For PD patients taking monoamine oxidase B inhibitors (MAOI) like rasagiline, safinamide and selegiline, more serious drug-drug interactions can occur if taken together with cough syrups containing dextromethorphan or nasal decongestants containing pseudoephedrine, phenylephrine or phenylpropanolamine [11]. This evidence concerns the gene MAOB and Parkinson disease.