Do not use methadone if you are allergic to it, or if you have:
- breathing problems or severe asthma
- a blockage in your stomach or intestines
To make sure methadone is safe for you, tell your doctor if you have ever had:
- breathing problems, sleep apnea
- brain tumor, a head injury, or seizures
- heart problems, long QT syndrome (in you or a family member)
- alcohol or drug addiction, or mental illness
- urination problems
- problems with your gallbladder, pancreas, or thyroid
Methadone can cause a fatal heart rhythm disorder. If you have a headache with chest pain, severe dizziness, or fast or pounding heartbeats, call your doctor right away. Your doctor may check your heart function during treatment.
If you use opioid medications while pregnant, your baby may become dependent on the drug. This can cause fatal withdrawal symptoms in the baby after birth. Babies born dependent on opioids may require medical care for several weeks.
Do not breastfeed. Methadone can enter the breast milk and cause drowsiness, breathing difficulties, or death in a nursing baby.