Lyrica has no effect on local anesthetics. What likely happened was that the local anesthetic wasn't delivered to the nerve the dentist was trying to block. The anatomy is different in each of us and in some people the nerve is deeper than the length of the needle the dentist is using. Also, it may be in a different location than it is in most of us. As you are probably aware, this is a blind injection so a lot of things can go wrong resulting in no anesthesia for the procedure