Naltrexone Accord (Naltrexone Hydrochloride)

Naltrexone is an opioid antagonist used in the treatment of dependence syndromes related to alcohol and opioids.

• Alcohol dependence: reduces cravings and helps maintain abstinence.
• Opioid dependence (relapse prevention): blocks opioid receptors to prevent relapse.
• Opioid dependence (maintenance therapy): supports sustained abstinence when combined with psychosocial support.

• Naltrexone acts as a competitive antagonist at the μ‑, κ‑ and δ‑opioid receptors. By binding to these receptors without activating them, it blocks the effects of endogenous opioids and exogenous opioid agonists. This inhibition reduces the rewarding and reinforcing properties of alcohol and opioid substances, thereby decreasing cravings and helping to prevent relapse in dependent individuals. The blockade is dose‑dependent and persists for several hours after dosing, providing continuous receptor antagonism throughout the day.

Naltrexone may be associated with a range of adverse reactions, which are categorized by frequency and severity.

Common Side Effects

• Nausea: mild to moderate stomach upset that may resolve spontaneously.
• Headache: transient cranial discomfort, often relieved with simple analgesics.
• Dizziness: light‑headed sensation, especially when standing quickly.
• Fatigue: feeling unusually tired, may affect daily activities.

Serious or Rare Side Effects

• Hepatotoxicity: elevated liver enzymes or clinically significant liver injury.
• Severe allergic reaction: rash, swelling, or difficulty breathing requiring immediate care.
• Depression or suicidal thoughts: mood changes that necessitate urgent medical evaluation.
• Seizures: rare occurrence, particularly in patients with a prior seizure disorder.

When prescribing Naltrexone Accord, several safety considerations should be observed.

• Liver function monitoring: assess hepatic enzymes before initiating therapy and periodically during treatment.
• Concomitant opioid use: avoid using opioid analgesics as naltrexone blocks their effects and may precipitate withdrawal.
• Alcohol consumption: advise patients to limit alcohol intake and monitor for hepatic effects.
• Pregnancy and lactation: use only if potential benefit justifies potential risk, as safety data are limited.
• Driving and machinery: caution patients about possible dizziness or fatigue that may impair performance.
• Store at ambient temperature: keep below 25 °C in the original packaging, protect from moisture and light.

Naltrexone may interact with several medications; awareness of these interactions helps ensure safe use.

Major Interactions (Avoid)

• Opioid analgesics: naltrexone blocks analgesic effect and can precipitate withdrawal.
• Disulfiram: combined use may increase hepatotoxic risk.
• Methadone or buprenorphine: antagonism may lead to loss of opioid effect and precipitate withdrawal.

Moderate Interactions (Monitor Closely)

• Hepatotoxic drugs (e.g., isoniazid, rifampin): monitor liver function tests.
• CNS depressants (e.g., benzodiazepines): may enhance sedation if dizziness occurs.
• Antidepressants (e.g., SSRIs): observe for mood changes.