- Medications a) Use of centrally active beta-blockers, narcotics, methyldopa and clonidine within 4 weeks prior to screening. b) Use of anti-Parkinsonian medications (e.g. Sinemet, amantadine, bromocriptine, pergolide and selegiline) within 2 months prior to screening. c) Use of neuroleptics or narcotic analgesics within 4 weeks prior to screening. d) Use of long-acting benzodiazepines or barbituates within 4 weeks prior to screening. e) Use of short-acting anxiolytics or sedative hypnotics more frequently than 2 times per week within 4 weeks prior to screening (note: sedative agents should not be used within 72 hours of screening).