FENTANYL Side Effects by Likelihood and Severity

COMMON side effects

If experienced, these tend to have a Severe expression i

  • hallucinations
  • fever
  • apnea, a breathing interruption
  • trouble breathing
  • an inability to completely empty the bladder
  • abnormal nervous system function affecting alertness

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

  • confusion
  • false sense of well-being
  • dry mouth
  • conditions of excess stomach acid secretion
  • constipation
  • itching
  • drowsiness
  • dizziness
  • difficulty sleeping
  • excessive sweating
  • decreased appetite
  • headache
  • nausea
  • vomiting
  • diarrhea
  • nervousness
  • generalized weakness
  • a sensation of feeling cold
  • anxious feelings

INFREQUENT side effects

If experienced, these tend to have a Severe expression i

  • paranoia
  • depression
  • abnormal heart rhythm
  • low blood pressure
  • a common cold
  • decreased lung function
  • fainting
  • a type of abnormal movement disorder called dyskinesia
  • slurred speech
  • coughing up of blood
  • chest pain
  • unsteady walking

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

  • nightmares
  • agitation
  • throat irritation
  • memory loss
  • low energy
  • flu-like symptoms
  • a reaction at the site of administration
  • a stinging sensation on the skin
  • upper abdominal pain

RARE side effects

If experienced, these tend to have a Severe expression i

  • adrenal gland problems
  • addiction to a drug
  • serotonin syndrome, a type of disorder with high serotonin levels
  • a toxic effect on the central nervous system, which consists of the brain and spinal cord
  • lazy eye
  • high blood pressure
  • slow heartbeat
  • asthma
  • skin rash with sloughing
  • blistering of the skin
  • sleep apnea
  • breathing changes
  • wheezing
  • chest tightness
  • decreased urine production
  • abdominal bloating
  • urinary urgency, or the sudden urge to urinate
  • accidental falls

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

  • blurred vision
  • a change in vision
  • the inability to have an erection
  • hyperesthesia, an increased nerve sensitivity
  • fast heartbeat

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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.