Low-dose naltrexone can be used  to treat neuropathic corneal pain as it has good tolerability and efficacy.

A retrospective trial was carried to investigate the tolerability and efficacy of oral low-dose naltrexone in individuals suffering from refractory neuropathic corneal pain.

In total, 59 neuropathic corneal pain subjects having a centralized component treated with low-dose (4.5 mg) naltrexone at bedtime for at least 4 weeks were recognized. Notably, 30/59 participants who had a baseline pain score ≥4 on the visual analogue scale had completed the ocular pain assessment survey and witnessed constant pain, despite topical anesthetic drops instillation. Alteration in pain scores, comorbidities, adverse effects, among others, were assessed. Alteration in the quality of life scores (scale 0-100%) and the ocular pain scores (scale 0-10) were the primary outcomes.

The duration of neuropathic corneal pain prior to therapy was 17.53 ± 17.29 months and the duration of low-dose naltrexone usage was 14.87 ± 11.25 months. In total, eight participants utilized low-dose naltrexone as a monotherapy, and the remaining participants utilized it as an adjunct treatment.

Low-dose naltrexone led to a 49.22% decline in the mean pain score from 6.13 ± 1.93 to 3.23 ± 2.60. The mean quality of life scores by the ocular pain evaluation survey was 5.84 ± 2.57 at the initial visit and improved to 3.77 ± 2.91 at the last visit. Headaches, vivid dreams, and stomachaches were the common adverse effects. 

Low-dose naltrexone has good tolerability and is effective to modulate symptoms in individuals having neuropathic corneal pain.