Cetirizine may increase the central nervous system depressant (CNS depressant) activities of Methotrimeprazine. The risk or severity of adverse effects can be increased when Chlordiazepoxide is combined with Cetirizine. The risk or severity of adverse effects can be increased when Fluphenazine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Lofentanil is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Flunarizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Meclizine. The risk or severity of adverse effects can be increased when Ethchlorvynol is combined with Cetirizine. The risk or severity of adverse effects can be increased when Amitriptyline is combined with Cetirizine. Cetirizine may increase the central nervous system depressant (CNS depressant) activities of Zolpidem. The risk or severity of adverse effects can be increased when Cetirizine is combined with Lamotrigine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Pipotiazine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Maprotiline. The risk or severity of adverse effects can be increased when Paliperidone is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Tiagabine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Alaproclate. The risk or severity of adverse effects can be increased when Cetirizine is combined with Escitalopram. The risk or severity of adverse effects can be increased when Reserpine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Flupentixol is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Olopatadine. The risk or severity of adverse effects can be increased when Loprazolam is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Efavirenz. Chlorphentermine may decrease the sedative activities of Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Desloratadine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Levocabastine. The risk or severity of adverse effects can be increased when Oxybuprocaine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Dezocine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Ecopipam is combined with Cetirizine. Cetirizine may increase the sedative activities of Pramipexole. The risk or severity of adverse effects can be increased when Quazepam is combined with Cetirizine. The risk or severity of adverse effects can be increased when Butethal is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cinchocaine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Hydromorphone is combined with Cetirizine. The risk or severity of adverse effects can be increased when Amobarbital is combined with Cetirizine. The risk or severity of adverse effects can be increased when Haloperidol is combined with Cetirizine. The risk or severity of adverse effects can be increased when Sertindole is combined with Cetirizine. The risk or severity of adverse effects can be increased when Gamma Hydroxybutyric Acid is combined with Cetirizine. The risk or severity of adverse effects can be increased when Phenobarbital is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Chlorphenamine. The risk or severity of adverse effects can be increased when Methadyl Acetate is combined with Cetirizine. The risk or severity of adverse effects can be increased when Tetrodotoxin is combined with Cetirizine. The risk or severity of adverse effects can be increased when Clemastine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Iloperidone. The risk or severity of adverse effects can be increased when Cetirizine is combined with Venlafaxine. The risk or severity of adverse effects can be increased when Secobarbital is combined with Cetirizine. The risk or severity of adverse effects can be increased when Etidocaine is combined with Cetirizine. 4-Bromo-2,5-dimethoxyamphetamine may decrease the sedative activities of Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Loratadine. The risk or severity of adverse effects can be increased when Hexobarbital is combined with Cetirizine. The risk or severity of adverse effects can be increased when Normethadone is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Cyproheptadine. Cetirizine may increase the central nervous system depressant (CNS depressant) activities of Orphenadrine. The risk or severity of adverse effects can be increased when Lidocaine is combined with Cetirizine. Hydroxyzine may increase the central nervous system depressant (CNS depressant) activities of Cetirizine. The risk or severity of adverse effects can be increased when Vortioxetine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Prazepam is combined with Cetirizine. The risk or severity of adverse effects can be increased when Phenoxyethanol is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Dimenhydrinate. Ritobegron may decrease the sedative activities of Cetirizine. The risk or severity of adverse effects can be increased when Dextropropoxyphene is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Carbinoxamine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Clonazepam. The risk or severity of adverse effects can be increased when Cetirizine is combined with Vigabatrin. The risk or severity of adverse effects can be increased when Cetirizine is combined with Ramelteon. The risk or severity of adverse effects can be increased when Fospropofol is combined with Cetirizine. The risk or severity of adverse effects can be increased when Tandospirone is combined with Cetirizine. The risk or severity of adverse effects can be increased when Ritanserin is combined with Cetirizine. Cetirizine may decrease effectiveness of Benzylpenicilloyl Polylysine as a diagnostic agent. The risk or severity of adverse effects can be increased when Cetirizine is combined with Fluoxetine. The risk or severity of adverse effects can be increased when Zopiclone is combined with Cetirizine. The risk or severity of adverse effects can be increased when Opium is combined with Cetirizine. Dextroamphetamine may decrease the sedative activities of Cetirizine. Cetirizine may increase the central nervous system depressant (CNS depressant) activities of Mirtazapine. The risk or severity of adverse effects can be increased when Benperidol is combined with Cetirizine. The risk or severity of adverse effects can be increased when Oxycodone is combined with Cetirizine. The risk or severity of adverse effects can be increased when Flunitrazepam is combined with Cetirizine. The risk or severity of adverse effects can be increased when Olanzapine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Dapoxetine. The risk or severity of adverse effects can be increased when Oxethazaine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Proparacaine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Chloroprocaine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Felbamate. The risk or severity of adverse effects can be increased when Asenapine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Tetrahydropalmatine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Fluvoxamine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Ketamine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Ethyl chloride is combined with Cetirizine. The risk or severity of adverse effects can be increased when Alfentanil is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Desipramine. The risk or severity of adverse effects can be increased when Diphenoxylate is combined with Cetirizine. Nabilone may increase the central nervous system depressant (CNS depressant) activities of Cetirizine. The risk or severity of adverse effects can be increased when Clorazepate is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Milnacipran. Cetirizine may increase the central nervous system depressant (CNS depressant) activities of Hydrocodone. The risk or severity of adverse effects can be increased when Cetirizine is combined with Nefazodone. The risk or severity of adverse effects can be increased when Heroin is combined with Cetirizine. The risk or severity of adverse effects can be increased when Adipiplon is combined with Cetirizine. The risk or severity of adverse effects can be increased when DPDPE is combined with Cetirizine. Midomafetamine may decrease the sedative activities of Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Levomilnacipran. The risk or severity of adverse effects can be increased when Cetirizine is combined with Protriptyline. Lisdexamfetamine may decrease the sedative activities of Cetirizine. The risk or severity of adverse effects can be increased when Etomidate is combined with Cetirizine. The risk or severity of adverse effects can be increased when Gabapentin is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Zonisamide. The risk or severity of adverse effects can be increased when Alprazolam is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Entacapone. The risk or severity of adverse effects can be increased when Halothane is combined with Cetirizine. The risk or severity of adverse effects can be increased when Ethyl carbamate is combined with Cetirizine. The risk or severity of adverse effects can be increased when Fludiazepam is combined with Cetirizine. The risk or severity of adverse effects can be increased when Bupivacaine is combined with Cetirizine. Cetirizine may increase the central nervous system depressant (CNS depressant) activities of Paraldehyde. The risk or severity of adverse effects can be increased when Butabarbital is combined with Cetirizine. The risk or severity of adverse effects can be increased when Clozapine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Tetracaine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Sevoflurane is combined with Cetirizine. The risk or severity of adverse effects can be increased when Perospirone is combined with Cetirizine. The risk or severity of adverse effects can be increased when Oxymorphone is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Clidinium. The risk or severity of adverse effects can be increased when Fentanyl is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Primidone. The risk or severity of adverse effects can be increased when Norflurane is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Doxepin. The risk or severity of adverse effects can be increased when Levorphanol is combined with Cetirizine. The risk or severity of adverse effects can be increased when Butalbital is combined with Cetirizine. The risk or severity of adverse effects can be increased when Melatonin is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Fluticasone propionate. Cetirizine may increase the sedative activities of Metyrosine. The risk or severity of adverse effects can be increased when Levomethadyl Acetate is combined with Cetirizine. The risk or severity of adverse effects can be increased when Butamben is combined with Cetirizine. Magnesium Sulfate may increase the central nervous system depressant (CNS depressant) activities of Cetirizine.