Drug information of cyclopenthiazide


Cyclopenthiazide belongs to a group of medicines called thiazide diuretics. A diuretic is a medicine which increases the amount of urine that you pass out from your kidneys. They are often referred to as 'water tablets'. Diuretics are a common treatment for high blood pressure (hypertension). They are also used to clear excess fluid from your body in conditions where your body retains more than it needs. This is called oedema. Cyclopenthiazide is also useful in people who have heart failure. Heart failure is a condition where your heart is not functioning as well as it should.
Diuretics like cyclopenthiazide work by interfering with the transport of salt and water across certain cells in your kidneys. The effect of this is to make your kidneys pass out more urine. The removal of fluid reduces your blood pressure and helps reduce the work your heart has to do.
Cyclopenthiazide is usually given alongside other diuretics to treat high blood pressure. When it is used like this, you may be prescribed a combination tablet, such as Navispare®. This brand contains cyclopenthiazide with amiloride. Combination tablets like this help to reduce the number of tablets you need to take each day.

Mechanism of effect

Cyclopenthiazide is a benzothiadiazine (thiazide) diuretic. Cyclopenthiazide is a thiazide diuretic which exerts diuretic effect by inhibiting the reabsorption of sodium chloride and water probably at the distal renal tubules.

Drug indications

High blood pressure (hypertension).
    Mild to moderate stable, chronic heart failure.
    Excess fluid retention (oedema) due to kidney disease.
    Excess fluid collection in the abdomen (ascites) due to cirrhosis of the liver.
    Excess fluid retention (oedema) in pre-menstrual syndrome.

Drug contraindications

Children , pregnancy , Breast feeding , Hypocalcemia , Addisons disease , Severe Renal Impairment

People allergic to thiazide diuretics.
    People allergic to medicines from the sulphonamide group, eg the antibiotic sulfamethoxazole.
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.


It should be used with caution in patients with a history of hypersensitivity thiazide or related diuretics or sulfonamide and in patients with hepatic disease.
 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.
    Alcohol may enhance the blood pressure lowering effect of this medicine, which could cause dizziness or fainting. Take extra care if you drink alcohol while you are taking this medicine.
    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.
    Cyclopenthiazide can sometimes cause the level of sodium in your blood to fall too low and, for this reason, following a very strict low salt (sodium) diet should be avoided while you are taking this medicine.

Points of recommendation

Use with caution in:
  • Elderly people.
  • Kidney disease.
  • Liver disease.
  • Diabetes.
  • 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).
  • A condition called systemic lupus erythematosus, which involves long-term inflammation of some internal organs.
  • People on a low salt (sodium) diet.
  • People who are malnourished.

Pregnancy level

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. The expected benefit to the mother must be greater than the possible risks to the developing baby. .

Breast feeding warning

Cyclopenthiazide passes into breast milk and could have unwanted effects on a nursing infant. In high doses it can also reduce the production of breast milk. This medicine is not recommended for women who are breastfeeding.

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