Amoxycillin and co - trimoxazole in presumed viral respiratory infections of childhood : placebo - controlled trial

It has been suggested that patients with essential hypertension may fall into three groups8: those with high renin levels, who respond best to beta-blockers; those with low renin levels, who respond best to diuretics; and those with normal renin, who respond equally to beta-blockers or diuretics. We could not identify any such subgroups in these few patients or any biochemical of physical marker that could have predicted a response to a diuretic or beta-blocker. Certainly atenolol had a greater hypotensive effect than bendrofluazide in some patients, but an equal number did better with bendrofluazide than with atenolol. This difference in response bore no relation to the hyporeninaemic effect of atenolol. The decision to include patients with severe hypertension in a trial incorporating a placebo period was not taken lightly. Most of the patients in the trial were referred to us because they were not being controlled satisfactorily on existing regimens and it was not clear whether this was due to the regimens themselves or to lack of patient compliance. We regarded it as essential to establish the true level of untreated blood pressure and the degree of patient compliance by having a closely supervised placebo period and incorporating a riboflavin marker into one of the tablets. We found that the pressure levels recorded during our placebo period differed little from those achieved when the patients were on their previous "treatment" regimens. The agent of first choice for treating hypertension is likely to depend on many factors. So far as atenolol and bendrofluazide are concerned there was no significant difference in their effect on systolic blood pressure, although atenolol was more effective than bendrofluazide on diastolic blood pressure (P <0-05). The biochemical effects produced by the two agents may, however, be important in deciding which should be regarded as first-choice treatment. The acute and long-term effects of bendrofluazide (hypokalaemia, hyperuricaemia, and a tendency towards hyperglycaemia) are well known but are clinically not important. The long-term effects of atenolol are not yet known but it appears to have several, possibly advantageous biochemical effects-for example, reduction in plasma renin, a slight increase in serum potassium, and a small reduction in urate. It remains to be seen whether atenolol confers the same benefit in respect of myocardial infarction as has been shown with practolol9 and alprenolol.10 11