A Randomized Placebo-Controlled, Crossover-Design Study of the Effects of Low Dose Naltrexone

Immunomodulatory and immunosuppressive therapies are known to modify the course of the disease. Interferon beta-1a, interferon beta-1b and glatiramer acetate are immunomodulators whereas mitoxantrone and natalizumab are immunosuppressants The disease modifying therapies decrease the frequency of relapses and are associated with improved neurological outcomes relative to placebo. However, these medications are only partially effective, are expensive, require either frequent self injections or intravenous infusion and have significant side effects. None are proven in the progressive forms of MS and none of alleviate the symptoms associated with MS. Endogenous Opioid peptides and Naltrexone: Low dose naltrexone (LDN) is proposed to adjust the level of endorphins in the body thereby enhancing immune function and is anecdotally beneficial in MS. LDN is inexpensive, easily administered (one capsule a day at bedtime), and virtually has no serious side effect (during the first weeks of LDN use, some patients complain of some difficulty sleeping, that rarely persists after the first week). Although use of LDN is popular within the MS community efficacy is not proven because clinical trials have not been performed. Naltrexone, is an opioid antagonist approved by the FDA in 1984 in a 50mg dose for the treatment of opioid and alcohol abuse. By blocking opioid receptors, naltrexone also blocks reception of the endogenous opioid peptides: beta-endorphin, metenkephalin and dynorphin. Virtually every cell of the immune system has receptor for these mediators. These peptides regulate a wide range of biological activities, including immune responses through interaction with G-protein coupled transmembrane opioid receptors. In 1985, Bernard Bihari, MD, described the effects of low dose Naltrexone (1.5-4.5 mg Naltrexone) on the body's immune system. He discovered that people with HIV had less than twenty percent of the normal level of endorphins. He began looking for ways to raise endorphin without blocking its receptors and found that 1.75-4.5 mg Naltrexone (Low Dose Naltrexone, LDN) at bed time raises the endorphin level up to 100 to 300 percent during the night. Dr. Bihari has reported beneficial effects of LDN on a variety of diseases such as cancers (e.g. Multiple Myeloma, Lymphoma, Hodgkin's disease, breast cancer, GI cancers, non small cell cancer of lung, malignant melanoma, neuroblastoma, ovarian cancer, prostate cancer, renal cell carcinoma, and uterine cancer), amyotrophic lateral sclerosis, Alzheimer's disease, Behçet's disease, celiac disease, chronic fatigue syndrome, Crohn's disease, emphysema, fibromyalgia, HIV/AIDS, Irritable bowel syndrome, Parkinson's disease, pemphigoid, psoriasis, multiple sclerosis, rheumatoid arthritis, systemic Lupus erythematosus, ulcerative colitis and Wegner's granulomatosis . Despite these anecdotal claims there are no published studies demonstrating efficacy of LDN in any disease state. Because of its low cost and ease of administration and anecdotal reports of efficacy LDN has gained a significant gross-roots following among patients and doctors. There are some striking reports about beneficial effects of LDN on relapse reduction and disability and in general patients treated with LDN report improvements in a sense of well being, fatigue, as well as bowel, bladder and sexual function. Immunological Mechanisms Involved in MS and effects of LDN β-endorphin is an opioid peptide, synthesized by cells of the central nervous system (arcuate nucleus) and immune system (lymphocytes, thymocytes, monocytes and splenocytes). This peptide is decreased in concentration in peripheral blood mononuclear cells (PBMC) of MS patients, with the lowest concentrations linked to the progressive forms of the disease. Furthermore increased concentrations of β-endorphin are found during interferon beta treatment and following clinical relapses. In the animal model of MS, experimental autoimmune encephalitis, β-endorphin blockade worsens disability. Lesions in MS may be the result of oligodendroglial apoptosis and microglial activation rather than neuroinflammatory processes. Activated microglia secrete proinflammatory and neurotoxic factors (nitric oxide and peroxynitrites) that could cause neurodegeneration. In theory, inhibition of microglia would be protective in MS. Naltrexone, is capable of reducing microglial cytokine (IL-1β) and nitric oxide in glial cultures. If naltrexone is beneficial in MS, a possible mechanism of action is through reduction in microglial nitric oxide synthase activity resulting in decreased peroxynitrites production. Peroxynitrites are thought to inhibit glutamate transporters thereby increasing the synaptic concentrations of glutamate resulting in excitatory neurotoxicity.