The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Rizatriptan. The metabolism of Dextromethorphan can be decreased when combined with Quinine. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Pimozide. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Droperidol. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Quetiapine. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Melperone. The serum concentration of the active metabolites of Dabigatran etexilate can be increased when Dabigatran etexilate is used in combination with Dextromethorphan. The metabolism of Dextromethorphan can be decreased when combined with Artemether. Zimelidine may increase the serotonergic activities of Dextromethorphan. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Sumatriptan. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Olanzapine. The metabolism of Dextromethorphan can be decreased when combined with Zucapsaicin. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Ritanserin. Selegiline may increase the serotonergic activities of Dextromethorphan. The metabolism of Dextromethorphan can be decreased when combined with Telaprevir. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Lurasidone. The metabolism of Dextromethorphan can be decreased when combined with Verapamil. Desvenlafaxine may increase the serotonergic activities of Dextromethorphan. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Clomipramine. The metabolism of Dextromethorphan can be decreased when combined with Dronedarone. The serum concentration of Naloxegol can be increased when it is combined with Dextromethorphan. The metabolism of Dextromethorphan can be decreased when combined with Darifenacin. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Osanetant. Palonosetron may increase the serotonergic activities of Dextromethorphan. The metabolism of Dextromethorphan can be decreased when combined with Cocaine. The serum concentration of Ledipasvir can be increased when it is combined with Dextromethorphan. The metabolism of Dextromethorphan can be decreased when combined with Cyclosporine. The risk or severity of adverse effects can be increased when Tramadol is combined with Dextromethorphan. The metabolism of Dextromethorphan can be increased when combined with Carbamazepine. The metabolism of Dextromethorphan can be decreased when combined with Lopinavir. The metabolism of Dextromethorphan can be decreased when combined with Voriconazole. The metabolism of Dextromethorphan can be decreased when combined with Diphenhydramine. Granisetron may increase the serotonergic activities of Dextromethorphan. The metabolism of Dextromethorphan can be decreased when combined with Nicardipine. Nialamide may increase the serotonergic activities of Dextromethorphan. The metabolism of Dextromethorphan can be decreased when combined with Etravirine. The serum concentration of Rifaximin can be increased when it is combined with Dextromethorphan. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Maprotiline. The metabolism of Dextromethorphan can be decreased when combined with Gemfibrozil. The metabolism of Dextromethorphan can be decreased when combined with Pantoprazole. The serum concentration of Dextromethorphan can be decreased when it is combined with Deferasirox. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Amoxapine. The metabolism of Dextromethorphan can be decreased when combined with Fluvastatin. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Fluspirilene. The metabolism of Dextromethorphan can be decreased when combined with Clotrimazole. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Sertindole. The metabolism of Dextromethorphan can be decreased when combined with Lobeglitazone. The serum concentration of Vincristine can be increased when it is combined with Dextromethorphan. The serum concentration of Colchicine can be increased when it is combined with Dextromethorphan. The metabolism of Dextromethorphan can be decreased when combined with Fluorouracil. The metabolism of Dextromethorphan can be decreased when combined with Olaparib. The serum concentration of Dextromethorphan can be increased when it is combined with Palbociclib. Iproniazid may increase the serotonergic activities of Dextromethorphan. The metabolism of Dextromethorphan can be decreased when combined with Bortezomib. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Acetophenazine. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Tapentadol. The metabolism of Dextromethorphan can be decreased when combined with Mirabegron. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Remoxipride. The metabolism of Dextromethorphan can be increased when combined with Phenytoin. The risk or severity of adverse effects can be increased when Buspirone is combined with Dextromethorphan. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Loxapine. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Linezolid. The serum concentration of the active metabolites of Fesoterodine can be increased when Fesoterodine is used in combination with Dextromethorphan. The serum concentration of Dextromethorphan can be increased when it is combined with Fosaprepitant. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Nortriptyline. The serum concentration of Conivaptan can be increased when it is combined with Dextromethorphan. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Raclopride. Octamoxin may increase the serotonergic activities of Dextromethorphan. The risk or severity of adverse effects can be increased when Vortioxetine is combined with Dextromethorphan. Dolasetron may increase the serotonergic activities of Dextromethorphan. The metabolism of Dextromethorphan can be decreased when combined with Pioglitazone. The risk or severity of adverse effects can be increased when Amitriptyline is combined with Dextromethorphan. Etoperidone may increase the serotonergic activities of Dextromethorphan. The metabolism of Dextromethorphan can be decreased when combined with Crizotinib. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Brexpiprazole. The serum concentration of Dextromethorphan can be increased when it is combined with Simeprevir. The metabolism of Dextromethorphan can be decreased when combined with Erythromycin. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Pipotiazine. The metabolism of Dextromethorphan can be decreased when combined with Amiodarone. The metabolism of Dextromethorphan can be decreased when combined with Thiotepa. Moclobemide may increase the serotonergic activities of Dextromethorphan. The serum concentration of Dextromethorphan can be increased when it is combined with Luliconazole. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Dapiprazole. The metabolism of Dextromethorphan can be decreased when combined with Esomeprazole. Pirlindole may increase the serotonergic activities of Dextromethorphan. The metabolism of Dextromethorphan can be decreased when combined with Leflunomide. Phenoxypropazine may increase the serotonergic activities of Dextromethorphan. Iproclozide may increase the serotonergic activities of Dextromethorphan. The metabolism of Dextromethorphan can be decreased when combined with Chloramphenicol. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Aceprometazine. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Trifluoperazine. The metabolism of Dextromethorphan can be decreased when combined with Rosiglitazone. The serum concentration of Dextromethorphan can be increased when it is combined with Vemurafenib. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Thioproperazine. The serum concentration of Edoxaban can be increased when it is combined with Dextromethorphan. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Tetrahydropalmatine. The risk or severity of adverse effects can be increased when Pethidine is combined with Dextromethorphan. The metabolism of Dextromethorphan can be decreased when combined with Topiroxostat. The metabolism of Dextromethorphan can be decreased when combined with Capecitabine. The metabolism of Dextromethorphan can be decreased when combined with Rolapitant. The metabolism of Dextromethorphan can be decreased when combined with Idelalisib. Harmaline may increase the serotonergic activities of Dextromethorphan. The serum concentration of Dextromethorphan can be increased when it is combined with Ceritinib. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Bromperidol. The serum concentration of Dextromethorphan can be increased when it is combined with Mifepristone. The metabolism of Dextromethorphan can be increased when combined with Phenobarbital. Toloxatone may increase the serotonergic activities of Dextromethorphan. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Aripiprazole. The serum concentration of Dextromethorphan can be increased when it is combined with Netupitant. The serum concentration of Dextromethorphan can be decreased when it is combined with Dabrafenib. The metabolism of Dextromethorphan can be decreased when combined with Clobazam. Venlafaxine may increase the serotonergic activities of Dextromethorphan. The serum concentration of Dextromethorphan can be increased when it is combined with Quinidine. The metabolism of Dextromethorphan can be decreased when combined with Armodafinil. Nefazodone may increase the serotonergic activities of Dextromethorphan. The metabolism of Dextromethorphan can be decreased when combined with Irbesartan. The metabolism of Dextromethorphan can be increased when combined with Rifabutin. Safrazine may increase the serotonergic activities of Dextromethorphan. The metabolism of Dextromethorphan can be decreased when combined with Zafirlukast. The metabolism of Dextromethorphan can be decreased when combined with Fosamprenavir. The risk or severity of adverse effects can be increased when Imipramine is combined with Dextromethorphan. The metabolism of Dextromethorphan can be increased when combined with Nevirapine. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Promethazine. The risk or severity of adverse effects can be increased when Dihydroergotamine is combined with Dextromethorphan. The metabolism of Dextromethorphan can be decreased when combined with Lapatinib. The risk or severity of adverse effects can be increased when Dextromethorphan is combined with Doxepin. The metabolism of Dextromethorphan can be decreased when combined with Methotrimeprazine. The metabolism of Dextromethorphan can be decreased when combined with Fluconazole. The metabolism of Dextromethorphan can be decreased when combined with Teriflunomide. The serum concentration of Silodosin can be increased when it is combined with Dextromethorphan.