Skip to main content

Hyzaar Side Effects

Generic name: hydrochlorothiazide / losartan

Medically reviewed by Last updated on Aug 12, 2022.

Note: This document contains side effect information about hydrochlorothiazide / losartan. Some of the dosage forms listed on this page may not apply to the brand name Hyzaar.


More frequent side effects include: dizziness. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to hydrochlorothiazide / losartan: oral tablet


Oral route (Tablet)

Drugs that act directly on the renin-angiotensin system can cause injury or death to the developing fetus. Stop therapy as soon as possible when pregnancy is detected.

Side effects requiring immediate medical attention

Along with its needed effects, hydrochlorothiazide/losartan may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking hydrochlorothiazide / losartan:


  • Black, tarry stools
  • blood in the urine or stools
  • cough or hoarseness accompanied by chills or fever, lower back or side pain, or painful or difficult urination
  • fainting
  • pinpoint red spots on the skin
  • pounding heartbeat
  • severe stomach pain, nausea, and vomiting
  • skin rash
  • swelling of the feet or lower legs
  • unusual bleeding or bruising

Incidence not known

  • Bleeding gums
  • blistering, peeling, loosening of the skin
  • blurred vision
  • chest pain or tightness
  • chills
  • coma
  • confusion
  • cough
  • dark-colored urine
  • decreased frequency of urine
  • decreased urine output
  • diarrhea
  • difficulty swallowing
  • dizziness
  • dry mouth
  • fast, irregular, pounding, or racing heartbeat or pulse
  • fever
  • hives, itching skin, rash
  • increased sensitivity of the skin to sunlight
  • increased thirst
  • irritability
  • joint or muscle pain
  • large, flat, blue, or purplish patches in the skin
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • light-colored stools
  • loss of appetite
  • lower back or side pain
  • muscle cramps, pain, spasms, stiffness, or twitching
  • nausea or vomiting
  • numbness or tingling in the hands, feet, or lips
  • painful knees and ankles
  • persistent non-healing sore
  • pink growth
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • raised red swellings on the skin, the buttocks, legs, or ankles
  • red, irritated eyes
  • red skin lesions, often with a purple center
  • reddish patch or irritated area
  • redness or other discoloration of the skin
  • restlessness
  • seizures
  • severe sunburn
  • shiny bump
  • sore throat
  • sores, ulcers, or white spots in the mouth or on the lips
  • swelling of the face, ankles, or hands
  • trouble breathing
  • upper right abdominal or stomach pain
  • unusual tiredness or weakness
  • weak or irregular heartbeat
  • weight gain
  • white, yellow or waxy scar-like area
  • yellow eyes and skin

Side effects not requiring immediate medical attention

Some side effects of hydrochlorothiazide / losartan may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common


  • Dry cough

Incidence not known

  • Acid or sour stomach
  • belching
  • change or loss of taste
  • difficulty having a bowel movement (stool)
  • general feeling of discomfort or illness
  • heartburn
  • inability to have or keep an erection
  • indigestion
  • loss in sexual ability, desire, drive, or performance
  • trouble sleeping
  • weight loss

For Healthcare Professionals

Applies to hydrochlorothiazide / losartan: oral tablet


The most common adverse reaction was dizziness.[Ref]

Nervous system

Common (1% to 10%): Dizziness, headache


Frequency not reported: Syncope, cerebrovascular accident, ataxia, hypesthesia, memory impairment, migraine, paresthesia, peripheral neuropathy, somnolence, vertigo, tremor, taste perversion, tinnitus[Ref]


Common (1% to 10%): Cough, sinusitis, upper respiratory infection, bronchitis, pharyngitis


Frequency not reported: Respiratory distress, pneumonitis, pulmonary edema


Frequency not reported: Dyspnea, epistaxis, nasal congestion, pharyngeal discomfort, respiratory congestion, rhinitis, sinus disorder

Postmarketing reports: Dry cough[Ref]


Common (1% to 10%): Abdominal pain, diarrhea, nausea


Frequency not reported: Pancreatitis, sialadenitis, cramping, gastric irritation


Frequency not reported: Constipation, dental pain, dry mouth, dyspepsia, flatulence, gastritis, vomiting[Ref]


Common (1% to 10%): Palpitation, essential hypertension

Uncommon (0.1% to 1%): Hypotension


Frequency not reported: Vasculitis


Frequency not reported: Angina pectoris, arrhythmias, atrial fibrillation, sinus bradycardia, tachycardia, ventricular tachycardia, ventricular fibrillation, hypotension, myocardial infarction, second degree atrioventricular block, flushing

Postmarketing reports: Vasculitis[Ref]


Common (1% to 10%): Edema/swelling, asthenia/fatigue


Frequency not reported: Weakness, fever


Frequency not reported: Chest pain, facial edema, fever, orthostatic effects, malaise[Ref]


Common (1% to 10%): Rash


Frequency not reported: Purpura, photosensitivity, urticaria, cutaneous vasculitis, erythema multiforme, Stevens-Johnson syndrome, exfoliative dermatitis, toxic epidermal necrolysis


Common (1% to 10%): Rash

Frequency not reported: Angioedema, superficial peeling of palms, alopecia, dermatitis, dry skin, ecchymosis, erythema, photosensitivity, pruritus, sweating, urticaria

Postmarketing reports: Erythroderma[Ref]


Common (1% to 10%): Back pain


Frequency not reported: Muscle spasm


Frequency not reported: Arm pain, arthralgia, arthritis, fibromyalgia, hip pain, joint swelling, knee pain, leg pain, muscle cramps, muscle weakness, musculoskeletal pain, myalgia, shoulder pain, stiffness

Postmarketing reports: Rhabdomyolysis[Ref]


Uncommon (0.1% to 1%): Serum creatinine increased greater than 5 mg/dL, BUN increased


Frequency not reported: Renal failure, renal dysfunction, interstitial nephritis


Common (1% to 10%): Serum creatinine increased greater than 5 mg/dL[Ref]


Frequency not reported: Liver enzymes elevated, serum bilirubin elevated

Postmarketing reports: Hepatitis


Frequency not reported: Intrahepatic cholestatic jaundice


Postmarketing reports: Hepatitis[Ref]


Frequency not reported: Hemoglobin decreased, hematocrit decreased


Frequency not reported: Aplastic anemia, agranulocytosis, leukopenia, hemolytic anemia, thrombocytopenia


Frequency not reported: Hemolysis, anemia[Ref]


Postmarketing reports: Hyperkalemia


Frequency not reported: Hyperglycemia, hyperuricemia


Frequency not reported: Anorexia, gout

Postmarketing reports: Hyperkalemia, hyponatremia[Ref]



Frequency not reported: Transient blurred vision, xanthopsia


Frequency not reported: Blurred vision, burning/stinging in the eye, conjunctivitis, visual acuity decreased[Ref]



Frequency not reported: Restlessness


Frequency not reported: Anxiety, anxiety disorder, confusion, dream abnormality, depression, insomnia, libido decreased, nervousness, panic disorder, sleep disorder[Ref]



Frequency not reported: Glycosuria


Frequency not reported: Impotence, nocturia, urinary frequency, urinary tract infection[Ref]



Postmarketing reports: Anaphylactic reactions[Ref]


1. "Product Information. Hyzaar (hydrochlorothiazide-losartan)." Merck & Company Inc (2022):

2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.