Experience with overdosage in humans is limited. Headache, diarrhea, hypotension, tachycardia and/or cardiac arrhythmias may occur. Treatment is symptomatic and supportive. Hemodialysis is unlikely to be of value. In some animal models, high-dose or long-term administration was associated with a variety of cardiovascular lesions; including endocardial hemorrhage, hemosiderin deposition and left ventricular fibrosis, coronary arteritis, and periarteritis.