KEYTRUDA Side Effects by Likelihood and Severity

COMMON side effects

If experienced, these tend to have a Severe expression i

  • a condition with low thyroid hormone levels
  • anemia
  • a decreased number of lymphocytes in the blood
  • cellulitis

If experienced, these tend to have a Less Severe expression i

  • constipation
  • itching
  • joint pain
  • fever
  • low energy
  • pain
  • taste impairment
  • a skin rash
  • decreased appetite
  • trouble breathing
  • cough
  • nausea
  • diarrhea
  • intense abdominal pain
  • pain in the muscles or bones

INFREQUENT side effects

If experienced, these tend to have a Severe expression i

  • a systemic inflammatory response called sepsis due to an infection with bacteria
  • overactive thyroid gland
  • low amount of sodium in the blood
  • low amount of potassium in the blood
  • decreased blood platelets
  • low levels of a type of white blood cell called neutrophils
  • confusion
  • a heart attack
  • inflammation of the covering of the heart or pericardium
  • pericardial tamponade, a disorder of the heart
  • fluid in the covering of the heart or pericardium
  • supraventricular tachycardia
  • sinus tachycardia, a type of fast heart rate
  • a type of inflammation of the lung called interstitial pneumonitis
  • inflammation of the large intestine
  • high amount of bilirubin in the blood
  • abnormal liver function tests
  • inflammation of the pituitary gland
  • a high alanine transaminase level
  • a high aspartate transaminase level

If experienced, these tend to have a Less Severe expression i

  • a painful condition that affects the nerves in the legs and arms called peripheral neuropathy
  • a common cold
  • urinary tract infection
  • hair loss
  • a condition where portions of the skin lose the natural color called vitiligo
  • backache
  • muscle pain
  • dizziness
  • difficulty sleeping
  • chills
  • fluid retention in the legs, feet, arms or hands
  • temporary redness of face and neck
  • headache
  • a change in voice
  • vomiting
  • generalized weakness
  • a type of bumpy skin rash called a maculopapular rash
  • fast heartbeat

RARE side effects

If experienced, these tend to have a Severe expression i

  • sarcoidosis
  • thyroid gland inflammation
  • diabetes
  • low levels of parathyroid hormone
  • pituitary hormone deficiency
  • decreased function of the adrenal gland
  • a type of blood disorder where the red blood cells burst called hemolytic anemia
  • destruction of red blood cells by body's own antibodies
  • low blood counts due to bone marrow failure
  • encephalitis
  • inflammation of the spinal cord
  • Guillain-Barre syndrome
  • inflammation of the uvea of the eye
  • a clot in the lung
  • atrial fibrillation
  • inflammation of the middle tissue heart muscle
  • allergic reaction causing inflammation of blood vessels
  • inflammation of the blood vessels
  • low blood pressure
  • bleeding
  • pneumonia
  • escape of fluid into the lungs
  • lung failure causing loss of breath
  • liver inflammation resulting from an abnormal immune response
  • scarring of bile ducts called sclerosing cholangitis
  • kidney inflammation
  • kidney failure
  • decreased kidney function
  • bloody urine
  • bullous pemphigoid
  • a skin disorder with blistering and peeling skin called toxic epidermal necrolysis
  • a skin disorder with blistering and peeling skin called Stevens-Johnson syndrome
  • skin rash with sloughing
  • muscle pain and stiffness in the shoulder, neck and pelvis
  • a condition with muscle tissue breakdown called rhabdomyolysis
  • seizures
  • decreased oxygen in the tissues or blood
  • a significant type of allergic reaction called anaphylaxis
  • graft-versus-host disease
  • chronic inflammation of muscles in the body called polymyositis
  • pancreatitis
  • a fistula between two body organs
  • a type of significant allergic skin reaction called DRESS syndrome
  • urosepsis, a bacterial infection originating from the urinary tract
  • histiocytic necrotizing lymphadenitis, a condition with swollen glands in the neck and flu symptoms
  • hemophagocytic lymphohistiocytosis, a condition where the body makes too many activated immune cells

If experienced, these tend to have a Less Severe expression i

  • arthritis
  • muscle weakness
  • muscle inflammation

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Selected from data included with permission and copyrighted by First Databank, Inc. This copyrighted material has been downloaded from a licensed data provider and is not for distribution, except as may be authorized by the applicable terms of use.

CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.