Capsaicin 8% patch for treprostinil subcutaneous infusion site pain in pulmonary hypertension patients.
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.
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.
V
V
Libri
J S R
JS
Gibbs
D J
DJ
Pinato
T
T
Iddamalgoda
R H
RH
Khengar
W
W
Gin-Sing
L
L
Huson
P
P
Anand
D000328:Adult; D000368:Aged; D000959:Antihypertensive Agents / Q000009:adverse effects* / Q000627:therapeutic use; D002211:Capsaicin / Q000008:administration & dosage / Q000627:therapeutic use*; D004311:Double-Blind Method; D011464:Epoprostenol / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000188:drug therapy*; D055104:Infusions, Subcutaneous; D008131:London; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000139:chemically induced / Q000188:drug therapy*; D018689:Sensory System Agents / Q000008:administration & dosage / Q000627:therapeutic use; D057968:Transdermal Patch; D016896:Treatment Outcome
D000959:Antihypertensive Agents; D018689:Sensory System Agents; D011464:Epoprostenol; C427248:treprostinil; D002211:Capsaicin
capsaicin 8%; clinical trial; pain; pulmonary arterial hypertension; treprostinil