It has additive anticholinergic and sympathomimetic effects with other agents with these properties. Its use should be avoided in people receiving some types of antidepressants (tricyclic antidepressants or monoamine oxidase inhibitors) as there is the potential for serotonin syndrome or hypertensive crises to result.
Nefopam
Setiptiline
Lofexidine
Ivabradine
Fenoldopam
Verapamil
Alvimopan
Iofetamine 