Candesartan
Angiotensin II Receptor Blocker (ARB) for High Blood Pressure & Heart Failure
Candesartan is a prescription medicine belonging to the angiotensin II receptor blocker (ARB) class. It is used to treat high blood pressure (hypertension) in adults and children aged 6–18, and to manage heart failure with reduced cardiac function in adults. By blocking the action of angiotensin II, candesartan relaxes and widens blood vessels, lowering blood pressure and reducing the workload on the heart.
Quick Facts
Key Takeaways
- Candesartan is an angiotensin II receptor blocker (ARB) that lowers blood pressure by relaxing blood vessels and reducing cardiac workload.
- It is approved for hypertension in adults and children aged 6–18, and for heart failure with reduced ejection fraction in adults.
- Candesartan must not be taken during pregnancy (especially the 2nd and 3rd trimesters), as it can cause serious harm to the unborn baby.
- Common side effects include dizziness, headache, and respiratory infections; elevated potassium levels and kidney function changes should be monitored.
- Dual blockade of the renin-angiotensin system (combining candesartan with ACE inhibitors or aliskiren) is generally not recommended due to increased risk of adverse effects.
What Is Candesartan and What Is It Used For?
Candesartan cilexetil is the active substance in medicines marketed under brand names such as Atacand, Candesartan Krka, Candesartan STADA, Kandrozid, Candesarstad, Kairasec, Candesartan Sandoz, and Candesartan Orion. It belongs to a group of medicines known as angiotensin II receptor antagonists (also called ARBs or sartans). These medicines act by selectively blocking the angiotensin II type 1 (AT1) receptor, which plays a central role in regulating blood pressure and fluid balance.
When angiotensin II binds to the AT1 receptor, it causes blood vessels to constrict and stimulates the release of aldosterone, a hormone that promotes sodium and water retention. By blocking this receptor, candesartan allows blood vessels to relax and dilate, leading to a reduction in blood pressure. It also decreases the secretion of aldosterone, which helps the body excrete excess sodium and water. This dual action makes candesartan an effective treatment for conditions characterized by elevated blood pressure or cardiac dysfunction.
Approved Indications
Candesartan is approved by regulatory agencies including the European Medicines Agency (EMA) and the U.S. Food and Drug Administration (FDA) for the following uses:
- Hypertension (high blood pressure): Treatment of essential hypertension in adults and in children and adolescents aged 6 to 18 years. According to the 2023 ESC/ESH Guidelines for the Management of Arterial Hypertension, ARBs such as candesartan are considered first-line agents for blood pressure control.
- Heart failure: Treatment of adult patients with heart failure and reduced left ventricular systolic function (ejection fraction ≤40%) when angiotensin-converting enzyme (ACE) inhibitors cannot be used, or as add-on therapy to ACE inhibitors when symptoms persist despite treatment and mineralocorticoid receptor antagonists (MRAs) cannot be used.
The landmark CHARM (Candesartan in Heart failure: Assessment of Reduction in Mortality and morbidity) programme, comprising three parallel randomised controlled trials involving over 7,600 patients, demonstrated that candesartan significantly reduced cardiovascular death and hospitalisation for heart failure. This evidence forms the basis for candesartan's widespread use in clinical practice for heart failure management.
Candesartan may also be prescribed off-label for migraine prophylaxis. A randomised, double-blind, placebo-controlled crossover study published in JAMA found that candesartan 16 mg daily was as effective as propranolol for migraine prevention, providing a well-tolerated alternative for patients who cannot use beta-blockers.
What Should You Know Before Taking Candesartan?
Contraindications
Candesartan must not be taken in the following situations:
- Allergy: If you are allergic to candesartan cilexetil or any of the other ingredients in the medicine (including lactose monohydrate, hydroxypropyl cellulose, carmellose calcium, magnesium stearate, maize starch, and macrogol).
- Pregnancy: Candesartan must not be used after the first trimester of pregnancy, and is not recommended during early pregnancy. It can cause serious and potentially fatal harm to the developing baby, including renal failure, oligohydramnios (low amniotic fluid), skull hypoplasia, and neonatal death.
- Severe liver disease or biliary obstruction: Patients with severe hepatic impairment or cholestasis (problems with bile drainage from the gallbladder) must not use candesartan.
- Children under 1 year: Candesartan must not be given to infants under 1 year of age due to the potential risk to developing kidneys.
- Dual RAAS blockade: Concomitant use with aliskiren-containing products is contraindicated in patients with diabetes mellitus or renal impairment (GFR <60 mL/min/1.73 m²).
Warnings and Precautions
Before starting candesartan, you should inform your doctor if any of the following conditions apply to you:
- Kidney problems: Including prior kidney transplant, renal artery stenosis, or being on dialysis. Candesartan can affect kidney function and your doctor will need to monitor your renal parameters and potassium levels regularly.
- Heart conditions: Including coronary artery disease, congestive heart failure, or aortic/mitral valve stenosis. Dose adjustments and close monitoring may be required.
- Liver disease: Mild to moderate hepatic impairment may require a lower starting dose.
- Volume or sodium depletion: If you have had recent vomiting, severe diarrhoea, or are taking high-dose diuretics, you may be at increased risk of symptomatic hypotension (low blood pressure) when starting candesartan. Your doctor may correct volume depletion before initiating treatment or start with a lower dose.
- Primary hyperaldosteronism (Conn's syndrome): Patients with this adrenal gland disorder generally do not respond well to medicines that act on the renin-angiotensin system.
- Low blood pressure: If you already have low blood pressure, candesartan may exacerbate it.
- Previous stroke: Inform your doctor if you have had a stroke, as blood pressure management in these patients requires careful consideration.
- Surgery or anaesthesia: Tell your doctor or dentist that you are taking candesartan if you are scheduled for any procedure. Candesartan taken alongside certain anaesthetic agents may cause an additional blood pressure drop.
Do not combine candesartan with an ACE inhibitor (e.g. enalapril, lisinopril, ramipril) or aliskiren, especially if you have diabetes-related kidney problems. This combination (known as dual renin-angiotensin-aldosterone system blockade) increases the risk of dangerously low blood pressure, elevated potassium levels, and acute kidney injury. The 2023 ESC/ESH Hypertension Guidelines explicitly advise against routine dual RAAS blockade.
Pregnancy and Breastfeeding
Pregnancy: You must inform your doctor if you think you might be (or could become) pregnant. Your doctor will usually advise you to stop candesartan before you become pregnant, or as soon as you learn you are pregnant, and will prescribe an alternative medication. Candesartan is not recommended during the first trimester and is strictly contraindicated during the second and third trimesters. Use during these stages can cause serious damage to the developing baby, including:
- Fetal renal dysfunction and anuria
- Oligohydramnios (reduced amniotic fluid volume)
- Skull ossification defects
- Limb contractures and lung hypoplasia
- Neonatal hypotension and death
Breastfeeding: Candesartan is not recommended for breastfeeding mothers. It is not known whether candesartan is excreted in human breast milk, but it is present in rat milk. Your doctor may choose an alternative treatment if you wish to breastfeed, particularly if your baby is a newborn or was born prematurely.
Driving and Operating Machinery
Some patients may experience dizziness or fatigue while taking candesartan. If you are affected, you should not drive, cycle, or operate machinery until you know how the medicine affects you. This is particularly important at the start of treatment or after dose increases.
Lactose Content
Candesartan tablets contain lactose monohydrate as an inactive ingredient. If you have been told by your doctor that you have an intolerance to some sugars, contact your doctor before taking this medicine.
How Does Candesartan Interact with Other Drugs?
Drug interactions can alter how candesartan works or increase the risk of serious side effects. It is essential to inform your doctor or pharmacist about all medicines you take, have recently taken, or plan to take, including over-the-counter products, supplements, and herbal remedies. Your doctor may need to adjust doses, monitor blood tests more frequently, or consider alternative treatments.
Major Interactions
The following interactions are considered clinically significant and require careful management or avoidance:
| Drug / Drug Class | Interaction Effect | Clinical Significance |
|---|---|---|
| ACE inhibitors (enalapril, lisinopril, ramipril) | Dual RAAS blockade increases risk of hypotension, hyperkalemia, and renal impairment | Generally avoid combination; contraindicated in diabetic nephropathy |
| Aliskiren | Dual RAAS blockade with increased risk of adverse renal and cardiovascular events | Contraindicated in diabetes or GFR <60; avoid in all other patients |
| Potassium supplements / potassium-sparing diuretics (spironolactone, eplerenon, amiloride) | Additive hyperkalemia risk; potentially life-threatening cardiac arrhythmias | Monitor potassium levels closely; use combination with caution |
| Lithium | Increased serum lithium concentrations leading to lithium toxicity (tremor, confusion, seizures) | Monitor lithium levels frequently if combination is necessary; consider dose reduction |
| Heparin | Additive hyperkalemia risk | Monitor potassium levels when used together |
| Trimethoprim / sulfamethoxazole | Increased risk of hyperkalemia, particularly in patients with renal impairment | Monitor potassium levels; consider alternative antibiotics if possible |
Minor Interactions
The following interactions may be clinically relevant but can usually be managed with monitoring or dose adjustments:
| Drug / Drug Class | Interaction Effect | Clinical Significance |
|---|---|---|
| NSAIDs (ibuprofen, naproxen, diclofenac, celecoxib) | May reduce the blood pressure-lowering effect of candesartan; increased risk of renal impairment and hyperkalemia | Use with caution; ensure adequate hydration; monitor renal function |
| Aspirin (>3 g/day) | May reduce antihypertensive effect at high doses | Low-dose aspirin for cardiovascular prevention is generally safe |
| Diuretics (furosemide, hydrochlorothiazide) | Additive blood pressure-lowering effect; risk of symptomatic hypotension, especially at initiation | Start candesartan at a lower dose; monitor blood pressure carefully |
| Other antihypertensives (beta-blockers, calcium channel blockers, diazoxide) | Additive blood pressure-lowering effect | Combination therapy is common and effective but requires blood pressure monitoring |
Food and Alcohol Interactions
Food: Candesartan can be taken with or without food. Food does not significantly affect the absorption or efficacy of the medicine. However, patients should be advised to avoid excessive consumption of potassium-rich foods (bananas, oranges, potatoes, spinach) or salt substitutes containing potassium, as these may increase the risk of hyperkalemia when combined with candesartan.
Alcohol: Alcohol may enhance the blood pressure-lowering and dizziness-inducing effects of candesartan. If you are prescribed candesartan, discuss your alcohol consumption with your doctor. Some patients may experience lightheadedness, faintness, or dizziness if they drink alcohol while taking this medicine.
What Is the Correct Dosage of Candesartan?
Candesartan should always be taken exactly as your doctor has prescribed. Take the tablet with a glass of water, with or without food. Try to take it at the same time each day to help you remember. The full blood pressure-lowering effect is typically achieved within 4 weeks of starting treatment.
Adults — Hypertension
| Parameter | Dose | Notes |
|---|---|---|
| Starting dose | 8 mg once daily | May be lower (4 mg) in patients with volume depletion, liver/kidney problems, or those on diuretics |
| Dose titration | 8 mg → 16 mg → 32 mg | Increase at 2–4 week intervals based on blood pressure response |
| Maximum dose | 32 mg once daily | Most patients achieve adequate blood pressure control at 8–16 mg daily |
| Administration | Once daily, with or without food | Take at the same time each day; swallow tablet whole with water |
For patients with hepatic impairment, a lower starting dose of 4 mg may be appropriate. In patients with intravascular volume depletion (e.g. from diuretic therapy, dietary salt restriction, dialysis, diarrhoea, or vomiting), candesartan should be initiated at 4 mg under close medical supervision due to the risk of symptomatic hypotension.
Some patients of Black African descent may have a diminished blood pressure response to ARB monotherapy. These patients may benefit from a higher dose or combination therapy with a thiazide diuretic or calcium channel blocker, consistent with current ESC/ESH and AHA/ACC guideline recommendations for managing hypertension in diverse populations.
Children and Adolescents — Hypertension
Candesartan has been studied in children and adolescents aged 6 to 18 years for the treatment of hypertension. It must not be used in children under 1 year of age.
| Body Weight | Starting Dose | Maximum Dose |
|---|---|---|
| <50 kg | 4 mg once daily | 8 mg once daily |
| ≥50 kg | 4 mg once daily | 16 mg once daily |
In children, the dose may be increased by the doctor if blood pressure control remains inadequate after at least 2 weeks. The dosage should be adjusted based on the child's blood pressure response and tolerability.
Elderly Patients
No initial dose adjustment is generally required in elderly patients with normal renal and hepatic function. However, careful dose titration is recommended starting at the lower end of the dosing range, as elderly patients are more susceptible to hypotension and may have reduced renal function. Regular monitoring of blood pressure, kidney function, and electrolytes is advisable.
Heart Failure in Adults
Heart Failure Dosing Protocol
- Starting dose: 4 mg once daily
- Titration: Double the dose at intervals of at least 2 weeks (4 mg → 8 mg → 16 mg → 32 mg)
- Target dose: 32 mg once daily, or the highest tolerated dose
- Monitoring: Renal function and potassium levels should be checked at each dose increase
Candesartan can be taken together with other heart failure medicines including ACE inhibitors (in some cases under specialist supervision), beta-blockers, diuretics, and digoxin. Your doctor will determine which combination is most appropriate for you.
Missed Dose
If you forget to take a dose, take it as soon as you remember. However, if it is almost time for your next dose, skip the missed dose and continue with your normal schedule. Do not take a double dose to make up for a forgotten tablet. Setting a daily alarm or keeping your medicine in a visible location can help establish a routine.
Overdose
If you take more candesartan than prescribed, or if a child accidentally swallows the medicine, seek medical advice immediately by contacting your doctor, going to the nearest emergency department, or calling your local poison control centre. Symptoms of overdose may include dizziness, lightheadedness, and dangerously low blood pressure (hypotension). Treatment is supportive and may include intravenous fluid replacement to restore blood pressure. Candesartan is not effectively removed by haemodialysis.
Do not stop taking candesartan without first consulting your doctor, even if you feel well. High blood pressure often has no symptoms, and stopping treatment suddenly may cause your blood pressure to rise again, increasing the risk of cardiovascular events such as heart attack and stroke.
What Are the Side Effects of Candesartan?
Like all medicines, candesartan can cause side effects, although not everyone will experience them. Most side effects are mild and tend to resolve as your body adjusts to the medicine. However, it is important to be aware of potentially serious reactions that require immediate medical attention.
Stop taking candesartan and seek emergency medical care immediately if you experience any of the following allergic reactions:
- Difficulty breathing, with or without swelling of the face, lips, tongue, and/or throat
- Swelling of the face, lips, tongue, and/or throat that makes it difficult to swallow (angioedema)
- Severe itching of the skin with raised rashes (urticaria)
Candesartan may also cause a decrease in white blood cell count (agranulocytosis). Your resistance to infections may be reduced, and you may experience fatigue, infection, or fever. If this happens, contact your doctor promptly so a blood test can be performed.
Side Effect Frequency
Common
Affects 1 to 10 in every 100 patients
- Dizziness and lightheadedness
- Headache
- Respiratory tract infection
- Low blood pressure (hypotension) — may cause faintness or dizziness
- Increased potassium levels in the blood (hyperkalemia), especially in patients with existing kidney problems or heart failure
- Changes in kidney function tests, especially in patients with existing kidney problems or heart failure
Very Rare
Affects fewer than 1 in 10,000 patients
- Intestinal angioedema — swelling of the intestine causing abdominal pain, nausea, vomiting, and diarrhoea
- Angioedema — swelling of the face, lips, tongue, and/or throat
- Reduction in red or white blood cell count — may cause fatigue, infections, or fever
- Skin rash, itchy bumpy rash (urticaria), and pruritus
- Back pain, joint pain, and muscle pain
- Changes in liver function, including hepatitis (liver inflammation) — may cause fatigue, yellowing of the skin and eyes, flu-like symptoms
- Nausea
- Decreased sodium levels in the blood (hyponatremia) — may cause weakness, lack of energy, or muscle cramps
- Cough
Frequency Not Known
Cannot be estimated from available data
- Diarrhoea
Side Effects in Children
The side effects observed in children treated for high blood pressure appear to be comparable to those seen in adults, but they occur more frequently. In particular:
- Very common in children (not reported in adults): Sore throat (pharyngitis)
- Common in children (not reported in adults): Runny nose (rhinitis), fever, and increased heart rate (tachycardia)
Parents and caregivers should monitor children taking candesartan for these symptoms and report any concerns to their doctor. Regular follow-up appointments are important for children receiving long-term antihypertensive therapy to monitor growth, development, kidney function, and electrolyte balance.
Reporting Side Effects
If you experience any side effects, including those not listed above, talk to your doctor or pharmacist. You can also report side effects directly to your national pharmacovigilance authority (e.g. the FDA MedWatch programme in the United States, the Yellow Card Scheme in the United Kingdom, or the EMA EudraVigilance system in the European Union). By reporting side effects, you help provide important information about the ongoing safety of this medicine.
How Should You Store Candesartan?
Proper storage of medicines is essential to maintain their effectiveness and safety. Follow these guidelines for storing candesartan:
- Temperature: No special temperature storage conditions are required. Store at room temperature (typically 15–30°C / 59–86°F). Avoid storing near heat sources or in direct sunlight.
- Moisture: Keep the tablets in their original packaging (blister pack or container) to protect them from moisture. Do not store in the bathroom or other humid environments.
- Children: Keep this medicine out of the sight and reach of children. Consider using child-resistant containers.
- Expiry date: Do not use candesartan after the expiry date shown on the carton, blister pack, or container after "EXP". The expiry date refers to the last day of that month.
- Disposal: Do not dispose of medicines via wastewater or household waste. Ask your pharmacist how to dispose of medicines you no longer use. These measures help protect the environment.
What Does Candesartan Contain?
Active Ingredient
The active substance is candesartan cilexetil. This is a prodrug that is rapidly and completely converted to the active metabolite candesartan during absorption from the gastrointestinal tract. Candesartan cilexetil itself has no pharmacological activity; all therapeutic effects are mediated by the active form, candesartan.
Inactive Ingredients (Excipients)
The tablets contain the following inactive ingredients: carmellose calcium, hydroxypropyl cellulose, lactose monohydrate, magnesium stearate, maize starch (corn starch), and macrogol (polyethylene glycol). The 8 mg, 16 mg, and 32 mg strength tablets also contain iron oxide (E172) as a colouring agent, which gives these tablets their pink colour.
Tablet Appearance
| Strength | Colour | Shape | Markings |
|---|---|---|---|
| 4 mg | White | Round, scored | A/CF on one side, 004 on the other |
| 8 mg | Light pink | Round, scored | A/CG on one side, 008 on the other |
| 16 mg | Pink | Round, scored | A/CH on one side, 016 on the other |
| 32 mg | Pink | Round, scored | A/CL on one side, 032 on the other |
All tablets are scored and can be divided into two equal halves. Tablets are available in blister packs (7, 14, 28, 30, 56, 90, or 98 tablets) or plastic containers (100 tablets). Not all pack sizes may be marketed in all countries. Generic formulations may have different appearances and markings depending on the manufacturer.
Frequently Asked Questions About Candesartan
Candesartan is primarily used to treat high blood pressure (hypertension) in adults and children aged 6 to 18 years. It is also used to treat heart failure with reduced left ventricular systolic function in adults when ACE inhibitors cannot be used, or as add-on therapy when symptoms persist despite ACE inhibitor treatment. Candesartan belongs to a class of medicines called angiotensin II receptor blockers (ARBs).
No. Candesartan must not be taken during the second and third trimesters of pregnancy, as it can cause serious harm to the developing baby, including kidney damage, low amniotic fluid, skull malformations, and even death. It is also not recommended during early pregnancy. Women who are pregnant or planning to become pregnant should inform their doctor immediately so an alternative medication can be prescribed.
Common side effects (affecting 1 to 10 in every 100 patients) include dizziness, headache, respiratory tract infections, and low blood pressure (which may cause faintness). Blood test changes such as elevated potassium levels and effects on kidney function may also occur, particularly in patients with pre-existing kidney problems or heart failure. Most side effects are mild and temporary. Contact your doctor if any side effects become persistent or troublesome.
Candesartan begins to lower blood pressure within 2 hours of taking the first dose. However, the full blood pressure-lowering effect is typically achieved within 4 weeks of continuous treatment. Your doctor may adjust the dose during this period to find the most effective dose for you. It is important to keep taking candesartan every day, even if you feel well, as high blood pressure often has no symptoms.
Candesartan can be combined with certain other blood pressure medications such as diuretics (water pills) or calcium channel blockers under medical supervision. However, the combination of candesartan with ACE inhibitors (e.g. enalapril, ramipril) or aliskiren is generally not recommended due to increased risk of hyperkalemia, low blood pressure, and kidney problems. Always inform your doctor about all medications you are taking.
If you miss a dose, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for the missed one. Setting a daily reminder or taking candesartan at the same time each day can help prevent missed doses.
Candesartan and losartan both belong to the same class of drugs called angiotensin II receptor blockers (ARBs) and work by a similar mechanism. However, they are different molecules with different pharmacokinetic properties. Candesartan has a longer duration of action and is generally considered to provide more consistent 24-hour blood pressure control compared to losartan. Your doctor will choose the most appropriate ARB based on your individual clinical circumstances.
References
This article is based on peer-reviewed medical literature, international clinical guidelines, and approved prescribing information from regulatory authorities. All medical claims follow the GRADE evidence framework.
- European Medicines Agency (EMA). Atacand (candesartan cilexetil) – Summary of Product Characteristics. Last updated 2025.
- U.S. Food and Drug Administration (FDA). Atacand (candesartan cilexetil) – Prescribing Information. Reference ID: 4834715.
- Pfeffer MA, Swedberg K, Granger CB, et al. Effects of candesartan on mortality and morbidity in patients with chronic heart failure: the CHARM-Overall programme. Lancet. 2003;362(9386):759-766. doi:10.1016/S0140-6736(03)14282-1
- McMurray JJV, Östergren J, Swedberg K, et al. Effects of candesartan in patients with chronic heart failure and reduced left-ventricular systolic function taking angiotensin-converting-enzyme inhibitors: the CHARM-Added trial. Lancet. 2003;362(9386):767-771.
- Yusuf S, Pfeffer MA, Swedberg K, et al. Effects of candesartan in patients with chronic heart failure and preserved left-ventricular ejection fraction: the CHARM-Preserved Trial. Lancet. 2003;362(9386):777-781.
- Mancia G, Kreutz R, Brunström M, et al. 2023 ESH Guidelines for the management of arterial hypertension. J Hypertens. 2023;41(12):1874-2071. doi:10.1097/HJH.0000000000003480
- McDonagh TA, Metra M, Adamo M, et al. 2021 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure. Eur Heart J. 2021;42(36):3599-3726.
- Stovner LJ, Linde M, Gravdahl GB, et al. A comparative study of candesartan versus propranolol for migraine prophylaxis: a randomised, triple-blind, placebo-controlled, double cross-over study. Cephalalgia. 2014;34(7):523-532.
- World Health Organization (WHO). WHO Model List of Essential Medicines – 23rd list (2023). Geneva: World Health Organization; 2023.
- National Institute for Health and Care Excellence (NICE). Hypertension in adults: diagnosis and management [NG136]. Last updated 2022.
- British National Formulary (BNF). Candesartan cilexetil monograph. Accessed January 2026.
Medical Editorial Team
This article has been developed and reviewed by the iMedic Medical Editorial Team, comprising licensed physicians with specialist training in clinical pharmacology, cardiology, and internal medicine. All content follows international guidelines from the WHO, EMA, FDA, and NICE.
Drug information, dosage recommendations, interactions, and pharmacokinetic data verified against EMA SmPC and FDA prescribing information.
Heart failure and hypertension content reviewed against ESC/ESH 2023 Guidelines and ACC/AHA recommendations.
All clinical claims evaluated using the GRADE framework. Evidence level: 1A (systematic reviews and RCTs including the CHARM programme).
Content written at a reading level accessible to the general public while maintaining clinical accuracy. WCAG 2.2 AAA compliant.
Conflict of Interest Statement: The iMedic Medical Editorial Team has no financial relationships with pharmaceutical companies. This content is independently produced with no commercial funding or advertising sponsorship.