Methadone is used to relieve severe pain in individuals who need to take 24 hour pain medication and in individuals who cannot take other medications. It is also used to prevent the abstinence symptoms in those who are trying to detox from opiate drugs.


What is Methadone?

Methadone is a narcotic. It works by changing the way the brain and nervous system respond to pain. In the case of addiction to opioids, it produces similar effects to drugs and prevents the appearance of withdrawal symptoms in people who have stopped taking them.


How should Methadone be taken?

Methadone can be administered in the form of tablets to be swallowed, soluble tablets, solutions and concentrated solutions. When used as a pain reliever, it should be taken every 8-12 hours. When used as part of a detoxification program, a different dosage is prescribed from case to case. The doctor may change the dose of methadone during treatment; however, the dosage should never be changed without consultation from a doctor. Sudden interruptions may cause symptoms quite similar to those of abstinence.


Side effects associated with Methadone

Methadone can cause serious and dangerous respiratory problems, especially during the first 72 hours of treatment and whenever doses are increased.


Possible side effects of this drug include the following:

  • Weakness
  • Headache
  • Nausea
  • Vomiting
  • Loss of appetite
  • Weight gain
  • Stomach ache
  • Dry mouth
  • Difficulty speaking
  • Sweating
  • Redness
  • Difficulty passing urine
  • Mood swings
  • Vision problems
  • Insomnia
  • Sexual problems
  • Abnormalities of the menstrual cycle


You should immediately contact a doctor if the drug triggers:

  • Convulsions
  • Itch
  • Urticaria
  • Rash
  • Swelling of eyes, face, mouth, tongue or throat
  • Hoarseness
  • Difficulty breathing
  • Difficulty swallowing
  • Strong drowsiness
  • Visual or auditory hallucinations


Contraindications and warnings associated with the use of Methadone

Taking Methadone should never be stopped abruptly, but only under the supervision of a doctor, who will probably proceed by reducing the dosage gradually. Methadone can cause drowsiness and impair the ability to drive or operate hazardous machinery. It can also cause dizziness when standing up. It is recommended to avoid consuming grapefruit and its juice while receiving treatment with Methadone.


Before taking the drug, it is important to inform your doctor:

  • If you have any allergies to the active ingredient, its excipients or any other medication
  • If you are taking any other medicinal products, herbal remedies or supplements. Mentioning in particular: antihistamines, buprenorphine, butorphanol, calcium antagonists, fluvoxamine, drugs against HIV, glaucoma, irritable bowel syndrome, Parkinson's disease, ulcers and urinary disorders, nalbuphine, phenytoin, rifampin, and St. John’s wort
  • If you are taking MAO inhibitors, even if treatment was stopped two weeks earlier
  • If you suffer (or have suffered) from paralytic ileus, gastrointestinal blocks, low blood pressure, Addison's disease, seizures, disorders that cause difficulty in urination or gallbladder disease, as well as pancreatic disease, liver disease, or thyroid or kidney disease
  • If you had previously undergone surgery or have suffered from diseases affecting the bowel transit in the digestive tract
  • If you are pregnant or breastfeeding



It is important to inform surgeons and dentists of any ongoing treatment with Methadone. Methadone can cause constipation, in which case it is necessary to implement appropriate dietary measures for prevention.