Hi John Meissner,
Definitely you should call your doctor. Remember, online sites are great resources for information so that you are able to ask the important questions that will help you manage your healthcare, however they can not take the place of your doctor's solid medical advice.
If you are itching it could be an allergic reaction and you don't want that to happen. If it turns out you can not take the Avodart, there are alternative medicines you can take. You can read about medicines that are prescribed for prostate issues here in the drugs database.
I hope this helps. Take care of yourself and stay in touch and let us know how you are doing.Vicki M