You are similarly out of luck if you need a decongestant or antihistamine. Luckily I have found one cough syrup and one antihistamine I can take. (My PD meds are Sinemet, Eldepryl, Requip, Tasmar & Nortryptiline.) The cough syrup is Naldecon Senior DX (Guaifenesin & Dextromethorphan hydrobromide) (expectorant/Cough suppressant). The antihistamine is an Eckerd's brand called Clemastine (clemastine fumarate). Good luck!