11. Positive drug tests at Screening (V1) or Randomization (V2) visits for any of the following substances or classes of compounds: amphetamines, barbiturates, opiates, benzodiazepines, sedatives and hypnotics, cocaine, phencyclidine (PCP), cannabinoids, or other illegal or illicit drugs. An exception to the exclusion for a positive benzodiazepine, opiate, or sedative and hypnotic drug test at the Screening (V1) visit may be granted by the Pfizer medical monitor if written evidence of a valid, current prescription is presented.