When used concomitantly with digitalis preparations, the risk of heart rhythm disorders increases, with antacids-the risk of hypermagnesemia, with calcium preparations and thiazide diuretics — the risk of hypercalcemia.
Combined use with barbiturates, anticonvulsants and other drugs that activate microsomal oxidation enzymes in the liver requires the use of a higher dose of alfacalcidol.
Mineral oil (when used together for a long time), colestyramine, colestipol, sucralfate, antacids, albumin preparations reduce the absorption of alfacalcidol.