Methadone Accord Healthcare (Methadone Hydrochloride)

Methadone is an opioid agonist used in the management of opioid‑related disorders and pain conditions.

• Opioid dependence: suppresses withdrawal symptoms and supports maintenance therapy.
• Chronic pain management: provides analgesia for moderate to severe persistent pain when other opioids are unsuitable.
• Cancer‑related pain: offers palliation for severe pain in oncology patients.

• Methadone acts primarily as a full agonist at the mu‑opioid receptor, producing analgesia and reducing opioid cravings. It also antagonizes NMDA receptors, which may help mitigate opioid tolerance and hyperalgesia. Additionally, methadone inhibits the reuptake of serotonin and norepinephrine, contributing to its analgesic profile.

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

Common Side Effects

• Constipation: reduced bowel motility leading to hard stools.
• Nausea: feeling of queasiness, sometimes with vomiting.
• Drowsiness: increased sleepiness or fatigue.
• Sweating: excessive perspiration unrelated to temperature.
• Dry mouth: reduced salivation causing discomfort.
• Dizziness: sensation of light‑headedness or imbalance.

Serious or Rare Side Effects

• Respiratory depression: slowed or shallow breathing that can be life‑threatening.
• QT interval prolongation: cardiac rhythm disturbance increasing arrhythmia risk.
• Severe hypotension: marked drop in blood pressure causing faintness.
• Adrenal insufficiency: inadequate cortisol production leading to fatigue and weakness.
• Seizures: rare episodes of uncontrolled electrical activity in the brain.

Methadone requires careful monitoring due to its potency and pharmacologic profile.

• Cardiac risk assessment: evaluate QT prolongation potential before initiating therapy.
• Respiratory monitoring: observe for signs of respiratory depression, especially during dose changes.
• Liver function evaluation: adjust dosing in patients with hepatic impairment.
• Elderly caution: start with lower doses and titrate slowly.
• Discontinuation guidance: avoid abrupt cessation to prevent severe withdrawal.
• Store at ambient temperature: keep in the original container, protect from moisture and direct sunlight.

Methadone interacts with several drug classes, necessitating vigilance.

Major Interactions (Avoid)

• Central nervous system depressants: may cause profound sedation or respiratory depression.
• Monoamine oxidase inhibitors (MAOIs): risk of serotonin syndrome and hypertensive crisis.
• QT‑prolonging agents: additive effect on cardiac repolarization increasing arrhythmia risk.

Moderate Interactions (Monitor Closely)

• CYP3A4 inhibitors (e.g., ketoconazole): may raise methadone plasma levels.
• CYP3A4 inducers (e.g., rifampin): may lower methadone concentrations, reducing efficacy.
• Selective serotonin reuptake inhibitors (SSRIs): potential for enhanced serotonergic effects.