scholarly journals The effect of a topical combination of clonidine and pentoxifylline on post-traumatic neuropathic pain patients: study protocol for a randomized, double-blind placebo-controlled trial

Trials ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Oli Abate Fulas ◽  
André Laferrière ◽  
D. Mark A. Ware ◽  
Yoram Shir ◽  
Terence J. Coderre

Abstract Background First-line pharmacotherapy for neuropathic pain entails the use of systemic antidepressants and anticonvulsants. These drugs are not optimally effective and poorly tolerated, especially for older patients with comorbid conditions. Given the high number of such patients, there is a need for a greater repertoire of safer and more effective analgesics. Clonidine and pentoxifylline are vasodilator agents that work synergistically to enhance tissue perfusion and oxygenation. The topical administration of these drugs, individually and in combination, has shown anti-nociceptive properties in rodent models of neuropathic pain. A topically-administered combination of clonidine and pentoxifylline also effectively reduced the intensity of both spontaneous and evoked pain in healthy volunteers with experimentally-induced neuropathic pain. The next step in advancing this formulation to clinical use is the undertaking of a phase II clinical study to assess its efficacy and safety in neuropathic pain patients. Methods/design This is a study protocol for a randomized, double-blind, placebo-controlled, phase II clinical trial with a cross-over design. It is a single-centered, 5-week study that will enroll a total of 32 patients with post-traumatic peripheral neuropathic pain. Patients will be treated topically with either a combination of clonidine and pentoxifylline or placebo for a period of 2 weeks each, in randomly assigned order across patients, with an intervening washout period of 1 week. The primary outcome measures of the study are the intensity of spontaneous pain recorded daily in a pain diary with a visual analog scale, and the degree of mechanical allodynia evoked by a brush stimulus. The secondary outcome measures of the study include scores of pain relief and change in the area of punctate hyperalgesia. This trial has been prospectively registered with ClinicalTrials.gov on November 1, 2017. ClinicalTrials.gov Identifier: NCT03342950. Discussion The analgesic use of topical treatment with clonidine and pentoxifylline in combination has not been investigated in post-traumatic neuropathic pain. This study could generate the first evidence for the efficacy and safety of the formulation in alleviating pain in patients with neuropathic pain. Furthermore, this trial will provide objective grounds for the investigation of other agents that enhance tissue oxygenation in the topical treatment of peripheral neuropathic pain. Trial registration This trial has been registered with ClinicalTrials.gov owned by NIH’s US National Library of Medicine. ClinicalTrials.gov NCT03342950. Registered on November 1, 2017 (trial was prospectively registered). Protocol version and identifiers This is protocol version 5, dated June 2018. McGill University Health Center (MUHC) Reaseach Ethics Board (REB) identification number: TTNP 2018-3906.

2018 ◽  
Vol 265 (12) ◽  
pp. 2815-2824 ◽  
Author(s):  
John Markman ◽  
Malca Resnick ◽  
Scott Greenberg ◽  
Nathaniel Katz ◽  
Ruoyong Yang ◽  
...  

Pain ◽  
2009 ◽  
Vol 146 (3) ◽  
pp. 245-252 ◽  
Author(s):  
Michael C. Rowbotham ◽  
Rachel W. Duan ◽  
James Thomas ◽  
Wolfram Nothaft ◽  
Misha-Miroslav Backonja

2017 ◽  
Vol 2 (20;2) ◽  
pp. 27-35
Author(s):  
PyungBok Lee

Background: Topical capsaicin therapy may be of benefit in providing pain relief in patients with peripheral neuropathy. Objectives: To investigate the efficacy and safety of 0.625% (50 µg/cm2 ) and 1.25% (100 µg/cm2 ) capsaicin patches (CPs) compared to conventional 0.075% capsaicin cream or placebo patches in patients suffering from peripheral neuropathy. Study Design: Early Phase II, multi-center, randomized, semi-double-blind, and placebocontrolled clinical trial. Setting: Two medical college teaching hospitals. Methods: Sixty patients were randomized to the 0.625% CP, 1.25% CP, placebo-controlled patch, or 0.075% capsaicin cream. The primary efficacy endpoint was the mean difference in the change of daily numerical rating scale (NRS) pain score. Secondary endpoints included values for the Daily Sleep Interference Scale, the percentage of patients achieving a ≥ 30% or ≥ 50% reduction in pain, and data for Global Impression Change (GIC) and EQ-5D. Results: Patients treated with the 0.625% CP and 0.075% capsaicin cream showed statistically significant improvements in pain after 6-weeks of test drug application. Daily sleep disorder scores were improved only for those patients applying the 0.075% capsaicin cream. For patient-derived GIC scores, the majority (11 of 12) of patients in the 0.625% CP group reported that their pain was improved. For the safety evaluation, 2 severe adverse events were reported for the 0.075% capsaicin cream group only. Repetitive patch application was related to minor skin problems such as a burning sensation, erythema, pruritus, and vesicles in 28 patients (46.67%). Limitations: The small sample size and relatively high dropout rates. Conclusion: Our data indicate that the 0.625% CP may prove to be an effective and safe alternative with which to treat patients with peripheral neuropathy and could replace the high concentration (8%) CP. Further studies are now needed to definitively establish efficacy. Key words: Capsaicin, patch, CP, topical capsaicin, neuropathic pain, peripheral neuropathic pain, PNP, high concentration CP


2019 ◽  
Vol 18 (2) ◽  
pp. 583-583
Author(s):  
Khojasteh Joharchi ◽  
Moosareza Memari ◽  
Eznollah Azargashb ◽  
Navid Saadat

The article Efficacy and safety of duloxetine and Pregabalin in Iranian patients with diabetic peripheral neuropathic pain: a double-blind, randomized clinical trial, written by Khojasteh Joharchi, Moosareza Memari, Eznollah Azargashb, and Navid Saadat, was originally published.


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