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Hydrochlorothiazide / losartan Side Effects

In Summary

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

For the Consumer

Applies to hydrochlorothiazide / losartan: oral tablet

In addition to its needed effects, some unwanted effects may be caused by hydrochlorothiazide / losartan. In the event that any of these side effects do occur, they may require medical attention.

Major Side Effects

You should check with your doctor immediately if any of these side effects occur when 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:
  • Coma
  • confusion
  • dark-colored urine
  • decreased urine output
  • dry mouth
  • fast or irregular heartbeat
  • fever
  • increased thirst
  • irritability
  • 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
  • muscle cramps or pain
  • muscle spasms
  • muscle stiffness
  • muscle twitching
  • nausea or vomiting
  • painful knees and ankles
  • raised red swellings on the skin, the buttocks, legs, or ankles
  • restlessness
  • seizures
  • shortness of breath
  • swelling of the face, ankles, or hands
  • upper right abdominal or stomach pain
  • unusual tiredness or weakness
  • weak or irregular heartbeat
  • yellow eyes and skin

Minor Side Effects

Some of the side effects that can occur with hydrochlorothiazide / losartan may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

Less common:
  • Cold or flu-like symptoms
  • dizziness
  • headache
  • increased sensitivity of the skin to sunlight
  • sore throat
  • stomach pain
  • Dry cough
  • sinus problems

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 (losartan-hydrochlorothiazide)." Merck & Co, Inc, West Point, PA.

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

Not all side effects for hydrochlorothiazide / losartan may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

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