rifampicin is used in tuberculosis and leprosy. Doctors had noticed PD and other neurological conditions improving while patients were taking it. Epidemiological work confirmed 3x fewer cases of PD in those patients. 16 articles turn up in pubmed on it and parkinson's. Here are three full text articles. It seems to work by upregulating a heat shock protien that prevents or reverses a-Syn misfolding. It's a lot less expensive and probably safer. This benefit was first noticed 20 years ago, but they thought it was simply increasing l-dopa.