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Methadone Hydrochloride

Last reviewed on RxList: 5/24/2017
Methadone Hydrochloride Side Effects Center

Last reviewed on RxList 11/02/2016

Methadone Hydrochloride Tablets (methadone) is a narcotic used as a pain reliever and as part of drug addiction detoxification and maintenance programs. Methadone hydrochloride is available in generic form. Common side effects of methadone hydrochloride include:

  • anxiety,
  • nervousness,
  • restlessness,
  • sleep problems (insomnia),
  • weakness,
  • drowsiness,
  • dry mouth,
  • nausea,
  • vomiting,
  • diarrhea,
  • constipation,
  • loss of appetite,
  • decreased sex drive,
  • impotence, or
  • difficulty having an orgasm.

Tell your doctor if you experience serious side effects of methadone hydrochloride including:

  • shallow breathing,
  • hallucinations,
  • confusion,
  • chest pain,
  • dizziness,
  • fainting,
  • fast or pounding heartbeat,
  • trouble breathing,
  • lightheadedness, or
  • fainting.

Dosing of methadone depends on the age, general condition and medical status of the patient, other medications being taken, and other factors. Methadone may interact with other narcotic pain medications, sedatives, tranquilizers, muscle relaxers, other medicines that can make you sleepy or slow your breathing, diuretics (water pills), antibiotics, heart or blood pressure medications, HIV medicines, MAO inhibitors, rifampin, or seizure medication. Many other medicines may cause serious medical problems if you take them together with methadone. Tell your doctor all prescription and over-the-counter medications and supplements you use. During pregnancy, Methadone should be used only if prescribed. It may be harmful to a fetus. It could also cause addiction or withdrawal symptoms in a newborn if the mother takes methadone during pregnancy. Methadone can pass into breast milk and may harm a nursing baby. Consult your doctor before breastfeeding. Withdrawal symptoms may occur if you suddenly stop using this medication.

Our Methadone Hydrochloride Tablets (methadone) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Methadone Hydrochloride Consumer Information

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have any of these serious side effects:

  • shallow breathing;
  • hallucinations or confusion;
  • chest pain, dizziness, fainting, fast or pounding heartbeat; or
  • trouble breathing, feeling light-headed, or fainting.

Less serious side effects may include:

  • feeling anxious, nervous, or restless;
  • sleep problems (insomnia);
  • feeling weak or drowsy;
  • dry mouth, nausea, vomiting, diarrhea, constipation, loss of appetite; or
  • decreased sex drive, impotence, or difficulty having an orgasm.

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Methadone Hydrochloride (Methadone Tablets)

Methadone Hydrochloride Professional Information

SIDE EFFECTS

The following serious adverse reactions are discussed elsewhere in the labeling:

  • Addiction, Abuse, and Misuse [see WARNINGS AND PRECAUTIONS]
  • Life Threatening Respiratory Depression [see WARNINGS AND PRECAUTIONS]
  • QT Prolongation [see WARNINGS AND PRECAUTIONS]
  • Neonatal Opioid Withdrawal Syndrome [see WARNINGS AND PRECAUTIONS]
  • Interactions with Other CNS Depressants[see WARNINGS AND PRECAUTIONS]
  • Hypotensive Effect [see WARNINGS AND PRECAUTIONS]
  • Gastrointestinal Effects [see WARNINGS AND PRECAUTIONS]
  • Seizures [see WARNINGS AND PRECAUTIONS]

The major hazards of methadone are respiratory depression and, to a lesser degree, systemic hypotension. Respiratory arrest, shock, cardiac arrest, and death have occurred.

The most frequently observed adverse reactions include lightheadedness, dizziness, sedation, nausea, vomiting, and sweating. These effects seem to be more prominent in ambulatory patients and in those who are not suffering severe pain. In such individuals, lower doses are advisable.

Other adverse reactions include the following:

Body as a Whole: asthenia (weakness), edema, headache

Cardiovascular: arrhythmias, bigeminal rhythms, bradycardia, cardiomyopathy, ECG abnormalities, extrasystoles, flushing, heart failure, hypotension, palpitations, phlebitis, QT interval prolongation, syncope, T-wave inversion, tachycardia, torsades de pointes, ventricular fibrillation, ventricular tachycardia

Central Nervous System: agitation, confusion, disorientation, dysphoria, euphoria, insomnia, hallucinations, seizures, visual disturbances

Endocrine: hypogonadism

Gastrointestinal: abdominal pain, anorexia, biliary tract spasm, constipation, dry mouth, glossitis

Hematologic: reversible thrombocytopenia has been described in opioid addicts with chronic hepatitis

Metabolic: hypokalemia, hypomagnesemia, weight gain

Renal: antidiuretic effect, urinary retention or hesitancy

Reproductive: amenorrhea, reduced libido and/or potency, reduced ejaculate volume, reduced seminal vesicle and prostate secretions, decreased sperm motility, abnormalities in sperm morphology

Respiratory: pulmonary edema, respiratory depression

Skin and Subcutaneous Tissue: pruritus, urticaria, other skin rashes, and rarely, hemorrhagic urticaria

Hypersensitivity: Anaphylaxis has been reported with ingredients contained in DOLOPHINE. Advise patients how to recognize such a reaction and when to seek medical attention.

Maintenance on a Stabilized Dose: During prolonged administration of methadone, as in a methadone maintenance treatment program, constipation and sweating often persist and hypogonadism, decreased serum testosterone and reproductive effects are thought to be related to chronic opioid use.

DOLOPHINE for the Detoxification and Maintenance Treatment of Opioid Dependence: During the induction phase of methadone maintenance treatment, patients are being withdrawn from illicit opioids and may have opioid withdrawal symptoms. Monitor patients for signs and symptoms including: lacrimation, rhinorrhea, sneezing, yawning, excessive perspiration, goose-flesh, fever, chilling alternating with flushing, restlessness, irritability, weakness, anxiety, depression, dilated pupils, tremors, tachycardia, abdominal cramps, body aches, involuntary twitching and kicking movements, anorexia, nausea, vomiting, diarrhea, intestinal spasms, and weight loss and consider dose adjustment as indicated.

Read the entire FDA prescribing information for Methadone Hydrochloride (Methadone Tablets)

Related Resources for Methadone Hydrochloride

© Methadone Hydrochloride Patient Information is supplied by Cerner Multum, Inc. and Methadone Hydrochloride Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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