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Co-Diovan is a medication that is commonly used to reduce high blood pressure (hypertension). It is a combination of two principal ingredients and is often prescribed when one medicine does not help to control the blood pressure adequately.

What is Co-Diovan?

Co-Diovan is made up of valsartan and hydrochlorothiazide. Valsartan is a medicine that treats high blood pressure and heart failure and is also sometimes given after a heart attack. It is also known by its brand name, Diovan. Valsartan is an ARB (angiotensin-2 receptor blocker) which works to relax and dilate the blood vessels, so the blood pressure drops and the heart can pump the blood around the body more easily.

Hydrochlorothiazide contains ingredients that cause more frequent urination than usual. It is also used to reduce high blood pressure as urinating often gets rid of the excess salt and water in the body and allows the heart to pump blood more freely. Hydrochlorothiazide is part of a group of medicines commonly known as thiazides. These are diuretics – sometimes referred to as water tablets because they flush excess water and salt out of the body by working on the kidneys. If there is too much salt in your body, it can cause the fluid to increase in your blood vessels and raise your blood pressure.

Co-Diovan is often prescribed when valsartan has worked successfully on its own. In some cases, increasing the dose of Valsartan does not reduce blood pressure, so Co-Diovan is an alternative that a doctor may prescribe.

There are many medicines to reduce high blood pressure, and Co-Diovan is only one of them. Your doctor will decide which is most suitable for you. If you have high blood pressure, you may be prescribed a combination of medicines to help reduce it as different types of medication can help adjust your blood pressure in different ways.

The combination of valsartan and hydrochlorothiazide make up the medication Co-Diovan, with a higher percentage of valsartan. There are different strengths of Co-Diovan available, and you should always take the dosage prescribed by your doctor. Never take more than the prescribed dose to try and lower your blood pressure yourself, without talking to your doctor.

When is Co-Diovan used?

Co-Diovan is used to control high blood pressure (hypertension). It is often used when a single medication, such as valsartan on its own, does not work well enough. High blood pressure is a common condition experienced by many people. You may not realise immediately that you have high blood pressure unless you are tested. However, it can cause serious medical problems such as a heart attack, stroke, kidney disease or damage to other organs, so it is important to treat this condition.

High blood pressure can occur in people who:

  • Are obese or overweight;
  • Smoke;
  • Have a history of high blood pressure in their family;
  • Suffer from any medical condition that affects your heart;
  • Have high cholesterol;
  • Have diabetes;
  • Suffer from kidney disease;
  • Drink excessive alcohol;
  • Use the oral contraceptive pill;
  • Take NSAIDs (non-steroidal anti-inflammatory drugs);
  • Suffer from stress or anxiety;
  • Take antidepressants.

You therefore should have your blood pressure checked regularly to monitor it, otherwise you may not know you have high blood pressure until something serious such as a heart attack occurs.

When a person suffers from high blood pressure, blood vessels can be damaged by the pressure in the arteries – the tubes inside the body that carry the blood away from the heart. As the heart beats, it pumps the blood around the body through the arteries. The blood supplies the various organs in the body to ensure they are healthy and working well.

High blood pressure (and unhealthy living) however can cause hardening of the arteries, which means they can become blocked or lined with a plaque that reduces the correct flow of the blood. These can lead to a heart attack or other serious and/or fatal illness.

If you have high blood pressure, your doctor will take into account your circumstances and may prescribe you a medication such as Co-Diovan tablets to help reduce it. If you are prescribed Co-Diovan tablets or any other blood pressure-lowering medication (you can take more than one on medical advice), your doctor will also advise you to follow a healthy lifestyle.

Medication can treat the symptoms, but a healthy lifestyle can greatly improve your condition. This includes eating a healthy diet; doing regular exercise, giving up smoking and reducing your alcohol intake.

How do you use Co-Diovan?

The usual dose is one Co-Diovan tablet each day in the morning. Always follow the dose that has been prescribed by your doctor exactly. Your doctor will monitor your renal function with blood tests when starting the medication. You should take your Co-Diovan tablet at the same time each day with or without food. Take the Co-Diovan tablet with a glass of water and do not chew it. If you forget to take your Co-Diovan tablet, you should not take another until the next one is due. You should never take a double dose as this could be dangerous.

Because this medication can make you urinate more often, is it not advisable to take it immediately before you go to bed or you are likely to have to get up in the night. You should take your Co-Diovan tablet a minimum of four hours before you go to bed to avoid this. You should not stop taking this medication without consulting a doctor, as this could cause an increase in your blood pressure. Once you are prescribed medication to lower your blood pressure, you will likely have to take it long- term. It is also important to visit your doctor regularly to have your blood pressure monitored and decide if your medication or dosage needs to be changed. You can buy blood-pressure monitoring machines for use at home, which are useful to monitor your blood pressure regularly. You can then show the doctor the readings over a period of time, for example, a month or three months. Most major chemists also offer a free blood pressure monitoring service.

What dosages are there?

There are three different strengths of Co-Diovan tablet, namely 80 mg/12.5 mg, 160 mg/12.5 mg and 160 mg/25 mg. Your doctor will decide which is the most appropriate dose for you.

What are the side effects of Co-Diovan?

When you first take Co-Diovan tablets, you may experience some side effects, the most common ones being:

  • Headache;
  • Dizziness / lightheadedness;
  • Tiredness;
  • Coughing;
  • Flu symptoms;
  • Diarrhoea;
  • Cold symptoms;
  • Blurred vision;
  • Ringing in the ears;
  • Tingling sensation.

The side effects will usually only be mild or last a short time. This occurs while your body is getting used to the medication. Side effects can also occur if you are prescribed a different dose by your doctor. If you are concerned about the side effects when taking Co-Diovan tablets, you should talk to your doctor.

When should you not use Co-Diovan?

You should not take Co-Diovan tablets if you are allergic to any of the ingredients listed on the package leaflet. You should also not take Co-Diovan tablets if you take medication that reduces or increases the amount of potassium in your blood, if you take lithium (sometimes used to treat psychiatric diseases), other medication to lower your blood pressure, or take or have been prescribed certain antibiotics.

These are only some of the reasons not to take Co-Diovan tablets. You must talk to your doctor about any medication you are taking and any condition you have before taking Co-Diovan tablets. There is also a list of other medicines not to take with Co-Diovan on the package information leaflet. You should not take Co-Diovan tablets if you are pregnant, planning to become pregnant in the future or breastfeeding. Co-Diovan tablets may be harmful to an unborn child. You may not be able to take it if you have severe heart, liver or kidney problems. If you suffer from side effects such as dizziness or headaches that could affect driving or the operation of machinery, you should not carry out these activities. It is not advisable to drink alcohol during your treatment with Co-Diovan as this could make your blood pressure to drop dramatically and make you feel faint or dizzy.

Does Co-Diovan interact with other medications?

As with all medicines, Co-Diovan tablets may interact with other medication you are taking. Therefore, it is important to inform your doctor about any medicines you are taking before you start to take Co-Diovan tablets, including herbal medicines.

Where can you buy Co-Diovan?

Co-Diovan tablets can only be prescribed by a doctor. You cannot buy it over the counter in a pharmacy.

Can I get Co-Diovan without a prescription?

No, you cannot get Co-Diovan tablets without a prescription.


Blood Pressure UK. (n.d.). Retrieved 12 March 2020 from

Fogoros, R.N. (2019, November 26.) What is Hypertension (High Blood Pressure)? Retrieved 12 March 2020 from

NPS MedicineWise. (2009, March 10). Valsartan (Diovan) and combinations with hydrochlorothiazide (Co-Diovan) or amlodipine (Exforge). Retrieved 12 March 2020 from combinations-with-hydrochlorothiazide-co-diovan-or-amlodipine-exforge

Valsartan. (2018, December 13). Retrieved 12 March 2020 from

Reviewed by:

Dr Imran Malik, General practitioner Registrationnumber: GMC: 4741365 Last checked: 23-08-2023 | Still valid

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