Methadone Hydrochloride Side Effects Center

What Is Methadone?

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.

What Are Side Effects of Methadone?

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.

Dosage for Methadone

Dosing of methadone depends on the age, general condition and medical status of the patient, other medications being taken, and other factors.

What Drugs, Substances, or Supplements Interact with Methadone?

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.

Methadone During Pregnancy and Breastfeeding

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.

Additional Information

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.

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

Opioid medicine can slow or stop your breathing, and death may occur. A person caring for you should give naloxone and/or seek emergency medical attention if you have slow breathing with long pauses, blue colored lips, or if you are hard to wake up.

Call your doctor at once if you have:

• weak or shallow breathing, breathing that stops during sleep;
• severe constipation;
• a light-headed feeling, like you might pass out;
• fast or pounding heartbeats, fluttering in your chest, shortness of breath;
• low cortisol levels--nausea, vomiting, loss of appetite, dizziness, worsening tiredness or weakness; or
• serotonin syndrome--agitation, hallucinations, fever, fast heart rate, muscle stiffness, twitching, loss of coordination, nausea, diarrhea.

Serious breathing problems may be more likely in older adults and people who are debilitated or have wasting syndrome or chronic breathing disorders.

Common side effects may include:

• dizziness, drowsiness;
• nausea, vomiting;
• increased sweating; or
• pain, redness, or swelling where the medicine was injected.

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.