The key action in dealing with complaints is engaging with and apologising to the complainant. Making an apology does not in most cases constitute an admission of liability or guilt.
It is also important that information about how to complain is readily available. If not, people will complain directly to the GPhC, NHS England, local councils and even local newspapers.
Sometimes, all people want is an apology and someone to take personal responsibility to ensure it does not happen again. This may prevent any further action.
Unfortunately, there is a worrying trend in personal claims, reflecting an increasingly litigious society. Claims that involve solicitors can be extremely expensive. It is important that you are adequately protected and speak to your professional indemnity provider as soon as possible.