Drug Interactions
Your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor or pharmacist first. This drug should not be used with the following medication because very serious interactions may occur: naltrexone. If you are currently using this medication, tell your doctor or pharmacist before starting methadone. Many drugs besides methadone may affect the heart rhythm (QT prolongation), including amiodarone, dofetilide, pimozide, procainamide, quinidine, sotalol, among others. This is not a complete list. Therefore, before using methadone, report all medication you are taking to your doctor or pharmacist. Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: certain medications for pain (opiate partial agonists such as butorphanol, nalbuphine, pentazocine), drugs affecting liver enzymes that remove methadone from your body (such as St. John's wort, certain HIV NNRTIs including efavirenz/nevirapine, HIV protease inhibitors including ritonavir, rifamycins including rifampin, azole antifungals including itraconazole, macrolide antibiotics including erythromycin, certain anti-seizure medicines including phenytoin/carbamazepine/phenobarbital, certain SSRI antidepressants including fluvoxamine/fluoxetine/sertraline), MAO inhibitors (such as furazolidone, isocarboxazid, linezolid, moclobemide, phenelzine, procarbazine, rasagiline, selegiline, tranylcypromine), certain HIV NRTIs (stavudine, zidovudine, didanosine chewable/dispersible buffered tablets or pediatric oral solution). The risk of serious side effects (such as slow/shallow breathing, severe drowsiness/dizziness) may be increased if you use this medication with other products that may also affect breathing or cause drowsiness. Therefore, tell your doctor or pharmacist if you are taking other products such as alcohol, medicine for sleep or anxiety (such as alprazolam, diazepam, zolpidem), muscle relaxants, and psychiatric medicines (such as risperidone, amitriptyline, trazodone). Your medications or doses of your medications may need to be changed. Check the labels on all your medicines (such as cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely. This medication may interfere with certain laboratory tests (including amylase and lipase levels), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug. This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.