- Precautions to be taken in case of severe peripheral circulation disorders, diabetes (especially at the time, when blood sugar is elevated), during a strict fast, in case of metabolic acidosis, atrioventricular block (AV) block of grade I, Prinzmetal angina, additional therapy with angiotensin-converting enzyme inhibitors (ACE-inhibitors), severe coronary or cerebral sclerosis, hyperuricemia or gout and in subjects with a history of severe hypersensitive reactions or during a desensitization therapy (excessive anaphylactic reaction, attenuated adrenergic counterregulation)