Diltiazem

Brand names

• Albert Diltiazem CD
• Apo-Diltiaz
• Alti-Diltiazem
• Cardizem
• Cardizem CD
• Cardizem SR
• Cartia XT
• Dilacor XR
• Diltia XT
• Diltiazem
• Diltiazem ER
• Gen-Diltiazem
• Med Diltiazem SR
• Novo-Diltiazem
• Nu-Diltiaz
• Pharma-Diltiaz
• Rhoxal-Diltiazem CD
• Syn-Diltiazem
• Teczem [CD]
• Tiamate
• Tiazac

Usage

To relieve and control angina (chest pain associated with heart disease), to reduce high blood pressure, and to correct heartbeat irregularities (cardiac arrhythmia).

How it works

Diltiazem interferes with the movement of calcium into heart muscle cells and the smooth muscle cells in the walls of the arteries. This action relaxes blood vessels (causing them to widen), which lowers blood pressure, increases the blood supply to the heart, and decreases the heart's overall workload.

Side effects

Serious

Irregular or slow heartbeat, shortness of breath, and fatigue caused by heart failure.

Common

Headache, drowsiness, swelling of feet and ankles, constipation, nausea, sudden weight gain, fatigue.

Less common

Dizziness, weakness, depression, nervousness, insomnia, confusion, slow pulse, vomiting, diarrhea, excessive urination, itch, sensitivity to sunlight, yellowish tinge to eyes or skin due to liver failure, skin rash, overgrowth of the gums.

Possible interactions

Other medicaments:

Diltiazem taken concurrently with:

• alfentanil (various) may lead to accumulation of alfentanil. Caution and lower doses of alfentanil are prudent.
• amiodarone (Cordarone) may lead to abnormal heart rhythm.
• anticoagulants may lead to stomach or intestinal bleeding.
• aspirin can result in prolonged bleeding time or hemorrhage.
• beta-blocker medicaments or digitalis preparations may affect heart rate and rhythm. Careful patient monitoring is necessary if these medicaments are combined.
• carbamazepine (Tegretol) may result in toxicity and seizures.
• cilostazol (Pletal) may result in cilostazol toxicity. Lower cilostazol doses are prudent.
• cisapride (Propulsid) may lead to heart toxicity.
• cyclosporine (Sandimmune) may result in cyclosporine toxicity and kidney failure.
• digoxin (Lanoxin) can result in digoxin toxicity.
• dofetilide (Tikosyn) may result in dofetilide toxicity. Checks of dofetilide levels and dosing adjustments to levels are prudent.
• lithium (Lithobid, others) can result in psychosis and neurotoxicity.
• lovastatin (Mevacor), simvastatin (Zocor) may increase these (and perhaps other) HMG CoA reductase inhibitor levels that rely on CYP 450 3A4 for removal, and increase risk of muscle damage. Lower HMG CoA doses, and careful patient monitoring are prudent.
• midazolam (Versed) may result in midazolam toxicity. Lower doses (by 50%) and careful patient monitoring is critical.
• nifedipine (various) may result in nifedipine toxicity. Alternative medicines or nifedipine dosing adjusted to blood levels is prudent.
• nonsteroidal anti-inflammatory medicaments (NSAIDs) may lead to stomach or intestinal bleeding.
• oral anticoagulants (warfarin-Coumadin, others) may result in higher than expected anticoagulation. Increased INRs and careful patient following is prudent.
• oral antidiabetic medicaments  such as glipizide (Glucotrol) may result in greater than expected lowering of blood sugar and hypoglycemia.
• phenytoin (Dilantin) and fosphenytoin (Cerebyx) decreases phenytoin and fosphenytoin metabolism and may cause toxicity. Lower doses and blood level checks are prudent.
• quinidine (Quinaglute, others) may lead to quinidine toxicity.
• rifabutin (Mycobutin) may decrease diltiazem blood levels.
• rifampin (Rifadin) may result in decreased diltiazem effectiveness.
• ritonavir (Norvir) and other protease inhibitors may lead to diltiazem toxicity.
• tacrolimus (Prograf) may result in tacrolimus accumulation and tacrolimus toxicity.
• theophylline (Theo-Dur, others) may lead to theophylline toxicity.
• tretinoin (Vesanoid, others) may lead to tretinoin toxicity.
• triazolam (Halcion) may lead to triazolam toxicity.

The following medicaments may increase the effects of diltiazem:



• cimetidine (Tagamet).
• fluoxetine (Prozac).
• fluvoxamine (Luvox).
• quinupristin/dalfopristin (Synercid).
• ranitidine (Zantac).
• sertraline (Zoloft).

Foods:

May increase absorption and cause a 30% increase in blood levels. Avoid excessive salt intake.

Herbal medicines or minerals:

Ginseng may increase blood pressure, blunting the benefits of this medicine. Hawthorn, saw palmetto, ma huang, goldenseal, yohimbe and licorice may also cause increased blood pressure. Garlic and calcium may work to lower blood pressure. The combination may work to require lower diltiazem doses. St. John's wort may work to lower calcium channel blocker levels (because it increases P-glycoprotein in the gut). This combination may also increase sun sensitivity. Eleuthero root and ma huang should be avoided by people living with hypertension.
Indian snakeroot has a German Commission E monograph indication for hypertension-talk to your doctor. Discuss any plans for herbal medicines or minerals with your doctor.

Alcohol:

Alcohol may exaggerate the drop in blood pressure.

Tobacco smoking:

Nicotine reduces benefits.

Marijuana smoking:

Possible reduced effectiveness of this medicament; mild to moderate increase in angina; possible changes in electrocardiogram, confusing interpretation.

Exposure to sun:

This medicament may cause photosensitivity

Exposure to heat:

Hot environments can exaggerate the blood-pressure-lowering effects of this medicament. Observe for light-headedness or weakness.

Heavy exercise or exertion:

May improve ability to be more active without angina pain. Use caution, and avoid exercise that might be excessive and yet not result in warning pain.

Discontinuation:

Do not stop this medicament abruptly. Ask your doctor about gradual withdrawal.