Kalspare (Triamterene, chlortalidone)
How does it work?
Kalspare tablets contain two active ingredients: triamterene, which is a type of medicine called a potassium-sparing diuretic and chlortalidone, which is a type of medicine called a thiazide-related diuretic.
Diuretics act in the kidneys. They work by causing the kidneys to increase the amount of salts, such as potassium and sodium, that are filtered out of the blood and into the urine. When these salts are filtered out of the blood by the kidneys, they draw water alongside them. As diuretics increase the removal of salts from the blood, they also cause more water to be drawn out of the blood and into the urine.
Removing water from the blood decreases the volume of fluid circulating through the blood vessels. This subsequently decreases the pressure within the blood vessels. Diuretics such as chlortalidone and triamterene can therefore be used to lower high blood pressure.
Diuretics are also used to treat conditions where excess fluid has been retained in the body (oedema). For example, in heart failure, the pumping mechanism of the heart is less effective. This can cause fluid to build up in the ankles and the lungs (pulmonary oedema), which makes it difficult to breathe. Diuretics help the body to remove this excess fluid. Removing fluid from the blood vessels also decreases the pressure within the blood vessels. This makes it easier for a weak heart to pump blood around the body.
This medicine can also be used to remove excess fluid that accumulates in the body in people taking corticosteroid medicines and in people with kidney disease or cirrhosis of the liver. In liver cirrhosis this fluid may accumulate in the abdomen (ascites) or in the legs (oedema).
Chlortalidone can cause lots of potassium to be filtered out of the blood, which can sometimes cause the level of potassium in the blood to fall too low. A low blood potassium level is called hypokalaemia and can sometimes be dangerous, particularly for people with heart disease or liver disease.
Triamterene on the other hand, is a weaker diuretic that causes potassium to be retained in the body. It is used in combination with the chlortalidone in this medicine to prevent the amount of potassium in the blood from falling too low.
What is it used for?
- Mild to moderate high blood pressure (hypertension).
- Heart failure.
- Fluid retention (ascites and oedema) in liver cirrhosis.
- Excess fluid retention due to kidney disease (nephrotic syndrome).
- Excess fluid retention (oedema) due to treatment with corticosteroid medicines such as prednisolone or dexamethasone.
How do I take it?
- Kalspare tablets should be swallowed with a drink of water with or after breakfast.
- The number of tablets to be taken daily will vary depending on the condition being treated. Follow the instructions given by your doctor. These will be printed on the dispensing label that your pharmacist has put on the medicine.
- As diuretics cause your kidneys to produce more urine, you may find that if you take a dose too late in the day that you need to get up in the night to visit the toilet. This is why it is recommended that you take this medicine in the morning. Seek further advice from your doctor or pharmacist.
- This medicine may cause fatigue and dizziness. You should take care when performing potentially hazardous activities, such as driving or operating machinery, until you know how this medicine affects you and are sure you can perform such activities safely.
- If you do feel dizzy while you are taking this medicine you should take extra care if you drink alcohol, as this may make any dizziness worse.
- While taking this medicine you may need to have regular blood tests to monitor your kidney function and the levels of salts such as potassium and sodium in your blood.
- If you experience any of the following symptoms while taking this medicine you should inform your doctor promptly, so that the amount of fluids and salts in your body can be checked: thirst, lethargy, confusion, weakness, drowsiness, muscle cramps, scanty production of urine, abnormal heart rhythm, seizures, nausea and vomiting.
- This medicine can cause the amount of potassium in your bloodstream to increase. For this reason you should avoid consuming large amounts of foods that have a high potassium content, for example dried fruit, bananas, tomatoes and 'low sodium' salt, while you are taking the medicine. You should also avoid potassium supplements.
- If you need a test to assess the functioning of your parathyroid gland your doctor may ask you to stop taking this medicine beforehand, as it may interfere with the test results.
- This medicine can turn your urine a blue colour, which is only noticeable in certain light. This is normal and nothing to worry about - it is due to the colour of the medicine.
Use with caution in
- Elderly people.
- Decreased liver function.
- Decreased kidney function.
- People with a history of high levels of uric acid in their blood or gout.
- People with high levels of fats (lipids) such as cholesterol and triglycerides in the blood (hyperlipidaemia).
- An inflammatory disease of connective tissue (systemic lupus erythematosus).
Not to be used in
- Severe liver disease.
- Kidney failure.
- People whose kidneys are not producing urine.
- People allergic to medicines from the sulphonamide group, eg the antibiotic sulfamethoxazole.
- People with a high level of potassium in their blood (hyperkalaemia).
- People with a high level of calcium in their blood (hypercalcaemia).
- Diabetic acidosis.
- People with inadequate production of natural steroid hormones by the adrenal glands (Addison's disease).
- Children or adolescents under 18 years of age.
This medicine should not be used if you are allergic to any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.
If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.
Pregnancy and breastfeeding
Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.
- This medicine should not normally be used during pregnancy. Thiazide diuretics can reduce placental blood flow to the baby and, if used in the second or third trimester, can cause problems such as jaundice, low platelet count and disturbances in the baby's electrolyte levels. This medicine should not be used to treat high blood pressure in pregnancy or fluid retention in otherwise healthy pregnant women. It should only be used in other situations if considered essential by your doctor. The expected benefit to the mother must be greater than the possible risks to the developing baby. Seek further medical advice from your doctor.
- This medicine passes into breast milk and could have unwanted effects on a nursing infant. It should not be used in women who are breastfeeding. Seek further medical advice from your doctor.
- Take this medication with or after food.
- This medication may cause your urine to be coloured.
Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Just because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.
- Disturbances of the gut such as diarrhoea, constipation, nausea, vomiting or abdominal pain.
- Muscle cramps.
- Feeling weak.
- Dry mouth.
- Feeling thirsty.
- Low blood pressure.
- Abnormal reaction of the skin to light, usually a rash (photosensitivity).
- Increased level of uric acid in the blood (hyperuricaemia) - this may cause kidney problems and gout.
- Increased blood sugar level (hyperglycaemia).
- Rise in the levels of fats such as cholesterol in the blood.
- Increased level of calcium in the blood (hypercalcaemia).
- Disturbances in the normal numbers of blood cells in the blood.
The side effects listed above may not include all of the side effects reported by the medicine's manufacturer.
For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.
How can this medicine affect other medicines?
It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to make sure that the combination is safe.
This medicine is likely to have an additive effect with other medicines that decrease blood pressure, particularly medicines that are used to treat high blood pressure (antihypertensives). This may cause dizziness, which can usually be relieved by lying down until the symptoms pass. If you feel dizzy while taking this medicine in combination with other medicines that can lower blood pressure you should let your doctor know, as your doses may need adjusting. Other medicines that decrease blood pressure include the following:
- ACE inhibitors, eg enalapril
- alpha-blockers such as prazosin
- angiotensin II receptor antagonists such as losartan
- antipsychotics such as chlorpromazine
- benzodiazepines, eg temazepam, diazepam
- beta-blockers such as propranolol
- calcium-channel blockers such as verapamil, nifedipine
- other diuretics, eg furosemide
- dopamine agonists, eg bromocriptine, apomorphine
- MAOI antidepressants, eg phenelzine
- nitrates, eg glyceryl trinitrate
Triamterene may increase the level of potassium in your blood. If this medicine is taken with other medicines that can increase blood potassium levels, this effect may be enhanced. Your doctor may want to monitor your blood potassium levels if you take any of these medicines in combination with Kalspare tablets:
- ACE inhibitors, eg enalapril
- angiotensin II receptor antagonists, eg losartan
- non-steroidal anti-inflammatory drugs (NSAIDs), eg indometacin, diclofenac, ibuprofen
- potassium-containing salt substitutes such as Lo-Salt
- potassium salts, eg potassium citrate for cystitis
- other potassium-sparing diuretics eg spironolactone, triamterene (these should not usually be taken in combination with Kalspare)
- potassium supplements (these should not usually be taken in combination with Kalspare)
Chlortalidone can decrease the amount of potassium in the blood. If Kalspare is used in combination with any of the following medicines, which can also lower potassium in the blood, the risk of a low blood potassium level (hypokalaemia) is increased:
- corticosteroids, such as hydrocortisone and prednisolone
- beta 2 agonists, eg salbutamol, terbutaline
- other diuretics, eg furosemide
- excessive use of stimulant laxatives such as senna
If the level of potassium in your blood falls during treatment, this can increase the risk of side effects on the heart from various other medicines, including digoxin, certain antipsychotics and medicines for abnormal heart rhythms (anti-arrhythmics), eg amiodarone.
Chlortalidone can increase the amount of calcium in your blood. If you are taking calcium or vitamin D supplements, or regularly take large amounts of calcium-containing antacids, your doctor may want to monitor the level of calcium in your blood. Taking occasional antacids should not cause any problems.
Colestyramine and colestipol can reduce the absorption of chlortalidone from the gut. If you have been prescribed either of these medicines you should not take them within two hours of taking Kalspare.
Diuretics reduce the ability of the body to remove the medicine lithium, which can cause the level of lithium in the blood to rise too high. If you are taking lithium your lithium level should be checked after you start and stop treatment with this medicine, as well as after any dose changes. Your lithium dose may need adjusting.
Diuretics can sometimes increase blood glucose levels and people with diabetes may therefore need increases in their dose of insulin or antidiabetic tablets while taking this medicine. If you have diabetes you should talk to your doctor about this. You may need to monitor your blood sugar levels more frequently.
There may be an increased risk of allergic reactions to allopurinol in people taking thiazide-related diuretics such as chlortalidone, particularly if they also have any kidney problems.
The following medicines may reduce the diuretic and blood pressure lowering effect of this medicine:
- corticosteroids, such as dexamethasone or prednisolone
- oestrogens, such as those in the contraceptive pill
- regular use of non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, diclofenac or indomethacin (occasional painkilling doses are unlikely to have a significant effect). Diuretics such as this one also increase the chance of side effects on the kidneys that can be caused by NSAIDs.
Other medicines containing the same active ingredients
There are currently no other medicines available in the UK that contain both triamterene and chlortalidone as the active ingredients.