Methadone HCL is used to treat severe ongoing pain (such as due to cancer). Methadone belongs to a class of drugs known as opioid (narcotic) analgesics. It works in the brain to change how your body feels and responds to pain.
Do not use this medication to relieve pain that is mild or that will go away in a few days (such as pain from surgery). This medication is not for occasional (“as needed”) use.
This medication is also used to treat addiction to opioids (such as heroin) as part of an approved treatment program. It helps prevent withdrawal symptoms caused by stopping other opioids.
How to use Methadone HCL
See also Warning section.
Read the Medication Guide provided by your pharmacist before you start using methadone and each time you get a refill. If you have any questions, ask your doctor or pharmacist.
Take this medication by mouth on a regular schedule as directed by your doctor, not as needed for sudden (breakthrough) pain. You may take this drug with or without food. If you have nausea, it may help to take this drug with food. Ask your doctor or pharmacist about other ways to decrease nausea (such as lying down for 1 to 2 hours with as little head movement as possible).
Carefully measure the dose using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose. If your medication comes in an oral dosing syringe, use the syringe to measure the dose. Do not inject the medication. Before taking, mix the dose in at least 1 ounce (30 milliliters) of water or other liquid as directed. Drink all of the mixture right away. Do not prepare a supply in advance.
The dosage is based on your medical condition and response to treatment.
Suddenly stopping this medication may cause withdrawal, especially if you have used it for a long time or in high doses. To prevent withdrawal, your doctor may lower your dose slowly. Tell your doctor or pharmacist right away if you have any withdrawal symptoms such as restlessness, mental/mood changes (including anxiety, trouble sleeping, thoughts of suicide), watering eyes, runny nose, nausea, diarrhea, sweating, muscle aches, or sudden changes in behavior.
When this medication is used for a long time, it may not work as well. Talk with your doctor if this medication stops working well.
Though it helps many people, this medication may sometimes cause addiction. This risk may be higher if you have a substance use disorder (such as overuse of or addiction to drugs/alcohol). Take this medication exactly as prescribed to lower the risk of addiction. Ask your doctor or pharmacist for more details.
Tell your doctor if your condition does not get better or if it gets worse.
See also Warning section.
Nausea, vomiting, constipation, lightheadedness, dizziness, dry mouth, drowsiness, or sweating may occur. Some of these side effects may decrease after you have been using this medication for a while. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.
To prevent constipation, eat dietary fiber, drink enough water, and exercise. You may also need to take a laxative. Ask your pharmacist which type of laxative is right for you.
To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Tell your doctor right away if you have any serious side effects, including: mental/mood changes (such as agitation, confusion, hallucinations), stomach/abdominal pain, difficulty urinating, signs of your adrenal glands not working well (such as loss of appetite, unusual tiredness, weight loss).
Get medical help right away if you have any very serious side effects, including: seizure, severe drowsiness/difficulty waking up.
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.