To Study the Peripheral Effect of Botulinum Toxin-A (Botox-A) on Experimentally Induced Cutaneous Pain in Healthy Subjects

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.

Conditions

• Healthy

Interventions

DRUG

Botox (Allergan Inc., US)

Sponsors & Collaborators

• Aalborg University Hospital

  collaborator OTHER

• Aalborg University

  lead OTHER

Principal Investigators

• Lars - Arendt-Nielsen, Prof., Dr.Med.Sci., Ph.D. · Aalborg University, Center for Sensory-Motor Interaction (SMI)

• Asbjoern Mohr Drewes, MD, PhD, DMSc, Prof. · Aalborg University Hospital

Study Design

Allocation

RANDOMIZED

Purpose

HEALTH_SERVICES_RESEARCH

Masking

DOUBLE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

40 Years

Sex

MALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2007-03-31

Primary Completion

2008-01-31

Completion

2008-01-31

Countries

• Denmark

Study Locations