Rosiglitazone may increase the hypoglycemic activities of Glipizide. Mechanism of Action: The mechanism of action of phenazopyridine has not been fully determined. Drugs other than those listed here may also interact with trihexyphenidyl. Thus, for many patients, treatment with EMSAM patch is significantly costly and thus may be prohibitive. Antidepressants, medicines used to treat depression (e. Based on the favorable efficacy and tolerability of LEV as an add-on therapy in refractory partial epilepsy, it is reasonable to consider it one of the first add-on therapies in these patients.