METHADONE HCL Side Effects by Likelihood and Severity

COMMON side effects

If experienced, these tend to have a Severe expression i

  • low blood pressure

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

  • constipation
  • drowsiness
  • fainting
  • dizziness
  • nausea
  • vomiting
  • generalized weakness

INFREQUENT side effects

If experienced, these tend to have a Severe expression i

  • confusion
  • slow heartbeat
  • decreased lung function
  • trouble breathing
  • fast heartbeat

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

  • false sense of well-being
  • a change in vision
  • orthostatic hypotension, a form of low blood pressure
  • dry mouth
  • spasm of a bile duct tract
  • a spasm of the ureter
  • difficulty sleeping
  • excessive sweating
  • decreased appetite
  • headache
  • decreased urine production
  • stomach cramps
  • nervousness

RARE side effects

If experienced, these tend to have a Severe expression i

  • a high prolactin level
  • decreased function of the adrenal gland
  • deficiency of a substance that promotes masculinization
  • low amount of magnesium in the blood
  • low amount of potassium in the blood
  • addiction to a drug
  • serotonin syndrome, a type of disorder with high serotonin levels
  • increased spinal fluid pressure
  • torsades de pointes, a type of abnormal heart rhythm
  • ventricular fibrillation, a heart rhythm disorder
  • complete stoppage of the heart
  • prolonged QT interval on EKG
  • abnormal heart rhythm
  • heart failure
  • fluid in the lungs
  • lung failure causing loss of breath
  • itching
  • hives
  • a condition with muscle tissue breakdown called rhabdomyolysis
  • hallucinations
  • seizures
  • sleep apnea
  • a skin rash
  • a condition where the body is unable to maintain adequate blood flow called shock
  • a significant type of allergic reaction called anaphylaxis
  • accidental falls

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

  • altered interest in having sexual intercourse
  • agitation
  • depression
  • a painful, red or swollen tongue
  • low sperm count
  • the inability to have an erection
  • visible water retention
  • temporary redness of face and neck
  • weight gain
  • heart throbbing or pounding
  • a delay when starting to urinate
  • inflammation of the vein, or phlebitis after infusion
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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.