Methadone comes as a tablet, a dispersible tablet, a liquid, a concentrated solution, or an injection.
Your dose of methadone may range from 2.5 milligrams (mg) to 120 mg daily, depending on your condition. When it’s used to relieve pain, the drug may be taken every eight to 12 hours.
You should take methadone exactly as your doctor prescribes. Your physician might change your dose during the course of your treatment. Do not stop taking methadone without talking to your doctor. Your dose may be decreased gradually to avoid withdrawal symptoms (restlessness, sweating, chills, muscle pain, tearing eyes, runny nose, widened pupils).
Don’t chew or swallow the dispersible tablets before mixing them in a liquid. If your doctor tells you to take only part of a tablet, be sure to break it carefully along the score lines.
Place the tablet in at least four ounces of water or a fruit drink (but avoid grapefruit juice).
You should drink the entire mixture right away. If some tablet residue gets left behind in the cup, you can add a small amount of liquid and drink it.
Methadone carries a black-box warning because it may cause serious or life-threatening breathing problems.
The risk of breathing problems is highest during the first 72 hours of treatment and any time your dose is increased.
You should tell your doctor if you have or have ever had asthma, slowed breathing, chronic obstructive pulmonary disease (COPD), or any other type of lung disease; a head injury; any condition that increases pressure in your brain; or obstructive or central sleep apnea.
Also, you should watch for any signs of breathing problems, including slowed breathing, long pauses between breaths, or shortness of breath.
This medication may also cause a rare heart problem known as a long QT interval. This condition can cause irregular heartbeat, fainting, or sudden death.
You should tell your doctor if you or anyone in your family has or has ever had long QT syndrome.
Also, tell your healthcare provider if you have ever had a slow or irregular heartbeat, heart disease, or low levels of potassium or magnesium in your blood.
Call your doctor right away if you experience a pounding heartbeat, lightheadedness, dizziness, or fainting while taking methadone.
Before taking methadone, you should tell your doctor if you have or have ever had:
Paralytic ileus (a condition where digested food doesn’t move through the intestines)
A blockage in your intestine
An enlarged prostate
Addison’s disease (a condition where the adrenal gland doesn’t work properly)
Thyroid, pancreas, gallbladder, liver, or kidney disease
Tell your physician you are taking methadone before having any type of surgery, including dental procedures.
All medicines have side effects. But many people don’t feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.
Here are some important things to think about:
Usually the benefits of the medicine are more important than any minor side effects.
Side effects may go away after you take the medicine for a while.
If side effects still bother you and you wonder if you should keep taking the medicine, call your doctor. He or she may be able to lower your dose or change your medicine. Do not suddenly quit taking your medicine unless your doctor tells you to.
Call or other emergency services right away if you have:
Swelling of your face, lips, tongue, or throat.
Signs of an overdose, including:
Cold, clammy skin.
Severe nervousness or restlessness.
Severe dizziness, drowsiness, or weakness.