The Effects of Topical Treatment With Clonidine + Pentoxifylline in Patients With Neuropathic Pain
Status:
Terminated
Trial end date:
2021-10-12
Target enrollment:
Participant gender:
Summary
Microvascular dysfunction underlies pain in different animal models of neuropathic pain.
Pentoxifylline is a phosphodiesterase inhibitor that reduces cyclic adenosine monophosphate
(cAMP) hydrolysis, enhances blood flow and reduces platelet aggregation, decreases blood
viscosity, and increases the flexibility of red blood cells, all of which relieve
microvascular dysfunction. Clonidine is an α2-adrenergic receptor agonist that decreases
sympathetic outflow from the brainstem, vascular reactivity and has direct peripheral
vasodilatory action. Topical combination of pentoxifylline and clonidine produced significant
antiallodynic effects in rat models of neuropathic pain with sciatic nerve injury, painful
diabetic neuropathy, and chemotherapy-induced painful neuropathy. In healthy volunteers with
an experimentally-induced surrogate for neuropathic pain: post-capsaicin tourniquet exposure,
the topical combination reduced areas of dynamic allodynia and mechanical hyperalgesia, in
addition to reducing post-capsaicin ischemic pain.
This study will investigate if the same topical combination of clonidine + pentoxifylline
will relieve pain in patients with neuropathic pain following traumatic injuries of
peripheral nerves.