Methadone (By injection)

Methadone (METH-a-done)

Treats moderate to severe pain and narcotic drug addiction in patients who cannot take oral medicines.

Brand Name(s):

When This Medicine Should Not Be Used:

How to Use This Medicine:

Injectable

• A nurse or other health provider will give you this medicine.
• Your doctor will prescribe your exact dose and tell you how often it should be given. This medicine is given as a shot under your skin, into a muscle, or into a vein.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

• Some medicines can affect how methadone works. Tell your doctor if you are using any of the following:
  • Carbamazepine, cyclobenzaprine, desipramine, didanosine, erythromycin, fluconazole, fluvoxamine, ketoconazole, metaxalone, mirtazapine, phenobarbital, phenytoin, rifampin, ritonavir, sertraline, stavudine, St John's wort, telaprevir, tramadol, trazodone, voriconazole, or zidovudine
  • Blood pressure medicine
  • Diuretic (water pill)
  • Hormone medicines
  • Laxatives (stool softeners)
  • MAO inhibitor (MAOI) within the past 14 days
  • Medicine to treat depression, anxiety, or mental health illness
  • Medicine to treat heart rhythm problems
  • Medicine to treat HIV or AIDS
  • Phenothiazine medicine
  • Steroid medicine
  • Triptan medicine to treat migraine headaches
• Do not drink alcohol while you are using this medicine.
• Tell your doctor if you use anything else that makes you sleepy. Some examples are allergy medicine, narcotic pain medicine, and alcohol. Tell your doctor if you are also using buprenorphine, butorphanol, nalbuphine, pentazocine, a benzodiazepine, or a muscle relaxer.

Warnings While Using This Medicine:

• Tell your doctor if you are pregnant or breastfeeding, or if you have kidney disease, liver disease, heart disease, heart rhythm problems (including long QT syndrome), breathing or lung problems (including asthma, COPD, sleep apnea), gallbladder problems, low magnesium or potassium in the blood, pancreas problems, stomach or bowel problems, thyroid problems, or trouble urinating. Tell your doctor if you also have a history of head injury, brain tumors, seizures, depression, or alcohol or drug addiction.
• This medicine may cause the following problems:
  • High risk of overdose, which can lead to death
  • Respiratory depression (serious breathing problem that can be life-threatening)
  • Sleep-related breathing problems (including sleep apnea, sleep-related hypoxemia)
  • Heart rhythm problems
  • Serotonin syndrome (when used with certain medicines)
• This medicine can be habit-forming. Do not use more than your prescribed dose. Call your doctor if you think your medicine is not working.
• Do not stop using this medicine suddenly. Your doctor will need to slowly decrease your dose before you stop it completely.
• This medicine may make you dizzy or drowsy. Do not drive or do anything else that could be dangerous until you know how this medicine affects you. Sit or lie down if you feel dizzy. Stand up carefully.
• This medicine may cause constipation, especially with long-term use. Ask your doctor if you should use a laxative to prevent and treat constipation.
• Tell any doctor or dentist who treats you that you are using this medicine. This medicine may affect certain medical test results.
• This medicine could cause infertility. Talk with your doctor before using this medicine if you plan to have children.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

• Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
• Anxiety, restlessness, fever, muscle spasms, twitching, diarrhea, seeing or hearing things that are not there
• Blue lips, fingernails, or skin
• Extreme dizziness or weakness, shallow breathing, slow or uneven heartbeat, sweating, seizures, cold or clammy skin
• Fast, pounding, or uneven heartbeat
• Severe confusion, lightheadedness, dizziness, fainting
• Severe constipation, stomach pain, nausea, or vomiting
• Trouble breathing or slow breathing

If you notice these less serious side effects, talk with your doctor:

• Mild constipation, nausea, or vomiting
• Mild sleepiness or tiredness
• Pain, itching, burning, swelling, or a lump under your skin where the needle is placed

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 12/4/2023