Candesartan is a drug that works by stopping the angiotensin II hormone from activating a receptor in the body that normally leads to a slight increase in blood pressure. When you take a sartan drug, the angiotensin hormone can’t work as well as usual and your blood pressure gets lower, which is useful to treat hypertension and heart failure.
Brand Names and Doses
Candesartan is the genic name, the name of the active drug found in the medication, but it is also known by the brand name: Atacand.
There are four different doses: 4 mg, 8 mg, 16 mg and 32 mg. You will probably start taking a low dose of 4 mg, to reduce the risk of side effects as your body gets used to the new medication. You can then gradually increase the dose as needed to manage blood pressure.
Candesartan is also available in combination with another drug, hydrochlorothiazide. The brand name for this combination is Atacand Plus and there are three different doses available: 16mg candesartan/12.5mg hydrochlorothiazide, 32mg candesartan/12.5mg hydrochlorothiazide and 32mg candesartan/25mg hydrochlorothiazide.
What type of drug is it?
Candesartan is a type of drug called a sartan, which is a class of drugs that work in a similar way. Sometimes sartans are also known by other names, such as angiotensin receptor blockers (ARB) or angiotensin receptor antagonists (ARA). Other medicines in the same class are:
How does it work?
Candesartan works by stopping a hormone called the angiotensin II from attaching to a receptor and having certain effects to increase the blood pressure in the body.
In a healthy person, angiotensin II helps to keep the balance of blood pressure just right. If the blood pressure gets too low, the body releases more angiotensin II and, when it activates the receptor, the effect cause an increase the pressure again. The muscles around the blood vessels contract to make the passageway narrower and the kidneys reabsorb more water to increase the amount of blood in the body. With more blood travelling through narrower passageways, the blood pressure is going to increase.
When you take candesartan, angiotensin II can’t activate the receptor as well as usual. As a result, the opposite happens:
- The muscles around your blood vessels relax, creating more space for the blood passing through.
- There is less blood in your body because your kidneys reabsorb less water and you excrete more in your urine.
Less blood pumping around blood vessels that are larger than usual means the pressure will be lower. If you think of it like a plumbing system, your cardiovascular system will be under less stress, which is a great help for your heart.
Candesartan is useful to lower blood pressure and reduce the pressure in your heart if you have hypertension or if you suffer from heart failure.
Side Effects
Sartans affect the body in various ways and there are several side effects that may occur when you take candesartan.
Low blood pressure (hypotension)
The most common side effects happen when candesartan is working too well and you end up with low blood pressure. You might notice:
- Headache
- Tiredness
- Dizziness
- Flushing
This is common when you first start taking candesartan or after a dose increase. It usually gets better after a few days, as your body gets used to the medication. If you still notice the effects after a week, the dose may be too high and your blood pressure too low as a result. You can check your blood pressure to find out at a pharmacy and ask your doctor about if you need to reduce the dose.
Excess Potassium (Hyperkalaemia)
Candesartan works by causing more water to be excreted in the urine than usual, which can upset the concentration of potassium in your body. Less potassium is excreted and it can build up and making you feel tired and have muscle weakness.
If you think you might have hyperkalemia, you can ask your doctor for a blood test to check if you have high potassium levels.
Cough
Rarely some people also get a dry cough when they take candesartan, which can be quite frustrating. If this affects you, you can talk to your doctor about alternative medication options for hypertension.
Cautions
There are a couple of things you should be aware of before you start taking candesartan, which are listed below
Angioedema
Candesartan may cause a swelling of your mouth and face, which can be dangerous if the airways become blocked. If this occurs, you should see a doctor as soon as possible.
Renal Impairment
Candesartan changes the function of the kidney and can increase the risk of renal impairment, particularly when used with other medications such as NSAIDS and diuretics. If you have poor kidney function, an alternative medication for hypertension is likely to be safer.
Stopping Suddenly
Candesartan is a long-term solution that is meant to be taken every day. If you stop taking it suddenly, your blood pressure may bounce back up, called rebound hypertension, because your body has adapted to taking the drug each day. Instead, it is best to gradually reduce the dose over a few weeks.
Drug Interactions
Lithium + Candesartan Interaction
Candesartan can decrease the amount of lithium that is excreted from the body and increase risk of side effects. The dose of lithium can be reduced to help manage this, or a different antihypertensive medication can be used.
Loop Diuretic + Candesartan Interaction
Taking a loop diuretic drug with candesartan can increase the risk of renal impairment and blood pressure that is too low, particularly for the first few doses. It is best to take a lower dose or to stop taking the loop diuretic for a few days when beginning to take a new dose.
NSAID + Candesartan Interaction
NSAIDs and candesartan can sometimes be used together in young and otherwise healthy patients, but it might not work as well to reduce your blood pressure and can lead to renal impairment.
Thiazide Diuretic + Candesartan Interaction
Taking a thiazide diuretic and candesartan together increases the risk of renal impairment and blood pressure that is too low, particularly for the first few doses. Using a lower dose is okay for some people but the combination is not recommended for others – you should talk to your doctor if you’re worried.
Pregnancy and Breastfeeding
Candesartan should not be used by women who are pregnant or planning to become pregnant because they can cause birth defects early in the pregnancy and may cause renal dysfunction of the fetus later in the pregnancy.
It is not recommended to take it while breastfeeding because there is limited research data available and we don’t know if it is safe.
