reported they were taking less than they should and seven per cent were taking more. Obsessionality was determined from a psychological questionnaire and non-compliant patients had a lower average score than compliant patients. Symptomatic side-effects associated with bethanidine appeared to induce non-compliance. Two symptoms were associated with failure to take the prescribed number of tablets, faintness on standing and a lessened interest in sex. This latest survey showed an improvement in compliance with most drugs compared with previous unpublished surveys conducted in 1971 to 1976. Once daily diuretic regimes were associated with better compliance than more complicated drug regimens.