Methadone Oral

Methadone Oral Warning

Methadone has caused very serious (possibly fatal) breathing and heart rhythm problems (QT prolongation in the EKG, torsades de pointes). These problems are more likely to occur when this medication is first started or when the dose is increased. Breathing problems may occur a while after you take your dose (for example, more than 8 hours later). Carefully follow your doctor's directions on how to take the medication. Even if this medication is not working well, do not increase your dose or take this medication more often than prescribed without first consulting your doctor. It may sometimes take 3 to 5 days before you get the full benefit of pain relief from this medication. Seek immediate medical attention if you develop symptoms of breathing and heart rhythm problems, such as slow/shallow breathing, fast/irregular heartbeat, severe dizziness, or fainting.

Methadone Oral Side Effects

See also Warning section.

Nausea, vomiting, constipation, lightheadedness, dizziness, dry mouth, drowsiness, stomach upset, and increased sweating may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

To prevent constipation, maintain a diet adequate in fiber, drink plenty of water, and exercise. Consult your pharmacist for help in selecting a laxative (such as a stimulant type with stool softener).

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 immediately if any of these unlikely but serious side effects occur:

• mental/mood changes (such as agitation, confusion, hallucinations)
• difficulty urinating
• vision changes

Tell your doctor immediately if any of these rare but very serious side effects occur:

• severe stomach/abdominal pain
• change in the amount of urine
• seizures

A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any of the following symptoms of a serious allergic reaction:

• 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.

Call your doctor for medical advice about side effects. In the US, you may report side effects to the Food and Drug Administration (FDA) at 1-800-FDA-1088.

In Canada, you may report side effects to Health Canada at 1-866-234-2345.

Previous Section

Dosage and Storage

Next Section

Drug Interactions