The effects of dihydrotachysterol can persist for up to one month after cessation of treatment. Manifestations: Toxicity associated with dihydrotachysterol is similar to that seen with large doses of vitamin D. Overdosage is manifested by symptoms of hypercalcemia, i.e., weakness, headache, anorexia, nausea, vomiting, abdominal cramps, diarrhea, constipation, vertigo, tinnitus, ataxia, hypotonia, lethargy, depression, amnesia, disorientation, hallucinations, syncope, and coma. Impairment of renal function may result in polyuria, polydipsia, and albuminuria. Widespread calcification of soft tissues, including heart, blood vessels, kidneys, and lungs, can occur. Death can result from cardiovascular or renal failure. Treatment: Treatment of overdosage consists of withdrawal of dihydrotachysterol, bed rest, liberal intake of fluids, a low-calcium diet, and administration of a laxative. Hypercalcemic crisis with dehydration, stupor, coma, and azotemia requires more vigorous treatment. The first step should be hydration of the patient. Intravenous saline may quickly and significantly increase urinary calcium excretion. A loop diurectic (furosemide or ethacrynic acid) may be given with the saline infusion to further increase renal calcium excretion. Other reported therapeutic measures include dialysis or the administration of citrates, sulfates, phosphates, corticosteroids, EDTA (ethylenediaminetetraacetic acids), and mithramycin via appropriate regimens.