This is a volunteer study examining the effect of different doses of IV dexamethasone on prolongation of median nerve block in the forearm.

18 healthy volunteers aged 18-50 will be recruited (6 patients in each dosing group). Each volunteer will receive two forearm median nerve blocks separated by a two week washout period. One block will be conducted alongside an infusion of normal saline (control). The other block will be conducted alongside a randomised dose of IV dexamethasone (2, 4 or 8mg). The order of these interventions will be random. Blocks will be assessed quantitatively with cold and sharp sensation, electrical stimulation, quantitative sensory testing (thermal tolerance) and grip strength dynamometry. Measures or sensory and motor block including onset, intensity and duration will be compared between dosing groups.

Inclusion Criteria:

• ASA 1 (normal healthy) volunteers.
• 18 - 50 years of age.
• 60 - 100kg weight.
• English speaking.
• Female volunteers of childbearing potential will be required to provide a negative pregnancy test before being allowed to participate.
• Females of child bearing potential must be willing to use medically acceptable birth control methods between study interventions and for a minimum of 2 weeks following the second nerve block.

Exclusion Criteria:

• Medical disorders (including bleeding disorders).
• Use of systemic steroids within 2 weeks of the study, prescription medications, live viral vaccines or any recreational drug use.
• Hypersensitivity to bupivacaine, dexamethasone or any component of saline.
• Contraindication to regional anesthetic block.
• Inability to provide informed consent.
• Baseline abnormality of hand sensation or motor function.
• Pregnancy / breast feeding.
• Individuals with mental health disorders (for example bipolar disorder or depression).
• Individuals with cataracts or glaucoma.
• Any known contraindication to IV dexamethasone as per the product monograph - bacteremia and systemic fungal infections, hypersensitivity to any of the products components, gastric and duodenal ulcers, certain viral infections i.e. varicella herpes genitalis.