Hydrochlorothiazide/Lisinopril Side Effects: What to Expect and When to Call Your Doctor

Hydrochlorothiazide/Lisinopril is generally well-tolerated, and millions of patients take it daily with few or no problems. But like all medications, it can cause side effects. Some are common and manageable; others are serious and require immediate medical attention. Knowing the difference can help you stay safe and make informed decisions about your treatment.

Important Warning: Do Not Take During Pregnancy

Hydrochlorothiazide/Lisinopril carries a Black Box Warning — the FDA's most serious safety alert. It must NOT be used during pregnancy. Drugs that act on the renin-angiotensin system, including lisinopril, can cause injury and death to a developing fetus, particularly in the second and third trimesters. If you become pregnant while taking this medication, stop immediately and contact your doctor.

Common Side Effects (Usually Manageable)

These side effects occur in approximately 1-10% of patients and are often mild:

• Dry cough: Caused by the lisinopril (ACE inhibitor) component. Affects roughly 10-20% of patients. It's persistent and often described as a tickling sensation in the throat. If bothersome, your doctor may switch you to an ARB like losartan, which does not cause this cough.
• Dizziness and lightheadedness: Especially when standing up quickly (orthostatic hypotension). Most common when starting the medication. Rise slowly from sitting or lying positions.
• Headache: Common when first starting; usually resolves within the first few weeks.
• Fatigue: Some patients feel tired, particularly early in treatment. Usually improves over time.
• Increased urination: From the hydrochlorothiazide (diuretic) component. Most noticeable in the first few weeks; your body typically adjusts.
• Mild nausea: Can occur when starting; taking the medication with food may help.

Serious Side Effects (Call Your Doctor)

These side effects are less common but require medical attention. Contact your doctor if you experience:

• Low potassium (hypokalemia): Symptoms include leg cramps, muscle weakness, constipation, irregular heartbeat, or numbness and tingling. The HCTZ component causes potassium loss, though lisinopril partially counterbalances this. Regular blood tests can catch this early.
• Low sodium (hyponatremia): Symptoms include headache, confusion, slurred speech, severe weakness, vomiting, or feeling unsteady. Older patients and those on low-sodium diets are at higher risk.
• High potassium (hyperkalemia): Lisinopril can raise potassium levels. Symptoms include muscle weakness and irregular heartbeat. Risk is higher in patients with kidney disease or those taking potassium supplements.
• Kidney problems: Signs include decreased urination, swelling of the ankles or feet. Your doctor should monitor kidney function (creatinine, BUN) periodically.

Emergency Side Effects (Seek Immediate Care)

These side effects require immediate emergency attention — call 911 or go to the ER:

• Angioedema: Sudden swelling of the face, lips, tongue, throat, hands, or feet. Throat swelling can block the airway and be life-threatening. Stop the medication immediately and call 911. Do NOT restart any ACE inhibitor if this occurs.
• Severe hypotension: Sudden, extreme drop in blood pressure causing fainting or near-fainting. Most likely if you are dehydrated or have been vomiting/having diarrhea.
• Acute angle-closure glaucoma: Sudden eye pain, blurred vision, or rapid loss of vision — a rare but serious reaction to the HCTZ component. Seek immediate eye care.
• Signs of liver damage: Right upper abdominal pain, yellowing of skin or eyes (jaundice), dark urine, loss of appetite. Rare but requires immediate evaluation.

Sun Sensitivity

Hydrochlorothiazide increases your skin's sensitivity to sunlight and UV rays. This not only raises your risk of sunburn but has also been associated with an increased long-term risk of non-melanoma skin cancers with prolonged use. Wear sunscreen (SPF 30 or higher) and protective clothing when outdoors, and discuss regular skin checks with your doctor.

For information about drug interactions with Hydrochlorothiazide/Lisinopril, see: Hydrochlorothiazide/Lisinopril Drug Interactions: What to Avoid. If you're having trouble finding your medication, medfinder can help locate pharmacies near you with it in stock.