A dispensing error that has been spotted at the checking stage, a patient complaint regarding poor service, a dispensing error that was given to a patient or a fridge medicine left out of the fridge over the weekend. These are all incidents that could prompt an ad hoc teaching session if it was deemed to be sensible and necessary to undertake an immediate response by explaining things to staff and taking the necessary corrective actions.

It is rare to undertake any formal teaching sessions in an ad hoc manner. Therefore, the most important consideration is to decide whether to undertake the teaching there and then or to wait until a planned session can be run. If it is decided that an ad hoc session will be suitable, many of the considerations listed above for a planned session, such as the aim, objectives, content, logistics and evaluation, can all be used to help others learn from an unplanned teaching session.