Since calcitriol exerts vitamin D activity, adverse effects may occur which are similar to those found when an excessive dose of vitamin D is taken ie, hypercalcemia syndrome or calcium intoxication (depending on the severity and duration of hypercalcemia). Occasional acute symptoms include anorexia, headache, vomiting and constipation. Chronic effects may include dystrophy, sensory disturbances, fever with thirst, polyuria, apathy, arrested growth and urinary tract infections.