What is low-dose naltrexone (LDN) and why is it important?
Naltrexone was approved by the FDA in 1984 in a 50mg dose for the purpose of helping heroin or opium addicts, by blocking the effect of such drugs. In technical terms, it is an opioid antagonist. By blocking opioid receptors, naltrexone also blocks the reception of the opioid hormones (endorphins) that our brain and adrenal glands produce - beta-endorphin and metenkephalin. Many body tissues have receptors for the endorphins, including virtually every cell of the body's immune system.
In 1985, Dr. Bernard Bihari discovered the effects of a much smaller dose of naltrexone (approximately 3mg once a day) on the body's immune system. He found that this low dose, taken at bedtime, was able to enhance a patient's response to infection by HIV, the virus that causes AIDS. Subsequently, Dr. Bihari found that patients in his practice with cancer (such as lymphoma or pancreatic cancer) could benefit from LDN. In addition, people who had autoimmune disease (such as lupus) often showed prompt control of disease activity while taking LDN.
How does LDN work? According to Dr. Bihari's information, the brief blockade of opioid (endorphin) receptors that is caused by taking LDN at bedtime each night is believed to produce a prolonged up-regulation of vital elements of the immune system by causing an increase in endorphin production. Normal volunteers who have taken LDN in this fashion have been found to have much higher levels of beta-endorphins circulating in their blood in the following days. It is believed that the endorphins act to increase natural killer cells and other healthy immune defenses against cancer
What diseases has it been useful for? Some diseases for which LDN has been used:
Are there any side effects or cautionary warnings? Naltrexone in these low doses (LDN) has virtually no side effects. Occasionally, during the first week's use, patients may complain of some difficulty sleeping. This rarely persists after the first week. Should it do so, dosage can be reduced to 1.5mg nightly.
Cautionary warnings: Because naltrexone blocks opioid receptors throughout the body for several hours, people using narcotic medication (such as codeine or morphine) should not take naltrexone simultaneously. It should probably not be taken during pregnancy.
Full-dose naltrexone (50mg) carries a caution against its use in those with liver disease. This warning was placed because of adverse liver effects that were found in experiments involving 300mg daily. The 50mg dose does not apparently produce impairment of liver function nor, of course, does the much smaller 3mg dose.
When will the low-dose use of naltrexone become FDA approved? The FDA approved naltrexone at the 50mg dosage in 1984. LDN (the 3mg dosage) has not yet been submitted for approval because it is highly unlikely that any drug company would spend the money to obtain approval for the special use of a drug whose patent has expired. Be assured, the compounded form of naltrexone (LDN) is made with FDA approved chemicals.
All physicians understand that appropriate off-label use of an already FDA-approved medication such as naltrexone is perfectly ethical and legal. Naltrexone itself has already passed toxicity studies.