[Vitamin D and drugs].

Interactions between drugs and vitamin D have received only little or no attention in the medical and pharmaceutical world in the past. Since more and more drugs are used for the treatment of patients, this topic is increasingly relevant. As such interactions impact the health of the patient and the action and side effects of the drug, physicians and pharmacists should pay more attention to such interactions in the future. A number of drugs can interfere with the vitamin D and bone metabolism. The drug-induced activation of the pregnane X receptor (PXR) is likely to enhance CYP24 expression and the catabolism of 25(OH)D, leading to vitamin D deficiency. PXR-ligands include a wide variety of pharmaceutical agents, such as antiepileptic drugs, taxol, rifampicin, and human immunodeficiency virus protease inhibitors such as ritonavir and saquinavir. Beside this, the medication oriented supplementation of vitamin D can also ameliorate the pharmacologic action of many drugs, such as bisphosphonates, statins and cytostatic drugs.