Diltiazem is used on its own or together with other medicines to treat angina (chest pain caused by reduction of oxygen to the heart muscle) and helps to keep your blood pressure under control.
Diltiazem relaxes your blood vessels, and this helps to lower your blood pressure.
Take Diltiazem exactly as directed by your doctor or according to the instructions on the label. Do not take more or less than instructed by your doctor.
Ask your doctor or pharmacist about whether you should take Diltiazem with or without food. Different brands of this medicine may be taken differently. Try to take it at the same time each day.
If you are taking the extended-release of tablet or capsule (usually labelled as "LA", "MR", "SR", "CD", "XL" or "Retard"), swallow it whole. Do not divide, chew or crush the tablet or capsule.
Diltiazem must be taken regularly for it to be effective. Continue taking this medicine even when you feel better. Do not stop taking it unless instructed by the doctor.
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and return to your normal schedule.
DO NOT double a dose under any circumstances.
If you often forget to take your medicine, let your doctor and pharmacist know.
Alert your doctor if you have the following conditions:
- heart rhythm disorder and not using a pacemaker e.g. sick sinus syndrome, second or third degree heart block
- recent heart attack and have a build-up of fluid in your lungs
- slow heart rate or irregular heart beat
- low blood pressure
as Diltiazem may not be suitable for you.
Do not breastfeed while you are being treated with this medicine.
Do not take Diltiazem with ivabradine (medicine used for heart failure) and rifampin (medicine to treat TB).
Inform your doctor if you have the following conditions:
- risk of bowel blockage
- first degree heart block
- kidney disease
- liver disease
Let your doctor know if you are pregnant.
Be sure to check with your doctor or pharmacist before giving this medicine to an elderly. Elderly may be more sensitive to the side effects.
With the extended-release type of Diltiazem, you may see a small tablet-shaped casing in your bowel. This is normal, do not be alarmed. This casing is just an empty shell; the medicine inside it has already been absorbed by your body.
If you are going for a procedure involving ionic contrast agents or an operation, including minor surgery and dental work, inform your doctor or dentist that you are taking this medicine.
Why is it important to keep my appointments with the doctor?
Keep your appointments with your doctor. Your doctor needs to monitor your condition and check your response to the medication regularly.
- Routine tests (e.g. liver/kidney function, heart rate, ECG or test to record the electrical activity of the heart) may be done while you are being treated with this medicine.
- Your blood pressure may fall to unsafe levels without you noticing it. Monitor your blood pressure during treatment.
- Regular monitoring of signs and symptoms of lung disease may also be needed.
Your doctor will advise you about how often you will need to have these tests.
What lifestyle changes can I make to improve my blood pressure?
Regular exercise and eating a healthy diet will help control your blood pressure and improve your overall health. Engage in physical activity like walking for at least 30 to 60 minutes on most days of the week. If you have not exercised for a long time, start with light exercises such as slow walks. Speak to your doctor about what type of exercise would be suitable for you. Follow a healthy diet plan by eating more fruits, vegetables, whole grains and low-fat dairy products and reduce your intake of foods high in saturated fat, cholesterol and sodium. Cutting down on deep-fried foods and using less salt when cooking can kick-start your healthy diet.
If you smoke, you should try to quit. Smoking is harmful to your blood pressure, heart and overall health. Speak to your doctor or pharmacist about ways to stop your smoking habit.
Diltiazem may cause dizziness or restlessness. If affected, do not drive or take part in any activity in which you need to be alert.
Other side effects include any of the following: headache, nausea, weakness, constipation, indigestion, stomach pain, tiredness, redness of the face or skin, and swelling in the ankles, feet or legs.
Some side effects may need immediate medical help. Alert your doctor quickly if you experience any of the following:
- unusually slow, fast or irregular heartbeat, chest discomfort, lightheadedness
- fainting, blurred vision, clammy skin
- pain and tightness of the chest and back, difficulty breathing, wheezing or whistling sound when inhaling, coughing
- changes in mood
- yellowing of the skin or eyes, abdominal pain, dark coloured urine, tiredness, swelling in the legs and ankles
- rashes with peeling of the skin or blistering of the lips, mouth or eyes accompanied by fever
Inform your doctor if any of these side effects do not go away or are severe, or if you experience other side effects.
Do not take Diltiazem with the following medicines:
- ivabradine (medicine for heart failure)
- rifampin (medicine to treat TB)
Inform your doctor and pharmacist if you are taking any of these medicines:
- other medicines for high blood pressure or heart disease e.g. propranolol, digoxin, amiodarone, clonidine
- water pill or medicine for water retention e.g. bendroflumethiazide
- cholesterol-lowering medicine e.g. simvastatin, atorvastatin
- medicine for epilepsy (fits or seizure) e.g. carbamazepine, phenytoin
- medicine that can cause drowsiness or affect your concentration e.g. midazolam, triazolam
- medicine to treat enlarged prostate e.g. terazosin
- anti-inflammatory medicines e.g. methylprednisolone
- blood-thinning medicines e.g. cilostazol
- medicine to block pain and sensation e.g. propofol
- asthma medicine e.g. theophylline
- medicine used in organ transplant or certain immune disorders e.g. ciclosporin, sirolimus, tacrolimus
- muscle relaxant e.g. dantrolene
- gastric medicine e.g. cimetidine, ranitidine
- medicine to treat TB, lung infection known as tuberculosis e.g. rifampicin
- medicine for anxiety e.g. buspirone
- herbal medicine e.g. St. John’s wort
This list does not include all medicines that may interact with Diltiazem.
Always notify your doctor and pharmacist if you are taking any other medicines, including herbal tonics such as traditional Chinese medicines, supplements and medicines that you buy without a prescription.
Avoid alcohol. Avoid excessive consumption of grapefruit or grapefruit juice (more than 1 litre a day).
Store in a cool, dry place away from the reach of children.
Medicines must not be used past the expiry date.