Capsaicin 8% patch for treprostinil subcutaneous infusion site pain in pulmonary
hypertension patients.
Author(s): Libri V(1), Gibbs JS, Pinato DJ, Iddamalgoda T, Khengar RH, Gin-Sing W, Huson L,
Anand P.
Affiliation(s): Author information:
(1)The National Institute for Health Research (NIHR) Wellcome Trust Imperial
Clinical Research Facility, Imperial Centre for Translational and Experimental
Medicine, Imperial College London, Du Cane Road, London W12 0HS, UK.
Publication date & source: 2014, Br J Anaesth. , 112(2):337-47
BACKGROUND: Treprostinil sodium improves haemodynamics and symptoms in pulmonary
arterial hypertension (PAH) patients, but its subcutaneous (s.c.) administration
can produce severe local site pain, and lead to discontinuation of vital
treatment. Treprostinil is a prostacyclin analogue which stimulates prostacyclin
receptors in skin nociceptor terminals, resulting in pain and cutaneous
hypersensitivity, for which current pain remedies have limited effect. Capsaicin
8% patch relieves neuropathic pain for 3 months after a single 60 min cutaneous
application; we investigated whether its pre-application can reduce s.c.
trepostinil-induced pain.
METHODS: A single-centre, double-blind, randomized, placebo-controlled, crossover
study was conducted to assess the safety and efficacy of a single capsaicin 8%
patch pre-application for s.c. treprostinil pain in 11 PAH patients, relative to
control patch with low-dose capsaicin 0.075% cream.
RESULTS: The primary efficacy endpoint, mean difference between the two treatment
arms in an 11-point numerical pain rating scale from baseline to 2 weeks after
patch applications, was significantly lower on the capsaicin 8% patch treatment
arm [P=0.01, mean difference=-1.47 units, 95% credible interval (CI): -2. 59 to
-0.38] in the patients who completed the study per protocol, although
intention-to-treat analysis did not show significant difference (P=0.28). Heat
pain thresholds were decreased (P=0.027, mean difference=5.43°C, 95% CI:
0.71-10.21) and laser Doppler flux increased (P=0.016, mean difference=370 units,
95% CI: 612 to 127.9) at the application site immediately after capsaicin 8%
patch, confirming activity.
CONCLUSIONS: Further investigation of the efficacy of capsaicin 8% patch in this
indication is warranted.
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