Do not use this medication if you have certain heart conditions such as "sick sinus syndrome” or "AV block” (unless you have a pacemaker), low blood pressure, or if you have recently had a heart attack.
Before taking diltiazem, tell your doctor if you are allergic to any drugs, or if you have kidney disease, liver disease, or congestive heart failure.
Diltiazem can cause side effects that may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be awake and alert.
Do not stop taking this medication without first talking to your doctor. If you stop taking diltiazem suddenly, your condition may become worse.
Diltiazem may be only part of a complete program of treatment that also includes diet, exercise, and other medications. Follow your diet, medication, and exercise routines very closely.
If you are being treated for high blood pressure, keep using this medication even if you feel fine. High blood pressure often has no symptoms.