For aikido seminars, public demonstrations, and dan examinations, the WADA rules on TUE (Therapeutic Use Exemption) may apply. Please consult the national anti-doping organization of the event in question, for specifics about these rules.
For IAF events, if the national anti-doping organization doesn't clarify your situation, please contact the IAF.
Future IAF events where TUE applies:
2012: IAF International Seminar and Aikido Demonstrations, Tokyo, September
2013: Combat Games, S:t Petersburg, October
Other events may be added to the list.