The main adverse drug reaction associated with<unk>  therapy is hypercalcemia – early symptoms include: nausea, vomiting, constipation, anorexia, apathy, headache, thirst, pruritus, sweating, and/or polyuria. Compared to other vitamin D compounds in clinical use (cholecalciferol, ergocalciferol),<unk>  has a higher risk of inducing hypercalcemia. However, such episodes may be shorter and easier to treat due to its relatively short half-life. High<unk>  levels may also be seen in human disease states in patients not on supplementation. In someone with hypercalcaemia and high<unk>  levels, low intact parathyroid hormone levels are usually present. The major conditions with hypercalcaemia due to elevated<unk>  levels are lymphoma, tuberculosis and sarcoidosis where excess production occurs due to ectopic 25(OH)D-1-hydroxylase (CYP27B1) expressed in macrophages. Other conditions producing similar findings including: * Fungal infections; Pneumocystis jiroveci, histoplasmosis, coccidioidomycosis, paracoccidioidomycosis, candidiasis * Other granulomatous conditions; PR3+ vasculitis, Crohn's disease, acute granulomatous pneumonia, talc granuloma, silicone-induced granuloma, BCG-associated, granulomatous hepatitis, paraffin-associated granuloma * Genetic conditions; Williams syndrome, pseudoxanthoma elasticum, CYP24A1 mutation (adult / infantile), SLC34A1 mutation * Miscellaneous; mycobacterium avium, leprosy, lipoid pneumonia, cat scratch fever, berylliosis Some plants contain glycosides of 1,25-dihydroxycholecalciferol. Consumption of these glycosides by grazing animals leads to vitamin D toxicity, resulting in calcinosis, the deposition of excessive calcium in soft tissues. Three rangeland plants, Cestrum diurnum, Solanum malacoxylon, and Trisetum flavescens are known to contain these glycosides. Of these, only Cestrum diurnum is found in the U.S., mainly in Florida.
Calcitriol
Parathyroid hormone
Estriol
Estriol 
Parathyroid hormone-related protein
Cholecalciferol
Ergocalciferol
Calcipotriol