Late effect of tobanum and tobanum + furosemide therapy on the glucose tolerance of patients and on the insulin response to oral glucose doses.

The authors examined the effect of beta-blocker monotherapy (Tobanum tab = 5 mg cloranololum hydrochloricum) and beta-blocker + diuretic (Tobanum + Furosemide) combination therapy on glucose tolerance and insulin secretion in response to oral glucose doses in hypertensive non-diabetic patients. Twenty-six patients were examined (13 men, 13 women). The patients were followed up for 28 weeks after a 2-week drug-free period. The hypotensive dose was adjusted individually within 4 weeks. Oral glucose tolerance test and immuno-reactive insulin determination were performed concurrently before starting hypotensive therapy and on weeks 6, 14, and 28 of therapy. The results of the examinations were evaluated separately in two patient groups. Fifteen patients were given daily 10-20 mg Tobanum (Group I) while 11 patients received daily 10-20 mg Tobanum + 40-80 mg Furosemide (Group II). The glucose area of patients on Tobanum monotherapy did not change, insulin secretion decreased gradually (from 804 to 495 pmol/l). The decrease was significant (p less than 0.05). The glucose area of Tobanum + Furosemide-treated patients increased from 13.2 +/- 3.2 mmol/l to 16.1 + 4.9, the insulin secretion decreased from 1039 + 339 to 706 + 411 pmol/l during therapy (p less than 0.02 and p less than 0.05, resp.). When evaluating the results the decrease of insulin secretion is attributed to Tobanum effect while the deterioration of glucose tolerance may be correlated to the action of Furosemide on extrapancreatic metabolism.