Long-term high-dose cholecalciferol in patients with heavy proteinuria.

Four patients presenting with heavy proteinuria, vitamin D deficiency and secondary hyperparathyroidism were treated with cholecalciferol for 1.5-3 years. Doses of 7143-14286 U/day were necessary to achieve the calcidiol target of >75 nmol/L. The effect of dosing on calcidiol levels was inconsistent and there was no apparent relationship between changing calcidiol levels and intact parathyroid hormone (PTH) levels. Toxicity was not observed. This series suggests high doses of cholecalciferol over a prolonged period of time are necessary to achieve recommended calcidiol levels; however, the lack of an impact on PTH casts doubt on the suitability of the calcidiol target, in patients with heavy proteinuria.