Mibefradil (Systemic)

Before Using This Medicine

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For mibefradil, the following should be considered:

Allergies - Tell your doctor if you have ever had any unusual or allergic reaction to mibefradil. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy - Mibefradil has not been studied in pregnant women. However, studies in animals have shown that large doses of mibefradil can cause heart defects in rat fetuses. Before taking this medicine, make sure your doctor knows if you are pregnant or may become pregnant.

Breast-feeding - It is not known if mibefradil passes into breast milk, however, it passes into the milk of lactating rats. Newborn babies have been reported to be sensitive to other calcium channel blocking agents. Be sure you have discussed the risks and benefits of this medicine with your doctor.

Children - Although there is no specific information comparing use of mibefradil in children with use in other age groups, it is not expected to cause different side effects or problems in children than it does in adults.

Older adults - Elderly people may be more sensitive to the heart rate slowing effects of mibefradil.

Other medicines - Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking mibefradil, it is especially important that your health care professional know if you are taking any of the following:

• Astemizole (e.g., Hismanal) or
• Cisapride (e.g., Propulsid) or
• Terfenadine (e.g., Seldane) - These medicines should not be used with mibefradil because unwanted effects of these medicines on the heart may be increased

• Atorvastatin (e.g., Lipitor) or
• Cerivastatin (e.g., Baycol) or
• Lovastatin (e.g., Mevacor) or
• Simvastatin (e.g., Zocor) - These medicines should not be used with mibefradil because unwanted effects of these medicines, such as muscle aches or cramps (rhabdomyolysis), may be increased and may lead to development of kidney problems

• Beta-adrenergic blocking agents (acebutolol [e.g., Sectral], atenolol [e.g., Tenormin], betaxolol [e.g., Kerlone], carteolol [e.g., Cartrol], carvedilol, [e.g., Coreg], labetalol [e.g., Normodyne], metoprolol [e.g., Lopressor], nadolol [e.g., Corgard], oxprenolol [e.g., Trasicor], penbutolol [e.g., Levatol], pindolol [e.g., Visken], propranolol [e.g., Inderal], sotalol [e.g., Sotacor], timolol [e.g., Blocadren]) or
• Digitalis glycosides (e.g., Lanoxin) or
• Diltiazem (e.g., Cardizem) or
• Verapamil (e.g., Calan) - Effects to slow the heart rate may be increased

• Cyclosporine (e.g., Sandimmune) or
• Desipramine (e.g., Norpramin) or
• Imipramine (e.g., Tofranil) or
• Tacrolimus (e.g., Prograf) - Effects of these medicines may be increased if they are used with mibefradil

• Flecainide (e.g., Tambocor) or
• Propafenone (e.g., Rythmol) - Unwanted effects of these medicines on the heart may be increased

Other medical problems - The presence of other medical problems may affect the use of mibefradil. Make sure you tell your doctor if you have any other medical problems, especially:

• Heart rhythm or heart rate problems - Mibefradil can worsen these conditions