The case for low dose diuretics in hypertension: comparison of low and conventional doses of cyclopenthiazide.

Abstract

In a double blind placebo controlled randomised parallel study the antihypertensive activity and adverse biochemical effects of three doses of cyclopenthiazide were evaluated in patients with mild essential hypertension that had been recently diagnosed or was being treated with a single drug. After a four week placebo washout period 53 patients with diastolic blood pressures between 90-110 mm Hg were randomly assigned to 50, 125, or 500 micrograms cyclopenthiazide or matching placebo for an eight week period of treatment. Blood pressure was measured in the patients' homes by the same observer every two weeks. Serum urea, electrolytes, urate, and creatinine concentrations and 24 hour urinary sodium excretion were monitored every four weeks and serum magnesium concentration and plasma renin activity at the end of the washout and treatment periods. After eight weeks of treatment systolic and diastolic blood pressures were significantly reduced in patients taking 125 and 500 micrograms cyclopenthiazide when compared with those taking placebo. The decrement in serum potassium concentration (0.6 mmol/l) and increase in serum urate concentration 0.06 mmol/l) were greatest with the 500 micrograms dose, the increase in serum urate concentration alone being significant. No change in serum magnesium concentration or 24 hour urinary sodium excretion was noted with any dose of cyclopenthiazide. Only the 500 micrograms dose of cyclopenthiazide significantly increased the mean plasma renin activity (1.8 (95% confidence interval 0.2 to 3.4)-5.4 (3.9 to 6.8) nmol angiotensin I/l/h); the other doses like the placebo had no effect. Cyclopenthiazide 125 micrograms, a dose lower than is currently marketed, produced a similar hypotensive response to 500 micrograms of the drug without upsetting the biochemical profile.

• Authors: G McVeigh, D Galloway, D Johnston
• Journal: BMJ (Clinical research ed.) (BMJ) Vol. 297 Issue 6641 Pg. 95-8 (Jul 09 1988) ISSN: 0959-8138 [Print] England
• PMID: 3044503 (Publication Type: Clinical Trial, Journal Article, Randomized Controlled Trial)

Chemical References

• Diuretics
• Sodium Chloride Symporter Inhibitors
• Sodium
• Cyclopenthiazide

Topics

• Aged
• Clinical Trials as Topic
• Cyclopenthiazide (administration & dosage, adverse effects, therapeutic use)
• Diuretics
• Dose-Response Relationship, Drug
• Double-Blind Method
• Drug Administration Schedule
• Female
• Humans
• Hypertension (drug therapy, urine)
• Male
• Middle Aged
• Random Allocation
• Sodium (urine)
• Sodium Chloride Symporter Inhibitors (administration & dosage)