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Side Effects of Methadone (Dolophine, Methadose)


Side Effects of Methadone (Dolophine)

Methadone, available under the brand Dolophine, is a prescription medicine and its chemical composition and mechanism of action is similar to morphine. It is used to treat severe pain when other pain medications have failed. It is also used to treat drug addiction, typically to heroin. Dolophine has a high risk of dependence and addiction and considered a federally controlled substance (CII). It has the potential of being abused by people who misuse prescription medicines or street drugs.

Warnings Before Taking Dolophine

As with all opioids (narcotics), there are some safety considerations with Dolophine. It can slow or stop your breathing and lead to respiratory depression. Risk of potentially fatal respiratory depression is highest when starting Dolophine or when its dose is increased and can even occur at recommended doses (Dolphine label reported by the FDA).


Do not take Dolophine if you have an allergy or allergies to it have asthma or other lung problems, have a bowel blockage or narrowing of the intestines, or are taking a monoamine oxidase Inhibitor (MAOI), which is a type of antidepressant medication.

Common Side Effects

The Dolophine label reported by the FDA outlines the common side effects of Dolphine:


  • Constipation
  • Abdominal pain
  • Nausea and vomitting
  • Sleepiness
  • Tiredness
  • Dizziness
  • Headache

Drug Interactions

Drinking alcohol, using prescription or over-the-counter (OTC) medicines containing alcohol combined with Dolophine should be avoided as it may cause overdose and death.


Medicines used for alcohol or other substance abuse or dependence, cancer, high blood pressure, HIV,constipation, depression or other mental or mood problems, irregular heartbeat or other heart complications, immune system suppression, Huntington disease, infections, hepatitis c, nausea or vomiting, pain, Parkinson disease, reflux or other stomach problems, seizures, sleeping problems, or multivitamin products, and herbal or dietary supplements may interact with Dolophine.

About Pharmacogenetic Testing

The pharmacogenetics of Dolophine is similar to morphine’s with it being extensively metabolized in the liver, according to PharmGKB. The genetic polymorphisms primarily involved are in the cytochrome P450 enzymes and are CYP3A4, CYP2B6, and CYP2C19. Other ones involved are CYP2D6 and CYP2C9.

Know Your Risk with the Rxight® Genetic Test

Rxight® genetic testing sequences a panel of genes and their alleles to analyze inter-individual differences in pharmacogenetic response to Dolphine, along with hundreds of other common pharmaceutical agents. Specifically Rxight® allows individuals and their prescribers to know if methadone is “red-flagged” for them as a medication which could result in dangerous and potentially life-threatening reactions.


To learn more about Rxight® or adverse drug reactions, call us at 1-888-888-1932 or email us at support@Rxight.com.


Contributors to this Article:
Michael Sapko, MD, PhD; and Deborah Kallick, PhD, Medicinal Chemistry

Read more about Rxight® Drug Sensitivity Testing