1. Overview

• Generic name: Diltiazem HCl
• Brand name: Cardizem
• Drug class: Calcium channel blockers

Diltiazem is a Calcium Channel Blocker that is used to treat high blood pressure, angina (chest pain) and several other conditions.

It's a prescription medicine and is available as tablets, capsules, ointments or creams (topical dosage form).

Diltiazem works by relaxing the coronary arteries, increasing the delivery of oxygen to heart and decreasing heart rate.

2. Uses

Diltiazem is used to treat:

1. High blood pressure
2. Chest pain (Angina)
3. Chronic Anal fissures (either by using creams or tablets)
4. Arrythmias
5. Diltiazem is also used to temporarily Control Rapid Ventricular Rate in Atrial Fibrillation/Flutter

3. Dosage forms

Diltiazem is available as:

Diltiazem ER:

1. Solution for Injection: 25 mg/5 ml, 50 mg/10 ml, 125 mg/25 ml.
2. Immediate-Release Tablets: 30 mg, 60 mg, 90 mg, 120 mg.
3. Extended-Release Capsules, (24 Hour): 120 mg, 180 mg, 240mg, 300 mg, 360 mg, 420 mg.
4. Extended-Release Capsules, (12 Hour): 60 mg, 90 mg, 120 mg.
5. Extended-Release Tablets, (24 Hour): 120mg, 180 mg, 240 mg, 300 mg, 360 mg, 420 mg.

Note: Different brands of extended-release (ER) diltiazem may not contain the same dose. Your medication is prescribed for your specific needs; hence it’s recommended to take your own brand without changing it.

4. How & when to take Diltiazem

For Capsules and tablets
Only Immediate-release tablets can be crushed; Immediate-release dosage forms should be taken before meals and at bedtime.

Sustained release capsules or tablets should not be broken, crushed, divided or dissolved.

Extended-release capsules or tablets should not be broken, crushed, divided or dissolved.

Some formulations such as (Cardizem CD, Cardizem LA and Cartia XT) may be taken without considering meals.

Can I stop taking the drug if I feel better?
Do not stop taking Diltiazem without talking to your doctor. If you stop suddenly the symptoms might reappear, and it may worsen angina.

What should I do If I missed a dose?
Take the missed dose as soon as you remember, however, if you are supposed to take your next dose within 2 hours, take one dose now and skip the next dose.

5. Special precautions

Be sure to tell your doctor if:

• You have long-term liver or kidney problems.
• You have heart failure.
• You are taking other medicines such as beta blockers.
• You have hypertrophic obstructive cardiomyopathy.
• You have sensitivity to Diltiazem.

Pregnancy and breastfeeding:
Diltiazem is not usually prescribed during pregnancy, it’s best to discuss the matter with your doctor. Diltiazem might affect breastfed babies since the drug passes into the milk. Discussing with your doctor is necessary.

Can I drive and do hazardous work while I’m using Diltiazem?
Diltiazem causes dizziness since the drug can lower blood pressure; therefore, it’s recommended to avoid those activities until you have found out how diltiazem affects you.

Can I drink Alcohol while using diltiazem?
Avoid drinking too much. Alcohol may cause dizziness by lowering blood pressure.

6. Who cannot use Diltiazem?

Diltiazem is not suitable for certain individuals who:

• Have diseases such as Acute Myocardial Infarction MI, pulmonary congestion
• Are hypersensitive to Diltiazem
• Have severe hypotension (systolic less than 90 mm Hg)
• Have second- or third-degree AV block (also called heart block). Exception: when pacemaker is present.
• Are suffering from sick sinus syndrome without the presence of a pacemaker, (if pacemaker is present Diltiazem could be used)

Diltiazem is also not recommended for infants and children.

7. Side effects

The frequency of these side effects is between 2% to 10% in Diltiazem users. The most common side effects of the drug are:

• Swelling of lower legs and/or hands
• Dizziness
• Light-headedness
• Fatigue and weakness
• Headache
• Constipation
• Cardiac conduction disorders
• Bradycardia
• GIT or abdominal discomfort
• Nausea
• Flushing

On rare occasions, you might have a severe anaphylaxis reaction (allergic reaction) to this medication; If this occurs, you should seek immediate medical attention and stop taking diltiazem immediately.

Read Diltiazem side effects in detail.

8. Interactions

Several drugs and other substances can interact with diltiazem resulting in undesired effects.
Interaction can affect activity of the drug or increase the likelihood and severity of side effects.

Interactions with drugs
Diltiazem can form drug-drug interactions with the following drugs:

• Beta blockers (e.g., carvedilol, metoprolol, labetalol)
• Digoxin
• Carbamazepine, benzodiazepines
• Rifampin
• Statins (e.g., Simvastatin)
• Anticonvulsant drugs
• Anti-arrhythmic drugs
• Theophylline/aminophylline
• Antihypertensive drugs

Interactions with Herbal medicine:
Ginseng, yohimbe and Ephedra might make hypertension worse, Ephedra might lead to worsened arrythmias as well.
Concentration of diltiazem might be decreased by St. John’s wort.
Garlic has a role in increasing antihypertensive effect.

Food interaction:To the present day no Food-Diltiazem interaction has been reported.