Disclosed are methods of treating Parkinson's disease by (i) providing a pharmaceutical composition in unit dosage form that is a film having a first portion including apomorphine particles containing an acid addition salt of apomorphine and a second portion containing a pH neutralizing agent, where the film contains the acid addition salt of apomorphine in an amount effective to treat Parkinson's disease, and (ii) administering the film by placing the film sublingually in the mouth of the subject and contacting sublingual mucosal tissue with the film.