Hi, I Was Falsely Accused Of Taking Hydrocodone In August.

Hi, I was falsely accused of taking hydrocodone in August. I told my physician I didn't take it but he believes the test not me. I didn't take it. But this is the second time I've been acussed. How can I prove I didn't. I will do anything to prove I'm innocent. I took another test but how do I trust the findings, the test has been wrong twice. I take a low grade aspirin, OxyContin, Lisinopril, vitamin D, B12'and atorvastatin all prescribe for me. I don't take anything over the counter and take my medicine as prescribed. I'm very upset what else can I do.