- The subject has a positive pre-study urine drug screen including alcohol at the screening visit and/or prior to receiving the first dose of study medication. Drugs that will be screened for are amphetamines, barbiturates, cocaine, opiates, cannabinoids, methadone, benzodiazepines, phencyclidine (PCP) and cotinine. If any of these tests are positive the investigator may re-test the subject and the subject may be included if the re-test is negative.