Pharmaceutical Benefits Scheme
Certain medications listed on the PBS are available only for specific therapeutic indications or to patients meeting specific criteria where the PBAC has deemed that the cost-benefit analysis is favourable only in those indications/patients. These are noted as "restricted benefits" on the Schedule. Medicare Australia places the onus of policing restricted benefits on the prescribers themselves and the pharmacists dispensing (unless the listing is also 'Authority Required'). For example, the COX-2 inhibitor celecoxib is listed on the PBS as a restricted benefit for the symptomatic treatment of osteoarthritis and rheumatoid arthritis. Prescribers using celecoxib for other indications are expected to indicate "non-PBS" on the prescription, and/or the pharmacist dispensing the celecoxib should charge the patient the full cost.
Pharmacology of bicalutamide
All of the approved for the treatment of prostate cancer have been found to possess an off-target action of acting as weak non-competitive inhibitors of human GABA receptor currents "in vitro" to varying extents. The values are 44 μM for flutamide (as hydroxyflutamide), 21 μM for nilutamide, 5.2 μM for bicalutamide, and 3.6 μM for enzalutamide. In addition, flutamide, nilutamide, and enzalutamide have been found to cause convulsions and/or death in mice at sufficiently high doses. Bicalutamide was notably not found to do this, but this was likely simply due to the limited central nervous system penetration of bicalutamide in this species. In any case, enzalutamide is the only approved that has been found to be associated with a significantly increased incidence of seizures and other associated side effects clinically, so the relevance of the aforementioned findings with regard to bicalutamide and the other is unclear.