Skip to Content

Methadone Side Effects

Not all side effects for methadone 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 methadone: oral liquid, oral solution, oral tablet, oral tablet for suspension

In addition to its needed effects, some unwanted effects may be caused by methadone. 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 methadone:

Incidence not known
  • Black, tarry stools
  • bleeding gums
  • blood in the urine or stools
  • blurred vision
  • bulging soft spot on the head of an infant
  • change in the ability to see colors, especially blue or yellow
  • changes in skin color
  • chest discomfort or pain
  • confusion
  • convulsions
  • cough
  • coughing that sometimes produces a pink frothy sputum
  • decreased urine output
  • difficult or troubled breathing
  • difficult, fast, noisy breathing, sometimes with wheezing
  • difficulty with swallowing
  • dilated neck veins
  • dizziness
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • dry mouth
  • extreme fatigue
  • fainting
  • fast, slow, or irregular heartbeat
  • headache
  • hives, itching, or skin rash
  • increased sweating
  • increased thirst
  • irregular heartbeat recurrent
  • irregular, fast or slow, or shallow breathing
  • loss of appetite
  • muscle pain or cramps
  • nausea or vomiting
  • numbness or tingling in the hands, feet, or lips
  • pain
  • pale or blue lips, fingernails, or skin
  • pinpoint red spots on the skin
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • seizures
  • sweating
  • swelling of the face, fingers, feet, or lower legs
  • tenderness
  • trouble sleeping
  • trouble urinating
  • unusual bleeding or bruising
  • unusual tiredness or weakness
  • weight gain

Some of the side effects that can occur with methadone 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:

Incidence not known
  • Absent, missed, or irregular menstrual periods
  • anxiety
  • blurred or loss of vision
  • confusion about identity, place, and time
  • constipation
  • decreased interest in sexual intercourse
  • disturbed color perception
  • double vision
  • false or unusual sense of well-being
  • halos around lights
  • inability to have or keep an erection
  • irritability
  • lack or loss of strength
  • loss in sexual ability, desire, drive, or performance
  • night blindness
  • overbright appearance of lights
  • redness, swelling, or soreness of the tongue
  • restlessness
  • stopping of menstrual bleeding
  • tunnel vision
  • weight changes
  • welts

For Healthcare Professionals

Applies to methadone: compounding powder, injectable solution, oral concentrate, oral solution, oral tablet, oral tablet dispersible

Nervous system

Common (1% to 10%): Sedation, drowsiness
Frequency not reported: Headache, seizures, confusion, disorientation, lightheadedness[Ref]

Cardiovascular

Cases of QT interval prolongation and Torsades de pointes have occurred during treatment; these cases appear to be more commonly associated with higher dose treatment (greater than 200 mg per day). There have been some cases in patients receiving lower doses and in these cases contributing factors such as concomitant medications and/or clinical conditions were present. In vivo studies have confirmed this drug effects the QT interval and in vitro studies have shown it inhibits cardiac potassium channels.[Ref]

Common (1% to 10%): Edema
Uncommon (0.1% to 1%): Syncope, flushing, hypotension
Rare (less than 0.1%): Bradycardia, palpitations, QT interval prolongation, Torsades de pointes
Frequency not reported: Arrhythmias, bigeminal rhythms, cardiomyopathy, ECG abnormalities, extrasystoles, heart failure, phlebitis, QT interval prolongation, syncope, T-wave inversion, tachycardia, ventricular fibrillation, ventricular tachycardia[Ref]

Gastrointestinal

Constipation often persists during chronic administration; nausea, and vomiting appear to be more frequent after oral administration.[Ref]

Very common (10% or more): Nausea, vomiting
Common (1% to 10%): Constipation
Uncommon (0.1% to 1%): Dry mouth, glossitis
Frequency not reported: Abdominal pain, anorexia, biliary tract spasm[Ref]

Other

Common (1% to 10%): Vertigo, fatigue
Uncommon (0.1% to 1%): Asthenia, hypothermia[Ref]

Hypersensitivity

Frequency not reported: Anaphylaxis[Ref]

Anaphylaxis has been reported with ingredients contained in methadone products.[Ref]

Psychiatric

Common (1% to 10%): Euphoria, hallucinations
Frequency not reported: Agitation, dysphoria, insomnia, mood changes[Ref]

Endocrine

Uncommon (0.1% to 1%): Galactorrhea, dysmenorrhea, amenorrhea
Frequency not reported: Hypogonadism, decreased serum testosterone, reduced libido and/or potency, reduced ejaculate volume, reduced seminal vesicle and prostate secretions, decreased sperm motility, abnormalities in sperm morphology, gynecomastia, adrenal insufficiency, increased prolactin concentrations[Ref]

Hypogonadism, decreased serum testosterone, and reproductive effects are thought to be related to chronic opioid use.[Ref]

Genitourinary

Uncommon (0.1% to 1%): Urinary retention
Frequency not reported: Urinary hesitancy, ureteric spasm[Ref]

Respiratory

Uncommon (0.1% to 1%): Pulmonary edema, exacerbation of asthma, dry nose, respiratory depression
Frequency not reported: Pulmonary edema[Ref]

Renal

Uncommon (0.1% to 1%): Antidiuretic effect[Ref]

Hematologic

Frequency not reported: Reversible thrombocytopenia, lymphocytosis[Ref]

Reversible thrombocytopenia has been described in opioid addicts with chronic hepatitis.[Ref]

General

The major adverse reaction of this drug is respiratory depression; to a lesser degree, systemic hypotension, respiratory arrest, shock, cardiac arrest, and death have occurred. The most commonly observed adverse reactions include lightheadedness, dizziness, sedation, nausea, vomiting, and sweating.[Ref]

Metabolic

Common (1% to 10%): Weight gain
Frequency not reported: Hypokalemia, hypomagnesemia[Ref]

Ocular

Common (1% to 10%): Miosis, dry eyes
Frequency not reported: Visual disturbances[Ref]

Dermatologic

Common (1% to 10%): Transient rash, sweating
Uncommon (0.1% to 1%): Pruritus, urticaria, other skin rashes
Rare (less than 0.1%): Hemorrhagic urticaria[Ref]

Sweating often persists during chronic administration.[Ref]

Hepatic

Uncommon (0.1% to 1%): Bile duct dyskinesia[Ref]

Local

Frequency not reported: Local tissue reactions (pain, erythema, swelling) particularly with continuous subcutaneous infusion[Ref]

References

1. "Product Information. Diskets (methadone)." Cebert Pharmaceuticals Inc, Birmingham, AL.

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

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

4. "Product Information. Dolophine (methadone)." Lilly, Eli and Company, Indianapolis, IN.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. Drugs.com does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.

Hide