Low-dose clonidine administration in the treatment of mild or moderate essential hypertension: results from a double-blind placebo-controlled study (Clobass). The Clobass Study Group.
Five hundred and fifty-nine hypertensive outpatients with diastolic blood pressure between 95 and 110 mmHg participated in this double-blind, placebo-controlled, multicenter study. Eligible subjects were randomly allocated to receive either clonidine (75 micrograms twice daily) or a placebo. After 4 weeks, 'responders' to treatment (diastolic blood pressure reduced to less than or equal to 90 mmHg or by greater than or equal to 10 mmHg) were kept on monotherapy and checked at 4-weekly intervals for another 3 months. Non-responders were given 15 mg chlorthalidone and were also checked for a further 3 months. At the end of the first month, 54.2% of the subjects were responders to clonidine and 41.5% were responders to the placebo (P less than 0.05 for both groups). Of the remaining patients, 69.0% became responders to clonidine plus chlorthalidone, whereas only 34.7% were responders to placebo plus chlorthalidone (P less than 0.01 for both groups). Withdrawals from the study because of excessive diastolic blood pressure levels were about eight times less frequent among the subjects treated with clonidine, either alone or with chlorthalidone. Dry mouth was twice as frequent in the clonidine-treated patients, but there was no significant difference in the incidence of all side effects or the number of withdrawals from the study because of side effects between the two groups. We conclude that low-dose clonidine is effective in the treatment of mild or moderate hypertension. Clonidine-related side effects are still evident, but the overall tolerance profile for this reduced dosage of the drug appears to be favorable.
D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000187:drug effects; D002752:Chlorthalidone / Q000627:therapeutic use; D003000:Clonidine / Q000008:administration & dosage* / Q000627:therapeutic use; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D007558:Italy; D008297:Male; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D013997:Time Factors
D003000:Clonidine; D002752:Chlorthalidone