Fifty years of progress with antithrombotic drugs--with much more to come: a perspective

Glucose tolerance and postprandial glucose and insulin kinetics in rats with short- and long-term alpha 1-adrenergic blockade

The present study was designed to evaluate the acute and chronic effects of the alpha 1-adrenergic antagonist prazosin (Praz) on glucose tolerance and on postprandial plasma glucose and insulin kinetics. Rats were fed a high sucrose diet for 3 weeks, to which Praz (3 mg/kg/day) was added or not. They were then accustomed to ingest a meal 1 h after a single intraperitoneal (i.p.) injection of saline or Praz (1 mg/kg). Plasma levels of glucose and insulin were recorded at various times after meal intake. In addition, a fasting intravenous glucose tolerance test (IVGTT) was performed. In the chronic control cohort, pre-IVGTT plasma glucose and insulin levels were slightly but significantly higher after acute Praz than after acute saline administration. Factorial analysis of variance (ANOVA) showed that the increase in plasma glucose and insulin after intravenous (i.v.) glucose administration was also slightly greater in the animals that received acute Praz than in their saline counterparts. In contrast, after chronic treatment with Praz, pre- and post-IVGTT plasma glucose and insulin concentrations were identical in groups acutely injected with saline or Praz. In the chronic control cohort, preprandial plasma glucose and insulin measured in a sample collected before acute injection of saline or Praz were similar in both groups. The postprandial increase in plasma glucose and insulin was potentiated by the acute administration of Praz. Fasting plasma glucose and insulin concentrations were also similar in both groups chronically treated with Praz, and acute administration of the blocker still potentiated the increase in plasma glucose and insulin that followed meal intake. Chronic treatment alone did not affect postprandial glucose and insulin concentrations, and acute injection of Praz had comparable effects whether rats were chronically treated with the blocker or not. Therefore, potentiation of the glucose and insulin response to meal intake by Praz persisted after chronic treatment but required the acute presence of the blocker. However, repeated exposure to acute bouts of postprandial hyperinsulinemia induced by Praz did not lead to deterioration of insulin sensitivity or of the capacity of the pancreas to secrete insulin, as suggested by a normal response of glucose and insulin to IVGTT.

Quality of life in hypertensive patients treated with either carvedilol or enalapril

An important aspect of antihypertensive drug treatment is quality of life (QL) which should at least not be negatively affected. In this study, the QL during treatment with carvedilol (C), a beta-blocker with vasodilating properties due to alpha-1-receptor blockade, was compared to that of enalapril (E) in patients who had responded to the treatment.

PATIENTS AND METHODS

Patients with mild to moderate hypertension (diastolic blood pressure 95-115 mmHg) were randomised to receive either E(n = 119) of C(n = 129) in a double-blind multicenter study. The starting doses were 12.5 (C) and 10 (E) mg with doubling of the dose if necessary at 3-week intervals. If insufficient blood pressure (BP) control was found at 50 mg C or 40 mg E, 12.5 mg of hydrochlorothiazide was added. After having reached the goal BP the patients entered a 5-months maintenance period. General well-being was evaluated by the "Göteborg Quality of Life Questionnaire".

RESULTS

Equally many patients in the respective treatment groups responded at the different dose levels. Diastolic BP after 5 months in the maintenance period was similar on C and E, respectively. For most items, QL was not affected by the treatments. An increased incidence of cough was perceived in the E group (p < 0.001). None of the C treated patients reported frequent cough at the end of the study compared with 12% of E treated patients.

CONCLUSION

C and E had similar BP lowering effects. Neither treatment seemed to affect the patients QL adversely. Cough, although seldom leading to withdrawal from the therapy, may be more common than is commonly recognised during treatment with ACE-inhibitors.