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Addiction Treatment Products

Naltrexone 50 mg

This information is intended for U.S. healthcare professionals only.


Naltrexone hydrochloride tablets are indicated in the treatment of alcohol dependence and for the blockade of the effects of exogenously administered opioids.

Naltrexone hydrochloride tablets have not been shown to provide any therapeutic benefit except as part of an appropriate plan of management for the addictions.



Naltrexone has the capacity to cause hepatocellular injury when given in excessive doses.

Naltrexone is contraindicated in acute hepatitis or liver failure, and its use in patients with active liver disease must be carefully considered in light of its hepatotoxic effects.

The margin of separation between the apparently safe dose of naltrexone and the dose causing hepatic injury appears to be only five-fold or less. Naltrexone does not appear to be a hepatotoxin at the recommended doses.

Patients should be warned of the risk of hepatic injury and advised to stop the use of naltrexone and seek medical attention if they experience symptoms of acute hepatitis.


Naltrexone is contraindicated in patients:

  • Receiving opioid analgesics.
  • Currently dependent on opioids, including those currently maintained on opiate agonists [e.g., methadone or LAAM (levo-alpha-acetylmethadol)].
  • In acute opioid withdrawal.
  • Who have failed the naloxone challenge test or who have a positive urine screen for opioids.
  • With a history of sensitivity to naltrexone or any other components of this product. It is not known if there is any cross-sensitivity with naloxone or the phenanthrene containing opioids.
  • With acute hepatitis or liver failure.


  • Unintended Precipitation of Abstinence: To prevent occurrence of an acute abstinence syndrome, or exacerbation of a pre-existing subclinical abstinence syndrome, patients must be opioid-free for a minimum of 7 to 10 days before starting naltrexone. Since the absence of an opioid drug in the urine is often not sufficient proof that a patient is opioid-free, a naloxone challenge should be employed if the prescribing physician feels there is a risk of precipitating a withdrawal reaction following administration of naltrexone.
  • While naltrexone is a potent antagonist with a prolonged pharmacologic effect (24 to 72 hours), the blockade produced by naltrexone is surmountable. Any attempt by a patient to overcome the antagonism by taking opioids is very dangerous and may lead to a fatal overdose. The patient may be in immediate danger of suffering life endangering opioid intoxication (e.g., respiratory arrest, circulatory collapse). Patients should be told of the serious consequences of trying to overcome the opiate blockade.
  • Patients should be aware that they may be more sensitive to lower doses of opioids after naltrexone treatment is discontinued. This could result in potentially life-threatening opioid intoxication (respiratory compromise or arrest, circulatory collapse, etc.).
  • Safe use of naltrexone in rapid opiate detoxification programs has not been established.
  • In an emergency situation in patients receiving fully blocking doses of naltrexone, a suggested plan of management is regional analgesia, conscious sedation with a benzodiazepine, use of non-opioid analgesics or general anesthesia. In a situation requiring opioid analgesia, the amount of opioid required may be greater than usual, and the resulting respiratory depression may be deeper and more prolonged. The patient should be monitored closely by appropriately trained personnel in a setting equipped and staffed for cardiopulmonary resuscitation.
  • Severe opioid withdrawal syndromes precipitated by the accidental ingestion of naltrexone have been reported in opioid-dependent individuals. Symptoms of withdrawal have usually appeared within five minutes of ingestion of naltrexone and have lasted for up to 48 hours. Mental status changes and significant fluid losses from vomiting and diarrhea have occurred. Patients should be closely monitored and therapy with non-opioid medications should be tailored to meet individual requirements. Use of naltrexone does not eliminate or diminish withdrawal symptoms.
  • Caution is recommended when administering the drug to patients with renal impairment or liver disease.
  • The risk of suicide is known to be increased in patients with substance abuse with or without concomitant depression. This risk is not abated by treatment with naltrexone.


In the treatment of alcohol and opioid dependence, common adverse reactions include difficulty sleeping, anxiety, nervousness, abdominal pain/cramps, nausea and/or vomiting, low energy, joint and muscle pain, headache, dizziness and somnolence. Placebo-controlled studies employing up to five-fold higher doses of naltrexone hydrochloride (up to 300 mg per day) than that recommended for use in opiate receptor blockade have shown that naltrexone causes hepatocellular injury in a substantial proportion of patients exposed at higher doses. This is not a complete list of potential adverse events associated with naltrexone hydrochloride. Please see Full Prescribing Information for a complete list.

Description yellow, film coated, cap shape
Generic Name naltrexone hydrochloride tablets, USP
Dosage Strength 50 mg
Rating AB


NDC # Package Size Case Quantity
0406-1170-03 30 12
0406-1170-01 100 12

Code: 10004868
Revised: 8/2019