SN Instructed patient about the Ergocalciferol is vitamin D2. Vitamin D is important for the absorption of calcium from the stomach and for the functioning of calcium in the body.Possible hypervitaminosis D effects: polyuria, nocturia, polydipsia, hypercalciuria, reversible azotemia, hypertension, nephrocalcinosis, generalized vascular calcification, irreversible renal insufficiency (may be fatal), mental retardation, widespread soft tissue calcification, osteoporosis, dwarfism, vague aches, stiffness, weakness, nausea, anorexia, constipation, mild acidosis, anemia, weight loss.