Methadone

1. Introduction

Methadone is a synthetic opioid medication used for pain management and as part of a maintenance programme for opioid use disorder (OUD). It acts on the central nervous system by binding to opioid receptors, providing analgesia and suppressing withdrawal symptoms in individuals dependent on opioids. Methadone is classified as a controlled substance due to its potential for misuse.

2. Indications

  • Chronic pain: For moderate to severe pain that requires continuous, long-term opioid treatment.
  • Opioid use disorder (OUD): Maintenance therapy or detoxification in individuals dependent on opioids.

3. Dosage

For Chronic Pain (Adults):

  • Initial dose: 2.5–10 mg every 8–12 hours.
  • Adjust dosage as needed based on response and tolerance.

For Opioid Use Disorder (Adults):

  • Initial dose: 20–30 mg once daily, with careful titration up to 60–120 mg/day for maintenance therapy.

For Elderly or Debilitated Patients:

  • Lower initial doses (e.g., 2.5 mg) are recommended to minimise the risk of respiratory depression.

4. Administration

  • Methadone tablets or liquid should be taken with water, with or without food.
  • Dose adjustments should be made cautiously due to the long half-life of methadone (24–36 hours).
  • Avoid sudden discontinuation; taper the dose to reduce withdrawal symptoms.

5. Forms Available

  • Tablets: 5 mg, 10 mg, 40 mg (dispersible)
  • Oral solution: 1 mg/mL, 10 mg/mL
  • Injectable: 10 mg/mL

6. Side Effects

6.1 Common Side Effects:

  • Drowsiness
  • Nausea and vomiting
  • Constipation
  • Sweating
  • Dry mouth

6.2 Less Common Side Effects:

  • Dizziness
  • Hypotension
  • Rash or itching

6.3 Rare but Serious Side Effects:

  • Respiratory depression
  • QT prolongation (arrhythmias, torsades de pointes)
  • Severe allergic reactions (anaphylaxis)
  • Dependence or misuse

7. Warnings

  • Respiratory Depression: Methadone can cause life-threatening respiratory depression, particularly during initiation or dose adjustments.
  • QT Prolongation: Monitor patients for cardiac arrhythmias, especially those with a history of heart disease or on other QT-prolonging medications.
  • Risk of Misuse: Methadone has a high potential for abuse and addiction.
  • Avoid use with alcohol or sedatives due to increased risk of sedation and respiratory depression.

8. Precautions

  • Caution in patients with liver or kidney disease, respiratory conditions, or a history of substance abuse.
  • Monitor for signs of overdose, including drowsiness, confusion, or difficulty breathing.
  • Methadone should only be prescribed and managed by experienced healthcare providers.

9. Interactions

  • CNS Depressants (e.g., benzodiazepines, alcohol): Increased risk of respiratory depression and sedation.
  • QT-Prolonging Drugs (e.g., amiodarone, erythromycin): Increased risk of arrhythmias.
  • Enzyme Inducers (e.g., rifampin, phenytoin): May reduce methadone levels, decreasing efficacy.
  • Enzyme Inhibitors (e.g., fluconazole, ciprofloxacin): May increase methadone levels, raising the risk of toxicity.

10. Monitoring Parameters

  • Monitor respiratory rate, sedation level, and pain relief.
  • Perform ECGs at baseline and periodically to check for QT prolongation.
  • Assess liver function and signs of opioid misuse or withdrawal symptoms.

11. Use in Children

  • Methadone is not typically recommended for children except in highly specialised cases, such as neonatal abstinence syndrome, under strict medical supervision.

12. Use in Pregnancy

  • Methadone is commonly used in pregnant women with opioid use disorder as part of a maintenance programme, as it reduces the risk of withdrawal and relapse.
  • Neonatal abstinence syndrome may occur and should be managed post-delivery.

13. Use in Elderly

  • Start with low doses due to increased sensitivity to methadone and a higher risk of respiratory depression. Monitor closely for adverse effects.

14. Use in Kidney Disease

  • Methadone is not significantly removed by dialysis, but dose adjustments may be needed in severe renal impairment. Monitor closely for toxicity.

15. Use in Liver Disease

  • Use with caution in mild to moderate liver impairment due to methadone’s metabolism by the liver. Avoid in severe hepatic failure.

16. Patient Counselling Points

  • Take methadone exactly as prescribed; do not share it with others.
  • Avoid alcohol and sedatives while on methadone.
  • Do not stop methadone suddenly without consulting your doctor to avoid withdrawal symptoms.
  • Report any unusual symptoms, such as chest pain, dizziness, or difficulty breathing, immediately.
  • Keep methadone in a safe place, out of reach of children and others, to prevent misuse.

17. Table of Brand Names, Manufacturer, and Prices in USD

Brand NameManufacturerStrength/Dosage FormPrice (USD)
MethadoseMallinckrodt10 mg/mL Oral Solution$40 (30 mL)
DisketsEli Lilly40 mg Dispersible Tablet$50 (30 tablets)
DolophineRoxane Laboratories10 mg Tablet$25 (30 tablets)

18. 15 FAQs (Frequently Asked Questions)

1. What is Methadone?
Methadone is a synthetic opioid used for pain management and the treatment of opioid use disorder.

2. How does Methadone work?
It binds to opioid receptors in the brain, reducing pain and withdrawal symptoms in individuals dependent on opioids.

3. What is the recommended dosage of Methadone?
Dosage varies depending on the indication. For pain, start with 2.5–10 mg every 8–12 hours. For opioid use disorder, begin with 20–30 mg daily.

4. Can Methadone be taken during pregnancy?
Yes, it is used as part of maintenance therapy in pregnant women with opioid use disorder.

5. Can Methadone be used while breastfeeding?
Yes, but monitor the infant for sedation or respiratory depression.

6. What are the common side effects of Methadone?
Drowsiness, nausea, constipation, and sweating are common side effects.

7. Are there serious risks associated with Methadone?
Yes, serious risks include respiratory depression, QT prolongation, and dependence.

8. What should I do if I miss a dose?
Take the missed dose as soon as possible unless it is close to the next dose. Do not double the dose.

9. What happens if I overdose on Methadone?
Overdose symptoms include severe drowsiness, difficulty breathing, and loss of consciousness. Seek emergency medical help immediately.

10. Can Methadone interact with other medicines?
Yes, interactions with CNS depressants, QT-prolonging drugs, and enzyme inhibitors/inducers can occur.

11. Is Methadone safe for children?
Methadone is rarely used in children and only under specialised medical supervision.

12. Is Methadone safe for elderly patients?
Yes, but lower doses and close monitoring are required.

13. How should Methadone be stored?
Store at room temperature in a secure place out of reach of children.

14. Do I need a prescription for Methadone?
Yes, Methadone is a controlled substance and requires a prescription.

15. Can Methadone be taken with alcohol or specific foods?
No, avoid alcohol and consult your doctor about food interactions.