Diltiazem

Common Uses

Diltiazem is primarily prescribed for the following cardiovascular conditions:

• High Blood Pressure (Hypertension): It is used alone or in combination with other medications to lower blood pressure. Managing hypertension helps prevent future health issues such as strokes, heart attacks, and kidney disease.
• Chest Pain (Angina): Diltiazem is used to prevent chronic stable angina and angina caused by coronary artery spasms. It works by increasing the supply of blood and oxygen to the heart while reducing its workload.
• Heart Rhythm Disorders: Specific formulations, including intravenous versions, are used to control the heart rate in patients with certain arrhythmias, such as atrial fibrillation, atrial flutter, and paroxysmal supraventricular tachycardia (PSVT).

Diltiazem is intended for the long-term management and prevention of these conditions. It is not used to provide immediate relief during an active attack of chest pain.

Mechanism of Action

Diltiazem belongs to a class of medications known as calcium channel blockers. It works by affecting the movement of calcium into the cells of the heart and the walls of the blood vessels. Because calcium is necessary for these muscles to contract, blocking its entry allows the muscles to relax.

Effects on the Body

The relaxation of these muscles leads to several key effects on the cardiovascular system:

• Blood Vessel Relaxation: By relaxing the smooth muscles in the blood vessel walls, diltiazem causes the vessels to widen. This process, known as vasodilation, lowers blood pressure and makes it easier for the heart to pump blood throughout the body.
• Increased Oxygen Supply: The widening of the arteries that supply the heart increases the amount of blood and oxygen reaching the heart muscle. This helps reduce the workload on the heart and can prevent chest pain.
• Heart Rate Control: Diltiazem also slows the electrical signals in the heart. This helps to decrease a rapid heart rate and can assist in managing certain types of irregular heart rhythms.

Common Side Effects

Many people using diltiazem do not experience significant side effects. When they do occur, common symptoms may include:

• Dizziness or lightheadedness
• Headache
• Nausea or upset stomach
• Constipation
• Flushing (redness or warmth in the face or neck)
• Tiredness or weakness
• Swelling in the ankles or feet

Serious Side Effects

Contact a healthcare provider immediately if you experience any of the following serious symptoms:

• Slow, fast, or pounding heartbeat
• Fainting or severe lightheadedness
• New or worsening chest pain
• Shortness of breath
• Sudden, unexplained weight gain
• Severe skin reactions, including rash, itching, or blistering skin
• Yellowing of the skin or eyes (jaundice)
• Dark-colored urine

Heart Conditions

Diltiazem can affect the electrical system of the heart. It is generally avoided in people with certain types of heart block or sick sinus syndrome unless a functional pacemaker is in place. It may also worsen symptoms in individuals with congestive heart failure or those who have recently experienced a heart attack with fluid buildup in the lungs.

Blood Pressure and Heart Rate

This medication can cause a significant drop in blood pressure (hypotension) or an abnormally slow heart rate (bradycardia). Healthcare providers typically monitor these vitals regularly during treatment.

Liver and Kidney Function

Because the liver processes diltiazem and the kidneys help remove it from the body, individuals with liver or kidney disease may require closer monitoring or dosage adjustments. Rare cases of severe liver injury have been reported.

Drug Interactions

Diltiazem interacts with several other medications, which may increase the risk of side effects:

• Statins: Using diltiazem with certain cholesterol-lowering drugs like simvastatin can increase the risk of muscle injury. Specific dose limits for simvastatin are often required when taken concurrently.
• Beta-blockers: Combining diltiazem with beta-blockers may lead to an excessively slow heart rate or heart rhythm issues due to additive effects on the heart.

Serious Skin Reactions

Although rare, serious and potentially life-threatening skin reactions have occurred. Immediate medical attention is necessary if a rash, skin peeling, or blisters develop while taking this medication.

Pregnancy

There are no adequate and well-controlled studies regarding the use of diltiazem in pregnant women. In animal studies, high doses of the medication were associated with fetal harm, including skeletal abnormalities and embryo death. Because of the lack of human data, diltiazem is typically only prescribed during pregnancy if a healthcare provider determines that the potential benefit to the mother justifies the potential risk to the fetus.

If you are pregnant or planning to become pregnant, discuss the risks and benefits of this medication with your healthcare team.

Breastfeeding

Diltiazem is excreted into human breast milk. Some reports indicate that the concentration of the drug in breast milk may be similar to the levels found in the mother's blood. Due to the potential for adverse reactions in a nursing infant, a decision should be made whether to discontinue nursing or discontinue the drug, taking into account the importance of the medication to the mother's health.

Consult with a healthcare professional to determine the most appropriate course of action for your situation.

Oral Formulations

Diltiazem is most commonly prescribed as an oral medication. Because different oral products release the drug at different rates, they are often not interchangeable.

• Immediate-release tablets: These are typically taken multiple times per day.
• Extended-release capsules: These are designed to release the medication slowly. Some versions are taken twice daily (12-hour), while others are taken once daily (24-hour).
• Extended-release tablets: These are generally taken once per day.

Injectable Formulations

Diltiazem is also available as an injection or intravenous infusion. This form is typically used in a hospital or clinical setting for the rapid management of certain heart rhythm conditions.

Strengths for oral diltiazem vary significantly based on the specific formulation and the condition being treated, ranging from low-dose tablets to high-dose extended-release capsules. Injectable forms are provided as concentrated solutions for dilution or direct administration.

FDA Approval and Indications

Diltiazem is FDA-approved for several cardiovascular conditions. The specific indications depend on the formulation of the drug:

• Hypertension: Approved for the management of high blood pressure, often using extended-release formulations.
• Angina: Approved for the treatment of chronic stable angina and angina due to coronary artery spasm (Prinzmetal's variant angina).
• Arrhythmias: The intravenous (IV) form is approved for the temporary control of rapid heart rate in patients with atrial fibrillation or atrial flutter, and for the treatment of paroxysmal supraventricular tachycardia (PSVT).

Safety Communications and Labeling Changes

The FDA has issued safety communications regarding significant drug interactions involving diltiazem. A major update involves its use with simvastatin, a cholesterol-lowering medication. Diltiazem can increase the levels of simvastatin in the body, which raises the risk of muscle injury (myopathy) and a severe condition called rhabdomyolysis. Consequently, the FDA recommends that patients taking diltiazem should not exceed a daily dose of 10 mg of simvastatin.

Regulatory Status

Diltiazem is available only by prescription. It is produced in several forms, including immediate-release tablets, extended-release capsules, and injectable solutions for hospital use. There are currently no Boxed Warnings or Risk Evaluation and Mitigation Strategies (REMS) required for diltiazem products. The FDA continues to monitor the safety profile of diltiazem through the Adverse Event Reporting System (FAERS) to identify potential new safety signals.

Risks of Abrupt Discontinuation

You should not stop taking diltiazem suddenly without consulting your doctor. Stopping the medication abruptly can cause your condition to worsen. For individuals taking diltiazem for chest pain, stopping the drug suddenly may lead to a return of chest pain that is more frequent or more severe than before.

Safe Discontinuation

If it is necessary to stop treatment, healthcare providers typically recommend a gradual reduction in dosage rather than stopping all at once. This tapering process allows the body to adjust and helps prevent heart-related symptoms from recurring. Always follow the specific tapering schedule provided by your healthcare professional.

Medical Supervision

Your doctor will determine the best way for you to stop taking this medication based on your individual health needs. Do not skip doses or stop taking the medicine even if you feel well, unless instructed to do so by a medical professional.