Drug Interaction Report

Magnesium and aluminum antacids have been shown to reduce the area under the curve of zalcitabine. The mechanism has not been described but may be due to chelation or alteration in gastrointestinal pH. Zalcitabine should be administered 2 hours prior to a magnesium and/or aluminum-containing antacid. The clinical significance of this interaction is unknown.

ADJUST DOSING INTERVAL: Administration with food may increase the absorption of calcium. However, foods high in oxalic acid (spinach or rhubarb), or phytic acid (bran and whole grains) may decrease calcium absorption.

MANAGEMENT: Calcium may be administered with food to increase absorption. Consider withholding calcium administration for at least 2 hours before or after consuming foods high in oxalic acid or phytic acid.

Zalcitabine bioavailability may be decreased by 14% if taken with meals. The mechanism and clinical significance are unknown.