Indications
Diltiazem Hydrochloride is used to:
- prevent chest pain caused by angina (including angina from spasm of the heart arteries);
- lower high blood pressure (long-acting forms);
- control a fast heart rate in some heart rhythm problems, such as atrial fibrillation (injection given in hospital);
- heal a chronic anal fissure (a painful tear at the back passage), as an ointment prescribed by a doctor.
How It Works
Diltiazem is a calcium channel blocker. It reduces the entry of calcium into the muscle cells of the heart and blood vessels. This widens the arteries, lowers blood pressure, eases the heart’s workload and slows the heart rate. In the ointment form it relaxes the muscle around the anus so the tear can heal.
Dosage and Administration
- Angina, standard tablets, adults: often 60 mg three times a day, increased if needed, as prescribed. Older people and those with liver or kidney problems usually start lower.
- Long-acting (sustained-release) capsules or tablets for angina or blood pressure: once or twice a day, at the strength prescribed. Swallow whole; do not crush or chew.
- Heart rhythm problems: the injection is given by a doctor or nurse in hospital.
- Anal fissure ointment: apply a small amount around the anus, usually twice a day, for the time the doctor advises.
- Children: as prescribed by a specialist.
Different brands of long-acting diltiazem may not work the same way, so keep to the same product unless your doctor changes it. Do not stop suddenly if you take it for angina.
Interactions
Taking it with beta blockers (such as Atenolol or Metoprolol), Digoxin, Amiodarone or Ivabradine can slow the heart too much; Ivabradine must not be combined with it. Diltiazem raises the levels of some statins (Simvastatin, Lovastatin), Cyclosporine, Tacrolimus, Carbamazepine and some sedatives, so doses may need lowering. Rifampicin can make diltiazem much less effective. Other blood pressure medicines add to its effect. Tell your doctor about all medicines you take.
Contraindications
- Allergy to Diltiazem
- A very slow heart rate, sick sinus syndrome, or second or third degree heart block, unless a pacemaker is fitted
- Very low blood pressure or cardiogenic shock
- Heart failure with fluid on the lungs (left ventricular failure)
- Use together with Ivabradine
- Pregnancy and breastfeeding
Side Effects
Common: swollen ankles, headache, flushing, dizziness, tiredness, nausea, constipation and a slow heartbeat. The ointment may cause headache and local itching or burning.
Get medical help at once for: a very slow or irregular pulse, fainting, worsening shortness of breath or swelling, chest pain that is new or worse, yellow skin or eyes, or a severe rash, blisters or peeling skin.
Pregnancy and Lactation
Diltiazem should not be used in pregnancy, as animal studies suggest possible harm to the baby. Women who could become pregnant should use reliable contraception. It passes into breast milk, so it is not used during breastfeeding unless the doctor decides it is essential.
Precautions and Warnings
- Take extra care with heart failure, a slow heart rate, liver or kidney problems, and in older people.
- Your pulse and blood pressure may be checked regularly.
- It can cause dizziness; take care when driving or standing up quickly.
- Avoid large amounts of grapefruit juice.
- Tell your surgeon or anaesthetist that you take diltiazem.
Overdose
An overdose can be dangerous, causing very low blood pressure, a very slow heart rate, heart block, fainting and collapse. Go to hospital immediately, even if you feel well, as long-acting forms can act late.
Therapeutic Class
Calcium channel blocker (non-dihydropyridine); antianginal and antihypertensive medicine.
Storage
Store below 30°C in a dry place, away from light and out of the reach of children.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.