To Study the Peripheral Effect of Botulinum Toxin-A (Botox-A) on Experimentally Induced Cutaneous Pain in Healthy Subjects
Status:
Completed
Trial end date:
2008-01-01
Target enrollment:
Participant gender:
Summary
This is a human trial to study the peripheral effect of therapeutic botulinum toxin
(botox-A). The trial is performed on healthy normal males. The study comprises of two
parallel placebo-controlled, double blinded studies.
In experiment 1 intramuscular Botox will be given in corrugator (one site) and frontalis (two
sites) muscles on one side and placebo to the other side. Intradermal (i.d.) capsaicin
injection will be given to both sides (between the two sites of frontalis injection
horizontally). Capsaicin-induced pain intensity and flare together with the area of
hypersensitivity to different stimulus modalities will be measured and mapped at specific
time points using different cutaneous stimuli (thermal, electrical, tactile, pressure). This
will characterize which fibres and receptors are affected by Botox and will show if Botox
have a unilateral effect (peripheral) or if it also affects the contralateral side (central
effect).
In experiment 2 intradermal Botox will be given in corrugator (one site) and frontalis (two
sites) muscles on one side and placebo to the other side. I.d. capsaicin injection will be
given to both sides (between the two sites of frontalis injection horizontally).
Capsaicin-induced pain intensity and flare together with the area of hypersensitivity to
different stimulus modalities will be measured and mapped at specific time points using
different cutaneous stimuli (thermal, electrical, tactile, pressure). This will characterize
which fibres and receptors are affected by Botox. The effect of intradermal Botox will be
compared to the results of experiment 1.
The two experiments will show if the intramuscular Botox exerts its action via a leak of
Botox from the muscle to the overlying skin.
Antipruritic effects of Botox on histamine prick test and itch will also be assessed in
parallel with the experiment 2. In this sub-experiment, 5 Units of Botox will be injected
intradermally in the middle of volar forearm. The same volume of placebo will be injected
into the other side. Histamine prick test will induce itch and the effect of intradermal
Botox will be assessed compared to the baseline. Flare area and visual analogue scale (VAS)
ratings will be measured.
Phase:
N/A
Details
Lead Sponsor:
Aalborg University
Collaborators:
Aalborg Universitetshospital Aalborg University Hospital