Metadone Cloridrato Molteni (Methadone Hydrochloride)

Methadone Hydrochloride acts on the opioid system to provide analgesia and to stabilize opioid dependence.

• Severe chronic pain: delivers long‑acting analgesia to reduce persistent pain intensity.
• Opioid dependence maintenance: suppresses withdrawal symptoms and cravings in patients undergoing substitution therapy.
• Palliative care: offers sustained pain relief for patients with advanced disease where other opioids are insufficient.

• Methadone Hydrochloride binds to and activates mu‑opioid receptors in the central nervous system, mimicking the effects of endogenous opioids. This activation inhibits the release of nociceptive neurotransmitters, reducing pain perception, while also attenuating the neurochemical pathways that drive opioid withdrawal and craving, thereby supporting maintenance therapy.

Methadone Hydrochloride may cause a range of adverse reactions, from mild to severe.

Common Side Effects

• Constipation: reduced gastrointestinal motility leading to hard stools.
• Nausea: sensation of queasiness, often transient.
• Drowsiness: increased sleepiness or fatigue.
• Dry mouth: reduced salivary flow causing oral discomfort.
• Sweating: excessive perspiration unrelated to temperature.
• Mood changes: irritability or mild anxiety.

Serious or Rare Side Effects

• Respiratory depression: slowed breathing that can be life‑threatening.
• Cardiac arrhythmia: abnormal heart rhythm, especially QT prolongation.
• Severe hypotension: marked drop in blood pressure causing dizziness.
• Seizures: convulsive episodes, particularly at high doses.
• Allergic reactions: rash, itching, swelling, or anaphylaxis.
• Dependence and abuse: risk of addiction with prolonged use.

Methadone Hydrochloride requires careful monitoring due to its potency and potential for dependence.

• Initiation: start at low doses and titrate slowly under medical supervision.
• Monitoring: regular assessment of respiratory function, cardiac status, and liver function.
• Interactions: avoid concurrent use with other central nervous system depressants.
• Pregnancy: use only if benefits outweigh risks; consult a specialist.
• Storage: Store below 25°C: keep in the original container, protect from moisture and light.

Methadone Hydrochloride can interact with several drug classes, altering its efficacy or safety.

Major Interactions (Avoid)

• Benzodiazepines: combined use may cause profound respiratory depression.
• MAO inhibitors: can precipitate hypertensive crisis or serotonin syndrome.
• QT‑prolonging agents: increase risk of cardiac arrhythmia.

Moderate Interactions (Monitor Closely)

• CYP3A4 inhibitors (e.g., erythromycin): may raise methadone plasma levels.
• CYP3A4 inducers (e.g., rifampin): may reduce methadone effectiveness.
• CNS depressants (e.g., alcohol, antihistamines): enhance sedative effects.