Signs of an allergic reaction, including an unexplained rash, hives, itching, unexplained swelling, wheezing, or difficulty breathing or swallowing.
Rare Diltiazem Side Effects
There are other possible diltiazem side effects that can occur. These rare side effects occur in less than 2 percent of people taking the medication. For these side effects, it is difficult to tell whether the side effect is actually caused by diltiazem or something else.
Some of these rare diltiazem side effects include, but are not limited to:
Flushing (redness of the skin, especially the face)