Enchancement of polyuria by glibenclamide in diabetes insipidus

Divergent cardiac effects of the first and second generation hypoglycemic sulfonylurea compounds

The effects of first and second generation hypoglycemic sulfonylureas on the incidence of ventricular ectopic beats and on the duration of transitional ventricular fibrillation in the ischemic rat heart were investigated. First generation sulfonylurea compounds (tolbutamide, carbutamide and gliclazide) in 105 preparations increased, while second generation sulfonylurea compounds (glibenclamide and glipizide) in 50 preparations decreased in a dose-dependent manner both the number of ventricular ectopic beats and the duration of transitional ventricular fibrillation during the first 30 min after ligation of the left anterior descending coronary artery. Therefore, second generation sulfonylureas should be preferred in the treatment of type 2 diabetics with ischemic heart diseases, if satisfactory metabolic control cannot be achieved by a treatment regimen and diet alone.

Effects of various hypoglycaemic sulphonylureas on the cardiotoxicity of glycosides

In diabetic patients it has been shown that tolbutamide and carbutamide enhanced and glibenclamide did not influence the incidence of digitalis intoxication, or that of multifocal ectopic beats or coupling due to premature ectopic ventricular beats during digitalis therapy. In rabbits glibenclamide decreased and tolbutamide and carbutamide increased strophanthidin toxicity in a dose dependent manner. It was concluded that glibenclamide should be preferred to tolbutamide or carbutamide in digitalis-treated diabetics, when satisfactorily metabolic control is not achieved with a dietary regime alone.

Drug management of antidiuretic hormone imbalance following pituitary surgery

ADH imbalance may occur in patients after pituitary surgery. Two cases are presented that demonstrate the problems associated with the disturbance of water metabolism. The medical management of these patients is discussed, with emphasis on the importance of the correct choice of pharmacological agents to control the manifestations of ADH imbalance.

Drug-induced electrolyte disorders

A wide variety of pharmacologic agents have been implicated in a number of electrolyte disorders. The present review focuses on abnormalities of sodium, potassium, calcium, magnesium, and phosphate. Several mechanisms are involved in the pathogenesis of these disorders. These involve stimulation and modulation of other hormones (e.g., antidiuretic hormone, renin-angiotensin system, parathyroid hormone), damage to renal tubules, and, in some cases, a combination of factors. Recognition of these abnormalities is important because their presence may be life threatening or may aggravate the side effects of the drug itself.

Electrophysiological effects of hypoglycaemic sulphonylureas on rabbit heart

The hypoglycaemic sulphonylurea drugs glibenclamide and carbutamide were compared as to their influence on the electrical activity of isolated rabbit heart preparations. Carbutamide (10(-5)-10(-3) M) was found to depress slightly the nomotopic and junctional automaticity, while in Purkinje fibres it enhanced automaticity and conduction velocity. On the other hand, glibenclamide (10(-6)-10(-3) M) had no significant influence on the nomotopic and junctional automaticity, and markedly depressed automaticity and conduction velocity in the Purkinje fibres. The atrial conduction system was not much influenced by the sulphonylureas tested. Carbutamide depressed the electrical threshold in Purkinje fibres. It follows that the hypoglycaemic sulphonylurea compounds carbutamide and glibenclamide differ considerably with respect to their influences on cardiac electrical activity.