Naltrexone is an opioid antagonist receptor used in the treatment of opioid and alcohol dependence. It is marketed under the trade names Depade and Revia, and in its generic form as naltrexone hydrochloride and hydrochloride salt. In the US it is also marketed under the trade name Vivitrol.
While Naltrexone has been shown to be effective as an integral part of the treatment of alcoholism and narcotic addiction, it does not come without a range of side effects that can vary from mild to severe depending on dosage, period of use and the individual user.
Common side effects of Naltrexone include emotional changes such as irritability, anxiety and restlessness. The user may feel light headed and prone to fainting, or may develop increased thirst, weakness and fatigue, bone and muscle pains, insomnia or disturbed sleep, reduced sex drive, impotence or difficulty in achieving an orgasm. Other side effects may not be reported, but users should be vigilant for the appearance of any physical changes and report them to their doctor.
In the case of serious side effects the use of Naltrexone should be immediately discontinued and emergency medical attention should be sought. Users should watch out for severe effects including blurred vision, hallucinations, confusion, thoughts of self harm or suicide, increased heart rate, tinnitus or ear pain, difficulty breathing, skin rashes or itching. Naltrexone users should not drive or operate heavy machinery.
In rare cases the use of Naltrexone has caused similar symptoms to those of opioid withdrawal, manifesting with nausea, abdominal cramps, muscle and joint pain, breathing difficulties, myalgia, depression and restlessness. These symptoms may be indistinguishable from opioid withdrawal, especially when the patient is being weaned from opioids.
In a small number of users Naltrexone may cause damage to the liver. A doctor may wish to test liver function before prescribing the drug, along with regular follow up tests to ensure normal liver function continues.
Up to 15% of Naltrexone users report experiencing depression during use. 1% report suicidal thoughts, and a smaller number have attempted suicide while using the drug. A small number or users report nightmares, hallucinations, euphoria, delirium and decreased libido.
In more than 10% of cases users of Naltrexone have reported headaches, anxiety, low energy and insomnia, while fewer than 10% report loss of appetite, irritability, increased energy and dizziness. In rare cases users have complained of confusion, disorientation, uncontrolled muscular movements, excessive tiredness and weakness.
Patients using Naltrexone may be of the belief that they are immune to the effects of opioids, as Naltrexone works to block opioid receptors. In fact, even on Naltrexone the patient will experience the effects of opioids, though the effect will be reduced. As such users may be more at risk of opioid overdose due to the fact that a larger dose will be required to achieve noticeable effects. Users of Naltrexone should be closely monitored for relapse, especially in cases in which the patient continues to receive medications containing opioids.
Naltrexone blocks the effect of opioids to the degree that medications containing opioids may no longer be effective. Patients treated for common Naltrexone side effects may not respond to opioid based medications used to treat coughs, nausea and rashes caused by Naltrexone.
Naltrexone by itself does not treat alcohol or narcotic addiction, but simply helps block the effects of alcohol and narcotics as part of a complete drug and alcohol treatment program. Nor does Naltrexone treat the symptoms of drug and narcotic withdrawal.
It is important to note that medications designed for the purpose of alleviating the symptoms of withdrawal may be ineffective when used in conjunction with Naltrexone.
Naltrexone is occasionally used as part of a non-FDA approved treatment known as rapid opioid detoxification. The patient is placed under general anesthesia and implanted with Naltrexone in the abdomen. The purpose of this is to keep the patient sedated throughout the detoxification process, alleviating the withdrawal symptoms and allowing the patient to emerge from sedation clear of opioid withdrawal.
While this procedure may help reduce the side effects of both opioid withdrawal and Naltrexone (as the dosage is reduced once the patient regains consciousness) it does carry the risks associated with general anesthesia.