Atacand Side Effects: What to Expect and When to Call Your Doctor

Atacand (candesartan) is generally well-tolerated by most patients. In clinical trials involving more than 3,600 patients, most people experienced no or minimal side effects. However, like all medications, candesartan can cause side effects — and knowing which ones to watch for, and when to seek help, is an important part of your care.

This guide separates common, usually manageable side effects from serious ones that require prompt medical attention. It also covers candesartan's important boxed warning.

Boxed Warning: Do Not Use During Pregnancy

Candesartan carries an FDA boxed warning for fetal toxicity. This is the most serious type of warning the FDA issues. Drugs that act on the renin-angiotensin system — including candesartan — can cause injury or death to a developing fetus if taken during the second or third trimester of pregnancy. If you become pregnant while taking Atacand, stop the medication immediately and call your doctor.

If you are of childbearing age and taking candesartan, talk to your doctor about contraception and what to do if you plan to become pregnant. Candesartan should be switched to a pregnancy-safe blood pressure medication before you try to conceive.

Common Side Effects of Atacand

These side effects occurred in clinical trials and are generally mild and manageable:

Dizziness or lightheadedness: Most common when standing up quickly (orthostatic hypotension). More likely when first starting the medication or after a dose increase. Tip: rise slowly from a sitting or lying position and stay hydrated.

Headache: Reported in a small percentage of patients, usually early in treatment. Often improves as your body adjusts to the medication.

Back pain: Reported more commonly with candesartan than with some other ARBs, though still infrequent. Usually mild.

Upper respiratory symptoms: Nasal congestion, sore throat, or cold-like symptoms. Important note: unlike ACE inhibitors (lisinopril, enalapril), candesartan does NOT cause the persistent dry cough that makes many patients switch off ACE inhibitors.

Fatigue: Some patients report feeling more tired when starting candesartan. This often improves over time.

Serious Side Effects That Require Medical Attention

The following side effects are less common but serious. Contact your doctor promptly or seek emergency care if they occur:

Low blood pressure (hypotension): Signs include severe dizziness, fainting, or blurred vision. Most likely in patients who are dehydrated, on diuretics (water pills), or have a history of low sodium levels. Seek care if you faint.

High potassium (hyperkalemia): Symptoms include muscle weakness, irregular heartbeat, or numbness/tingling. More likely in patients with kidney disease or those taking potassium supplements. Your doctor will monitor your potassium with periodic blood tests.

Kidney function changes: Candesartan reduces pressure in the kidney filtration system. In patients with pre-existing kidney disease or with low blood volume, this can cause worsening kidney function. Your doctor will monitor creatinine and BUN with blood tests.

Angioedema: Rare but potentially life-threatening swelling of the face, lips, tongue, throat, or extremities. This can cause difficulty breathing. Seek emergency care immediately. Note: angioedema is much less common with ARBs than with ACE inhibitors, but can still occur.

Liver problems (rare): Abnormal liver function tests and rare cases of hepatitis have been reported post-marketing. Tell your doctor if you notice yellowing of the skin or eyes (jaundice), dark urine, or persistent nausea/abdominal pain.

The Key Advantage Over ACE Inhibitors: No Dry Cough

Many patients are switched to candesartan (Atacand) specifically because they developed a persistent, irritating dry cough from an ACE inhibitor like lisinopril or enalapril. This cough affects 10-15% of ACE inhibitor users and is caused by the buildup of bradykinin — a substance that ACE inhibitors allow to accumulate.

Candesartan works differently — it blocks the receptor rather than the converting enzyme, so it does not cause bradykinin accumulation and does NOT cause a dry cough. This is one of the primary clinical advantages of ARBs like candesartan over ACE inhibitors.

Monitoring Tests While on Atacand

Your doctor will typically order periodic blood tests to monitor:

Serum potassium — to watch for hyperkalemia

Serum creatinine and BUN — to monitor kidney function

Blood pressure — measured regularly in office or at home to ensure the medication is working

For a full review of medications that can increase your risk of side effects from candesartan, see our guide on Atacand drug interactions.