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Cozaar Side Effects

Generic Name: losartan

Note: This page contains information about the side effects of losartan. Some of the dosage forms included on this document may not apply to the brand name Cozaar.

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

For the Consumer

Applies to losartan: oral tablet

In addition to its needed effects, some unwanted effects may be caused by losartan (the active ingredient contained in Cozaar). In the event that any of these side effects do occur, they may require medical attention.

You should check with your doctor immediately if any of these side effects occur when taking losartan:

More common
  • Abdominal or stomach pain
  • anxiety
  • bladder pain
  • bloody or cloudy urine
  • blurred vision
  • chills
  • cold sweats
  • coma
  • confusion
  • cool, pale skin
  • depression
  • difficult breathing
  • difficult, burning, or painful urination
  • dizziness
  • fast heartbeat
  • frequent urge to urinate
  • headache
  • increased hunger
  • irregular heartbeat
  • lower back or side pain
  • nausea or vomiting
  • nightmares
  • numbness or tingling in the hands, feet, or lips
  • pale skin
  • seizures
  • shakiness
  • shortness of breath
  • slurred speech
  • troubled breathing with exertion
  • unusual bleeding or bruising
  • unusual tiredness or weakness
  • weakness or heaviness of the legs
  • Arm, back, or jaw pain
  • chest pain or discomfort
  • chest tightness or heaviness
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • fainting
  • fast, irregular, pounding, or racing heartbeat or pulse
  • inability to speak
  • pain or discomfort in the arms, jaw, back, or neck
  • severe or sudden headache
  • sweating
  • swelling or puffiness of the face
  • temporary blindness
  • unsteadiness or awkwardness
  • weakness in the arm or leg on one side of the body, sudden and severe
  • weakness in the arms, hands, legs, or feet
Incidence not known
  • Black, tarry stools
  • bleeding gums
  • cough
  • dark urine
  • difficulty with swallowing
  • general tiredness and weakness
  • hives
  • itching
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • light-colored stools
  • muscle cramps or spasms
  • muscle pain or stiffness
  • pinpoint red spots on the skin
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • skin rash
  • upper right abdominal or stomach pain
  • yellow eyes and skin

Some of the side effects that can occur with 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:

More common
  • Blindness
  • body aches or pain
  • decreased vision
  • dry cough
  • ear congestion
  • loss of voice
  • nasal congestion
  • runny nose
  • sneezing
  • sore throat
Less common
  • Acid or sour stomach
  • back pain
  • belching
  • difficulty with moving
  • heartburn
  • increased sensitivity to pain
  • increased sensitivity to touch
  • indigestion
  • joint pain
  • lack or loss of strength
  • pain in the knees or legs
  • pain or tenderness around the eyes and cheekbones
  • stomach discomfort or upset
  • swollen joints
  • trouble sleeping
  • weight gain
  • Ankle, knee, or great toe joint pain
  • bloated
  • change or loss of taste
  • depression
  • difficulty having a bowel movement (stool)
  • dry skin
  • excess air or gas in the stomach or intestines
  • full feeling
  • hair loss or thinning of the hair
  • hearing loss
  • increased sensitivity of the skin to sunlight
  • loss of appetite
  • passing gas
  • redness or other discoloration of the skin
  • severe sunburn
  • weight loss

For Healthcare Professionals

Applies to losartan: oral tablet


The most common adverse reactions were upper respiratory infection and dizziness.[Ref]


Common (1% to 10%): Nasal congestion, upper respiratory infection, sinusitis, pharyngitis, cough, sinus disorder
Uncommon (0.1% to 1%): Dyspnea
Frequency not reported: Bronchitis, pharyngeal discomfort, epistaxis, rhinitis, respiratory congestion[Ref]


Common (1% to 10%): Abdominal pain, nausea, diarrhea, dyspepsia
Uncommon (0.1% to 1%): Obstipation, vomiting
Frequency not reported: Constipation, dental pain, dry mouth, flatulence, gastritis[Ref]


Common (1% to 10%): Muscle cramp, back pain, leg pain, myalgia
Frequency not reported: Arm pain, hip pain, joint swelling, knee pain, musculoskeletal pain, shoulder pain, stiffness, arthralgia, arthritis, fibromyalgia, muscle weakness
Postmarketing reports: Rhabdomyolysis[Ref]


Common (1% to 10%): Renal impairment, renal failure, BUN increased, serum creatinine increased[Ref]

Nervous system

Common (1% to 10%): Dizziness, headache, vertigo
Uncommon (0.1% to 1%): Somnolence
Rare (less than 0.1%): Paresthesia, syncope, cerebrovascular accident
Frequency not reported: Ataxia, hypesthesia, memory impairment, migraine, peripheral neuropathy, tremor, taste perversion, tinnitus[Ref]


Common (1% to 10%): Asthenia/fatigue, edema/swelling, chest pain
Frequency not reported: Facial edema, fever, orthostatic effects
Postmarketing reports: Malaise[Ref]


Common (1% to 10%): Hyperkalemia, serum potassium increased, hypoglycemia
Frequency not reported: Anorexia, gout
Postmarketing reports: Hyponatremia[Ref]


Common (1% to 10%): Orthostatic hypotension
Uncommon (0.1% to 1%): Palpitation, angina pectoris
Rare (less than 0.1%): Atrial fibrillation
Frequency not reported: Second degree atrioventricular block, hypotension, myocardial infarction, sinus bradycardia, tachycardia, ventricular tachycardia, ventricular fibrillation, flushing
Postmarketing reports: Vasculitis[Ref]


Common (1% to 10%): Insomnia
Uncommon (0.1% to 1%): Sleep disorder
Frequency not reported: Anxiety, anxiety disorder, confusion, depression, dream abnormality, libido decreased, nervousness, panic disorder[Ref]


Common (1% to 10%): Anemia
Rare (less than 0.1%): Hemolysis
Postmarketing reports: Thrombocytopenia, hemoglobin decreased, hematocrit decreased[Ref]


Uncommon (0.1% to 1%): Urticaria, pruritus, rash
Rare (less than 0.1%): Angioedema, superficial peeling of palms
Frequency not reported: Alopecia, dermatitis, dry skin, ecchymosis, erythema, photosensitivity, sweating
Postmarketing reports: Erythroderma[Ref]


Rare (less than 0.1%): ALT increased
Postmarketing reports: Hepatitis, liver enzymes increased, serum bilirubin increased, pancreatitis, liver function abnormalities[Ref]


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


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


Frequency not reported: Flu-like symptoms
Postmarketing reports: Anaphylactic reactions, hypersensitivity reactions[Ref]


1. Cerner Multum, Inc. "Australian Product Information." O 0

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

3. "Product Information. Cozaar (losartan)." Merck & Co, Inc, West Point, PA.

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