Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some products that may interact with this drug include: digoxin, fingolimod, labetalol.

Other medications can affect the removal of diltiazem from your body, which may affect how this medication works. Examples include azole antifungals (such as ketoconazole), cimetidine, macrolide antibiotics (such as erythromycin), rifamycins (such as rifabutin, rifampin), St. John's wort, among others.

This medication can slow down the removal of other medications from your body, which may affect how they work. Examples of affected drugs include aprepitant/fosaprepitant, buspirone, colchicine, elacestrant, flibanserin, ivabradine, lomitapide, certain benzodiazepines (triazolam, midazolam), among others.

Some products have ingredients that could raise your heart rate or blood pressure. Tell your pharmacist what products you are using, and ask how to use them safely (especially cough-and-cold products, diet aids, or NSAIDs such as ibuprofen/naproxen).