Tiazac (Diltiazem) for Chronic Stable Angina

Tiazac (diltiazem) is a prescription medication approved by the U.S. Food and Drug Administration (FDA) to treat adults with chronic stable angina, a type of ongoing chest pain.

How Tiazac Works and How It’s Taken

Tiazac is a calcium channel blocker. It limits calcium from entering certain muscle cells in the heart and blood vessels. For people with angina, it may lower the heart’s need for oxygen and help widen the arteries that bring blood to the heart. This can help reduce angina attacks and improve exercise tolerance.

Doctors prescribe Tiazac to treat chronic stable angina.

Tiazac comes as an extended-release capsule taken by mouth once daily. It can be taken with or without food.

The capsule may also be opened and the contents sprinkled on a spoonful of applesauce. Swallow the mixture right away without chewing, then drink a glass of cool water. The applesauce should not be hot. Do not save the mixture for later, and do not divide the capsule contents.

The dose is adjusted based on how the person responds.

Typical Dosing for Chronic Stable Angina

The usual starting dose of Tiazac is 120 milligrams to 180 milligrams once daily. Some people may respond to higher doses, up to 540 milligrams once daily.

When needed, the dose may be adjusted over seven to 14 days.

This information is based on the prescribing information, but your healthcare provider may tailor your treatment plan. Always follow their guidance.

Tiazac Side Effects

In clinical studies of Tiazac for chronic stable angina, the most common side effects occurred in about 2 percent to 10 percent of people. These include:

Headache
Peripheral edema (swelling in the arms, legs, hands, or feet)
Pain
Dizziness
Dyspepsia (upset stomach or indigestion)

Serious Side Effects and Warnings

Tiazac can cause serious side effects that may require immediate medical attention. These include:

Heart rhythm and conduction problems — An abnormally slow heart rate, or second- or third-degree AV block, can cause fainting or severe dizziness.
Worsening congestive heart failure — Fluid buildup and reduced heart pumping in people who already have heart function problems can occur.
Low blood pressure — Hypotension may cause lightheadedness or fainting.
Acute liver injury — Liver damage can happen early in treatment and may show up as abnormal liver tests.

Get medical help right away if you think you are having a serious reaction.

What To Know Before Taking Tiazac

Tell your doctor if you have any allergies to diltiazem or any ingredients in Tiazac.

Tell your doctor about all medicines you take, including prescription drugs, over-the-counter medicines, vitamins, and herbal supplements.

Do not take Tiazac if you have:

Sick sinus syndrome, unless you have a working ventricular pacemaker
Second- or third-degree AV block, unless you have a working ventricular pacemaker
Severe low blood pressure, with a systolic pressure below 90 mm Hg
An allergy to diltiazem
An acute heart attack with fluid buildup in the lungs seen on an x-ray when you are admitted to the hospital

Tiazac is also FDA-approved to treat hypertension (high blood pressure) in adults.

If you are pregnant, planning to become pregnant, or breastfeeding while taking Tiazac, talk with your doctor about the risks and benefits.

Diltiazem passes into human milk; do not breastfeed when taking Tiazac.

Community FAQs

These answers are fact-checked by our editorial staff.

How effective is Tiazac for chronic stable angina?

In a study of people with chronic stable angina, Tiazac improved exercise tolerance.

At 24 hours after a dose, exercise time increased from baseline by 26 to 41 seconds with daily doses of 120 milligrams to 360 milligrams. Exercise time increased by 14 seconds with placebo.

At eight hours after a dose, exercise time increased from baseline by 38 to 64 seconds with daily doses of 120 milligrams to 360 milligrams. Exercise time increased by 13 seconds with placebo.

People taking Tiazac also had fewer angina attacks and used less nitroglycerin than people taking placebo.

How long does Tiazac take to work for chronic stable angina?

The study measured exercise benefits at eight hours and 24 hours after a dose. However, the study result does not state one exact time when every person will notice improvement.

What tests or monitoring are needed with Tiazac for chronic stable angina?

Tiazac can affect heart rhythm and blood pressure. Your healthcare provider may watch for a slow heart rate, atrioventricular block, or low blood pressure.

During long-term treatment, kidney and liver function should be checked at regular intervals. Mild increases in liver enzymes have been reported. Rare cases of sudden liver injury tended to occur within one to eight weeks after treatment started.

In two short-term studies of people with high blood pressure, Tiazac caused a small, dose-related increase in the PR interval, which is part of the heart’s electrical cycle. No cases greater than first-degree atrioventricular block were seen in those clinical studies.