A Good Probiotic for my Beardie?

Hello all, I am writing trying to figure out if someone may be able to help me... I recently gave my dragon antibiotics due to a respiratory infection and I have been doing a little research at the same time. I have read that you need to follow up with a probiotic cycle after administering the full antibiotic cycle which makes sense because antibiotics destroy both good and bad living organisms internally. Does anyone have any knowledge of a good over-the-counter probiotic or am I better off just taking him down to the vet and seeing about a prescription? Any help is greatly appreciated. Thanks!!