* Atrioventricular (AV) block, complete, without implanted pacemaker or at high risk of complete AV block * Concomitant use with drugs containing<unk> , quinine, or mefloquine * Concomitant use with drugs that both prolong the QT interval and are metabolized by CYP2D6 (e.g., thioridazine, pimozide); effects on QT interval may be increased * Concomitant use with MAOIs or use of MAOIs within 14 days; risk of serious, potentially fatal, drug interactions including serotonin syndrome * Heart failure * Hypersensitivity to<unk>  * Hypersensitivity to quinine, mefloquine,<unk> , or<unk>  with a history of thrombocytopenia, hepatitis, bone marrow depression or lupus-like syndrome induced by these drugs * QT interval, prolonged or congenital long QT syndrome or a history suggesting torsades de pointes
Dextromethorphan/quinidine
Fentanyl/fluanisone
Bupivacaine/meloxicam
Oxycodone/naloxone
Desloratadine/pseudoephedrine
Pseudoephedrine/loratadine
Phenylephrine/ketorolac
Buprenorphine/naloxone