Methadose Side Effects

Generic name: methadone

Medically reviewed by Drugs.com. Last updated on Sep 4, 2023.

Note: This document contains side effect information about methadone. Some dosage forms listed on this page may not apply to the brand name Methadose.

Applies to methadone: injection solution. Other dosage forms:

• oral solution, oral tablet, oral tablet for suspension

Serious side effects of Methadose

Along with its needed effects, methadone (the active ingredient contained in Methadose) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur while taking methadone:

Incidence not known

• Agitation
• blurred vision
• confusion
• darkening of the skin
• diarrhea
• difficult or troubled breathing
• dizziness
• dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
• fainting
• fever
• irregular heartbeat
• recurrent irregular, fast or slow, or shallow breathing
• loss of appetite
• mental depression
• nausea
• overactive reflexes
• pale or blue lips, fingernails, or skin
• poor coordination
• restlessness
• seizures
• shivering
• skin rash
• sweating
• talking or acting with excitement you cannot control
• trembling or shaking
• twitching
• unusual tiredness or weakness
• vomiting

Other side effects of Methadose

Some side effects of methadone may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Incidence not known

• Bleeding, blistering, burning, coldness, discoloration of the kin, feeling of pressure, hives, infection, inflammation, itching, lumps, numbness, pain, rash, redness, scarring, soreness, stinging, swelling, tenderness, tingling, ulceration, or warmth at the injection site
• difficulty having a bowel movement (stool)
• dry mouth
• headache
• lack or loss of strength
• loss of appetite
• weight loss

For Healthcare Professionals

Applies to methadone: compounding powder, injectable solution, intravenous 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, agitation, confusion, disorientation, dysphoria, euphoria, insomnia, hallucinations, seizures^[Ref]

Cardiovascular

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]

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]

Gastrointestinal

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]

Constipation often persists during chronic administration; nausea, and vomiting appear to be more frequent after oral administration.^[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, congenital oculomotor disorders (nystagmus, strabismus)^[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]

Frequently asked questions

• Which drugs cause opioid-induced constipation?
• How long does opioid withdrawal last?
• How can I get emergency methadone?
• Suboxone vs methadone: What’s the difference?
• How long does methadone withdrawal last?
• Does methadone show up on a drug test?
• Is methadone an opiate blocker?
• What is a methadone clinic / are they free?

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.

Medical Disclaimer