Dentists Warned Against Signing Cannabis Prescriptions Before Seeing Patients Thai authorities have warned dentists not to pre-sign cannabis prescription documents before examining or diagnosing individual patients. The Por.Tor.33 forms are intended for legitimate medical prescriptions, and signing them in advance could allow cannabis to be distributed without a proper diagnosis or treatment plan. Officials say the practice violates professional dental ethics while potentially breaching four separate pieces of Thai legislation. Those include laws governing controlled herbs, narcotics, the dental profession and healthcare facilities. No individual dentist or clinic was named in the warning, which comes as Thailand continues tightening cannabis regulations and restricting legal use primarily to medical purposes.