Nortriptyline is Effective in Ameliorating Symptoms of Neuropathic Corneal Pain

Abstract

Purpose : Neuropathic corneal pain (NCP) is characterized by chronic pain of the cornea, and is associated with symptoms of allodynia and hyperalgesia, and can lead to central sensitization. The aim of this study is to assess the efficacy and tolerability of the tricyclic antidepressant, nortriptyline hydrochloride, among NCP patients with centralized component of pain.

Methods : A retrospective chart review of patients with clinically diagnosed NCP, treated with oral nortriptyline (starting dose of 10 to 25mg, increasing every 3 days up to 100mg as tolerated), between July 2015 and January 2018 was performed. Patients with pain, with centralized component and presence of microneuromas on in vivo confocal microscopy images, who had refractory symptoms despite topical and/or oral therapies were included. Age, gender, systemic diseases, ocular pain scores (visual analogue scale- VAS, at the visit when nortriptyline was prescribed, and the last visit nortriptyline was used), duration of nortriptyline use, side effects, reason for discontinuation, and concurrent therapies (Table 1), were recorded. Patients who used the drug less than 4 weeks were excluded.

Results : Twenty-five patients with a mean age of 54.92±17.61 were included. Male to female ratio was 7/18. VAS pain score improved in 21 (84%) patients by 40.3% (from 6.36±2.18 to 3.8±2.39, p<0.0001). Mean duration of nortriptyline use 9.64±8.87 was months. Seven patients (28%) had more than 50% improvement, 10 patients (40%) had 25-50% improvement, and 8 patients (32%) had less than 25% improvement. Mixed model analyses yielded that nortriptyline had a significant effect on VAS (p<0.0001), whereas age, gender, and use of concurrent therapies (anti-inflammatory therapy, neuro-regenerative treatment, systemic pharmacotherapy, and adjunctive treatment) had no statistically significant effect (p>0.05). Eight patients (32.0%) had to discontinue after 7.63±5.71 months due to persistent mild side effects, despite improvement by 22.4%. These side effects resolved after cessation of use.

Conclusions : Nortriptyline is relatively safe and effective as an adjunct treatment for pain symptoms in NCP, particularly for patients with centralized component, refractory to other topical and systemic therapies.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.

 

Frequencies of treatment strategies (n=25). NSAID: nonsteroidal anti-inflammatory drugs, SNRI: serotonin and norepinephrine reuptake inhibitors, IVIG: intravenous immunoglobulin.