Metadon Dak (Methadone Hydrochloride)

• Methadone Hydrochloride is used in opioid‑related disorders and severe pain management.
• Opioid dependence: stabilizes patients, reduces withdrawal symptoms and cravings during maintenance therapy.
• Chronic pain: provides long‑acting analgesia for severe, persistent pain unresponsive to other opioids.
• Substance use disorder: supports long‑term substitution treatment to improve functional outcomes.

• Methadone Hydrochloride acts as a full agonist at the μ‑opioid receptor, producing analgesia and suppressing withdrawal by activating the same pathways as endogenous opioids. It also exhibits N‑methyl‑D‑aspartate (NMDA) receptor antagonism, which may reduce opioid tolerance and hyperalgesia. The drug is metabolized primarily by hepatic CYP3A4, CYP2B6 and CYP2D6 enzymes, influencing its plasma concentrations and duration of action. These actions together provide both analgesic and anti‑withdrawal effects.

Methadone Hydrochloride may cause a range of adverse reactions, varying in frequency and severity.

Common Side Effects

• Constipation
• Drowsiness or sedation
• Nausea or vomiting
• Sweating
• Dry mouth

Serious or Rare Side Effects

• Respiratory depression, especially with high doses or concomitant CNS depressants
• QT interval prolongation leading to cardiac arrhythmias
• Severe hypotension or shock
• Allergic reactions such as rash, angioedema, or anaphylaxis

When prescribing Methadone Hydrochloride, clinicians should observe several safety precautions.

• Assess opioid tolerance: confirm patient has prior opioid exposure before initiating therapy.
• Monitor respiratory function: observe for signs of respiratory depression, especially during dose adjustments.
• Avoid abrupt discontinuation: taper the dose gradually to prevent withdrawal syndrome.
• Use caution in hepatic impairment: dose may need reduction in patients with liver disease.
• Evaluate cardiac risk: screen for QT prolongation and correct electrolyte abnormalities.
• Store at room temperature: keep in the original container, protect from moisture and light.

Methadone Hydrochloride interacts with several medications that can alter its effects or increase toxicity.

Major Interactions (Avoid)

• CNS depressants (e.g., benzodiazepines, barbiturates): may cause profound respiratory depression.
• Monoamine oxidase inhibitors (MAOIs): risk of serotonin syndrome and hypertensive crisis.
• Strong CYP3A4 inhibitors (e.g., ketoconazole, erythromycin): increase methadone plasma levels.
• QT‑prolonging drugs (e.g., haloperidol, sotalol): additive risk of cardiac arrhythmias.
• Alcohol: potentiates sedative effects and respiratory depression.

Moderate Interactions (Monitor Closely)

• CYP3A4 inducers (e.g., rifampin, carbamazepine): may reduce methadone concentrations.
• Other opioids: may enhance opioid effects and increase overdose risk.
• Certain antidepressants (e.g., SSRIs, SNRIs): can affect methadone metabolism.
• Antihistamines: may increase sedation.
• NSAIDs: combined use may increase risk of gastrointestinal bleeding.