Cardizem (diltiazem) is a calcium channel blocker. It works by relaxing the muscles of your heart and blood vessels. Cardizem is used to treat hypertension (high blood pressure). Diltiazem is prescribed off-label by doctors in the US for prophylaxis of cluster headaches. Some research on diltiazem and other calcium channel antagonists in the treatment and prophylaxis of migraine is ongoing. Currently doctors in the US prescribe it off-label for such use. As well as the aforementioned conditions, Diltiazem is also used in the treatment of anal fissures. If taken topically in a cream it has shown increased effectiveness. Diltiazem is primarily used for controlling high blood pressure and treating chest pain in adults. This eMedTV page further discusses diltiazem uses, including how the drug works and several off-label uses of the medicine (such as treating migraines). This eMedTV Web page explains how Cardizem LA, a calcium channel blocker, works to control high blood pressure. This section also addresses possible off-label (unapproved) uses and whether children can take this medication. Cardizem is used for treating stable angina and variant angina. This part of the eMedTV library explains how the drug works and lists possible off-label Cardizem uses, such as for the treatment of irregular heart rhythms, migraines, and hypertension. Cardizem LA is used for relieving chest pain and lowering blood pressure. This eMedTV Web page discusses these Cardizem LA uses in more detail, explains whether the drug is approved for children, and also lists off-label uses of the medication. Cardizem CD uses are primarily focused on the treatment of high blood pressure and chest pain. As this eMedTV article explains, however, the drug can also be used off-label for treating migraines, arrhythmias, and diabetic nephropathy. Cardizem CD uses are primarily focused on the treatment of high blood pressure and chest pain. As this eMedTV article explains, however, the drug can also be used off-label for treating migraines, arrhythmias, and diabetic nephropathy. Many drugs have a variety of off-label uses. Perhaps the most recognized non-indicated use of diltiazem ER is for migraine prevention. Employing the drug for coronary bypass makes a certain amount of sense, too, because it helps the heart contract with greater ease.