New research on low dose naltrexone for treating a variety of chronic conditions is being published on a monthly basis. Recent research has been done that used low dose naltrexone on patients with fibromyalgia, corneal neuropathic pain, cancer, immunothrombosis in COVID-19, epilepsy, and more. A biopharmaceutical company has released data from their Phase 1 clinical trial utilizing low dose naltrexone to treat patients with fibromyalgia. They are calling their product SP-104, which is a 4.5mg delayed-burst release low dose naltrexone product.
Current Fibromyalgia Treatments
Fibromyalgia is a difficult condition for many patients to manage. Many patients express dissatisfaction with current treatments that are available. The pain of fibromyalgia can occur throughout the body and includes aches and stiffness accompanied by fatigue. In general it is thought that fibromyalgia is associated with abnormal nerve responses. The pain of this condition occurs without any visible cause of the pain.
Current treatments for fibromyalgia include the FDA approved drugs pregabalin (Lyrica), duloxetine (Cymbalta), and milnacipran (Savella). First-line treatments are indicated for treating other conditions like depression and nerve pain include amitriptyline (Elavil), cyclobenzaprine (Flexeril), or gabapentin (Neurontin). Rheumatologists are frequently the specialists who treat fibromyalgia however general practitioners and other doctors may prescribe these medications as well.
Low Dose Naltrexone for Fibromyalgia
Low dose naltrexone is already used to treat fibromyalgia pain for some patients who have the drug made by a compounding pharmacy. Dosages of 1.5mg to 4.5mg are typically compounded in capsules. The only commercially available form of naltrexone right now is in 50mg tablets, which is too high of a dose to obtain the desired effects. At the lower doses, naltrexone exhibits different effects that make it a promising treatment for chronic pain conditions.
Currently compounding pharmacies make all dosages that are under 5mg, which are the dosages typically referred to as “LDN” and used to treat chronic conditions. A compounding pharmacy makes naltrexone either from the 50mg tablets or using a bulk powder to get the exact dosage. No matter how LDN is obtained, it is available by prescription only.
Phase 1 Clinical Trial of LDN for Fibromyalgia
Scilex Holding Company (“Scilex”) and a biopharmaceutical company are looking to commercialize low dose naltrexone with an indication for fibromyalgia pain. The phase 1 studies are intended to establish the pharmacokinetic profile and safety of the low lode naltrexone 4.5mg product.
The delayed burst technology of SP-104 is intended to bypass the stomach and release the naltrexone in the upper intestine. The drug is administered before bed to maximize efficacy and reduce perception of side effects. In the phase 1 trial, patients who were given the delayed burst product has less side effects than those given the immediate release form.
Previous Research on LDN and Fibromyalgia
Many case studies and clinical trials have been conducted that study the effects of low dose naltrexone in patients with fibromyalgia and other chronic pain conditions. In a small clinical trial of 10 patients conducted at Stanford University, LDN reduced symptoms by 30% compared to placebo. While this is a small trial, it showed that LDN is worth pursuing as a potential treatment.
If LDN is effective for treating fibromyalgia it may also be useful for reducing the use of opioids to treat chronic pain. As opioids have potentially severe adverse effects as well as addiction potential many doctors are looking for alternatives for pain treatment. LDN has few side effects and no addiction potential – meaning that if the same pain reduction (or better) can be achieved as with an opioid it could be a great benefit for patients.
Many interesting case studies have also been conducted that utilize LDN for fibromyalgia patients. One case study involved a 60 year old man with chronic pain and depression. Fibromyalgia and depression are considered comorbid conditions. The patient in this case study had tried numerous medications including opioids but had discontinued their use at the time of the study. Small studies had already confirmed that LDN may be effective for both depression and fibromyalgia. This patient in particular had a remission in both fibromyalgia and depression when their treatment was combined with psychotherapy. He was also able to eliminate his use of benzodiazepines.
Next Steps for SP-104
The Phase 2 study for SP-104 is planned for the second half of 2022. Future trials will compare naltrexone 4.5mg to placebo in its effectiveness in treating fibromyalgia. Should future clinical trials show that LDN is more effective than a placebo, it may well be on its way to being approved by the FDA. This would increase the availability of LDN for many patients and increase its acceptability as a treatment for chronic conditions.
Articles
Fibromyalgia Symptoms Are Reduced by Low-Dose Naltrexone: A Pilot Study – Pain Med
Depression in Fibromyalgia Patients May Require Low-Dose Naltrexone to Respond: A Case Report – Cureus