If a person is charged with a felony drug charge and the informant is represented by the same lawyer does this cause a conflict of interest?

Yes, it would be a conflict of interest for a lawyer to represent both you as the defendant and the informant who set you up and may be a witness against you. The Sixth Amendment to the U.S. Constitution guarantees you the right to effective assistance of counsel, and that means counsel free of any conflicts of interest. Having represented the informant, the lawyer would be unable to use the information he or she learned during the course of that representation to assist you, particularly during cross-examination. It would be privileged. As a client, you are entitled to know that your lawyer's loyalties lie only with you. When he or she also represents your accuser, dual loyalties exist and you cannot be sure that your lawyer will be looking out for your best interest. You should raise the issue with your lawyer. I would be surprised if he or she did not agree and suggest withdrawing from your case. If that doesn't happen, you should ask him or her to file a motion with the Court which lays out the facts of his representation of both of you so the court can decide. In the meantime, you may want to consult another experienced defense attorney in your area, disclose all the facts about the dual representation of which you are aware, so that he or she can provide you with more detailed and specific advice on how to best resolve the conflict.