A study published in The Ocular Surface shows the off-label applicability of low-dose naltrexone (LDN) for eye pain. Because corneal neuropathic symptoms can be severe and refractory to topical anesthetics, a unique study was started to evaluate the efficacy and tolerability of LDN for the relief of corneal neuropathic pain (NCP) symptoms.
The chart review performed at Cornea Service at Tufts University Medical School in Boston represents a cohort of patients treated from July 2015 through March 2019. The 30 patients (mean age 45.60 ± 19.30) at baseline had a centralized pain component at grade 4 or higher on a scale of 0 to 10 and symptoms that persisted after administration of anesthetic drops. Participants received LDN therapy for 4 weeks or more and conducted surveys to assess eye pain before and after treatment.
LDN treatment led to meaningful results: 16 patients showed a pain reduction of 50% or more, 9 showed an improvement in symptoms of 1% to 49%, 2 showed no improvement and 3 felt unwell. The highest pain intensity reported in the last 24 hours reached a mean standard deviation (SD) of 7.00 (± 1.59) at the first visit and decreased to 4.56 (± 3.10) (P = 0.003) at the last visit highest pain level in the last 2 weeks decreased from 6.87 (± 2.07) to 2.42 (± 2.41; P = 0.008).
In addition to the pain, photoallodynia, a burning sensation and a foreign body sensation were other symptoms. Surveys confirmed that patients spent less time thinking about complaints, with a 35.56% improvement from the first appointment to the last visit (P = 0.021) and a 43.58% increase in their zest for life from the first to the last appointment (P = 0.043). .
Furthermore, the side effects were relatively minor. Of 30 in the test group, 3 had vivid dreams, 2 had a headache, 1 participant had stomach pain that subsided with a dose adjustment from 4.5 mg to 3.0 mg, and 1 in the cohort stopped therapy after reporting a headache .
Naltrexone is approved by the US Food and Drug Administration in doses of at least 50 mg for the treatment of alcohol or opioid use disorders, and off-label therapy with doses of 1.5 mg to 5 mg has already been found in the scientific literature specified in the mid-1980s.
Low dose naltrexone temporarily blocks opioid receptors and increases endogenous endorphins. It also reduces the inflammation of nerve tissue when it binds to the toll-like receptor-4 proteins on glial cells in the central and peripheral nervous systems. In previous studies, LDN outperformed placebo in reducing chronic pain in people with fibromyalgia and improving the quality of life for patients with multiple sclerosis, the researchers said.
You acknowledge that this study is retrospective and the cohort is small, but note that NCP is rare. Your analysis is the largest so far that shows the effectiveness of a possible therapy.
“Given the limited number of therapeutic options and the positive efficacy and tolerability profile of LDN, this drug could be viewed as an alternative therapy modality for the treatment of patients with refractory NCP,” the research concludes.
Disclosure: A study author stated several links to industry. For a full list of the authors’ information, see the original reference.
Dieckmann G., Ozmen MC, Cox SM, Engert RC, Hamrah P. Low-dose naltrexone is effective and well tolerated for modulating symptoms in patients with neuropathic corneal pain. Ocul Surf. Published online January 12, 2021. doi: 10.1016 / j.jtos.2020
This article originally appeared on Ophthalmology Advisor