Methadose Side Effects

Generic name: methadone

Medically reviewed by Drugs.com. Last updated on Mar 19, 2024.

Note: This document provides detailed information about Methadose Side Effects associated with methadone. Some dosage forms listed on this page may not apply specifically to the brand name Methadose.

Applies to methadone: injection solution.

Other dosage forms:

• oral solution, oral tablet, oral tablet for suspension

Precautions

It is very important that your doctor check your progress while you are using this medicine. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to receive it.

Do not use this medicine if you are using or have used an MAO inhibitor within the past 14 days.

This medicine may cause serious allergic reactions, including anaphylaxis. Anaphylaxis can be life-threatening and requires immediate medical attention. Call your doctor right away if you have a rash, itching, trouble breathing, trouble swallowing, or any swelling of your hands, face, or mouth while you are using this medicine.

This medicine will add to the effects of alcohol and other central nervous system (CNS) depressants. CNS depressants are medicines that slow down the nervous system, which may cause drowsiness or make you less alert. Some examples of CNS depressants are antihistamines or medicine for allergies or colds, sedatives, tranquilizers, or sleeping medicine, other prescription pain medicine or narcotics, medicine for anxiety or benzodiazepines, medicine for seizures or barbiturates, muscle relaxants, or anesthetics (numbing medicines), including some dental anesthetics. This effect may last for a few days after you stop using this medicine. Check with your doctor before taking any of the other medicines listed above while you are using this medicine.

Do not use more of this medicine or use it more often than your doctor tells you to. This can be life-threatening. Symptoms of an overdose include extreme dizziness or weakness, trouble breathing, slow heartbeat, seizures, and cold, clammy skin. Call your doctor right away if you notice these symptoms.

This medicine may cause sleep-related breathing problems (eg, sleep apnea, sleep-related hypoxemia). Your doctor may decrease your dose if you have sleep apnea (stop breathing for short periods during sleep) while using this medicine.

Contact your doctor right away if you have any changes to your heart rhythm. You might feel dizzy or faint, or you might have a fast, pounding, or uneven heartbeat. Make sure your doctor knows if you or anyone in your family has ever had a heart rhythm problem such as QT prolongation.

Using this medicine while you are pregnant may cause neonatal withdrawal syndrome in your newborn child. Tell your doctor right away if your baby has an abnormal sleep pattern, diarrhea, a high-pitched cry, irritability, shakiness or tremors, weight loss, vomiting, or fails to gain weight.

Check with your doctor right away if you have anxiety, restlessness, a fast heartbeat, fever, sweating, muscle spasms, twitching, nausea, vomiting, diarrhea, or see or hear things that are not there. These may be symptoms of a serious condition called serotonin syndrome. Your risk may be higher if you also take certain other medicines that affect serotonin levels in your body.

This medicine may be habit-forming (causing mental or physical dependence). If you feel that the medicine is not working as well, do not use more than your prescribed dose. Call your doctor for instructions.

Using narcotics for a long time can cause severe constipation. To prevent this, your doctor may direct you to take laxatives, drink a lot of fluids, or increase the amount of fiber in your diet. Be sure to follow the directions carefully, because continuing constipation can lead to more serious problems.

If you have been using this medicine regularly for several weeks or more, do not suddenly stop using it without first checking with your doctor. You may be directed to gradually reduce the amount you are using before stopping treatment completely, or to take another narcotic for a while, to lessen the chance of withdrawal side effects.

Dizziness, lightheadedness, or fainting may occur when you get up suddenly from a lying or sitting position. Getting up slowly may help lessen this problem. Also, lying down for a while may relieve dizziness or lightheadedness.

This medicine may make you dizzy, drowsy, or lightheaded. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous until you know how this medicine affects you.

Before you have any medical tests, tell the medical doctor in charge that you are using this medicine. The results of some tests may be affected by this medicine.

Using too much of this medicine may cause infertility (unable to have children). Talk with your doctor before using this medicine if you plan to have children.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal (eg, St. John's wort) or vitamin supplements.

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:

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:

See also:

For healthcare professionals

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

General adverse events

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]

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]

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]

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

Methadose side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer