The risk or severity of adverse effects can be increased when Cetirizine is combined with Protriptyline. The risk or severity of adverse effects can be increased when Flunitrazepam is combined with Cetirizine. The therapeutic efficacy of Hyaluronidase can be decreased when used in combination with Cetirizine. The risk or severity of adverse effects can be increased when Oxprenolol is combined with Cetirizine. 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 Dyclonine 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 Perphenazine is combined with Cetirizine. 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 Pomalidomide. Cetirizine may increase the central nervous system depressant (CNS depressant) activities of Zolpidem. 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 Cetirizine is combined with Doxepin. Hydroxyzine may increase the central nervous system depressant (CNS depressant) activities of Cetirizine. The risk or severity of adverse effects can be increased when Enflurane is combined with Cetirizine. 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 Risperidone is combined with Cetirizine. Cetirizine may increase the central nervous system depressant (CNS depressant) activities of Ethanol. Dronabinol may increase the central nervous system depressant (CNS depressant) activities of Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Methocarbamol. Benzphetamine may decrease the sedative activities of 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 Molindone is combined with Cetirizine. The risk or severity of adverse effects can be increased when Piritramide is combined with Cetirizine. The risk or severity of adverse effects can be increased when Fencamfamine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Carbamazepine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Cyproheptadine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Tetrabenazine. The risk or severity of adverse effects can be increased when Bromazepam 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 Dezocine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Pethidine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Methoxyflurane is combined with Cetirizine. The risk or severity of adverse effects can be increased when Trazodone is combined with Cetirizine. The risk or severity of adverse effects can be increased when Benzyl alcohol is combined with Cetirizine. The risk or severity of adverse effects can be increased when Mesoridazine 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 Deramciclane is combined with Cetirizine. The risk or severity of adverse effects can be increased when Ecopipam is combined with 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 Cetirizine is combined with Efavirenz. The risk or severity of adverse effects can be increased when Osanetant 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 Propoxycaine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Fluspirilene is combined with Cetirizine. 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 Rufinamide is combined with Cetirizine. The risk or severity of adverse effects can be increased when Lurasidone is combined with Cetirizine. The risk or severity of adverse effects can be increased when Ethyl loflazepate is combined with Cetirizine. The risk or severity of adverse effects can be increased when Methohexital is combined with Cetirizine. The risk or severity of adverse effects can be increased when Dihydromorphine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Procaine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Citalopram. 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 7-Nitroindazole is combined with Cetirizine. The risk or severity of adverse effects can be increased when Bupivacaine 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 Halothane is combined with Cetirizine. The risk or severity of adverse effects can be increased when Ketobemidone 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 Dextromoramide is combined with 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 Cetirizine is combined with Vigabatrin. The risk or severity of adverse effects can be increased when Cetirizine is combined with Tiagabine. Cetirizine may increase the sedative activities of Pramipexole. Amphetamine may decrease the sedative activities of 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 Clorazepate is combined with Cetirizine. The risk or severity of adverse effects can be increased when Diazepam 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 Chlormezanone is combined with Cetirizine. The risk or severity of adverse effects can be increased when Dihydrocodeine 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 Indalpine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Methsuximide. Cetirizine may increase the central nervous system depressant (CNS depressant) activities of Suvorexant. The risk or severity of adverse effects can be increased when Chlorprothixene is combined with Cetirizine. The risk or severity of adverse effects can be increased when Midazolam is combined with Cetirizine. Cetirizine may increase the central nervous system depressant (CNS depressant) activities of Orphenadrine. 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 Thiamylal is combined with Cetirizine. 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 Trichloroethylene is combined with Cetirizine. Lisdexamfetamine may decrease the sedative activities of Cetirizine. Cetirizine may increase the central nervous system depressant (CNS depressant) activities of Azelastine. 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 Alfentanil is combined with Cetirizine. 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 Gepirone is combined with Cetirizine. Mephentermine may decrease the sedative activities of Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Duloxetine. The risk or severity of adverse effects can be increased when Nalbuphine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Ezogabine. The risk or severity of adverse effects can be increased when Methylecgonine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Carisoprodol. The risk or severity of adverse effects can be increased when Cetirizine is combined with Ethotoin. Chlorphentermine may decrease the sedative activities of Cetirizine. The risk or severity of adverse effects can be increased when Canertinib is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Milnacipran. The risk or severity of adverse effects can be increased when Cetirizine is combined with Difenoxin. The risk or severity of adverse effects can be increased when Cetirizine is combined with Imipramine. 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 Cetirizine is combined with Promethazine. The risk or severity of adverse effects can be increased when Chlorpromazine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Pipamperone is combined with Cetirizine. The risk or severity of adverse effects can be increased when Morphine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Carfentanil is combined with Cetirizine. The risk or severity of adverse effects can be increased when Ritanserin is combined with Cetirizine. The risk or severity of adverse effects can be increased when Halazepam 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 Methapyrilene 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 Proparacaine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Ethylmorphine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Clonidine. 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 Cetirizine is combined with Felbamate. 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 Pentobarbital is combined with Cetirizine. 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 Cetirizine is combined with Fluticasone propionate. 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 Cetirizine is combined with Chlorphenamine. 3,4-Methylenedioxyamphetamine may decrease the sedative activities of Cetirizine. 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 Amobarbital is combined with Cetirizine. The risk or severity of adverse effects can be increased when Trans-2-Phenylcyclopropylamine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Prochlorperazine is combined with Cetirizine. Diethylpropion may decrease the sedative activities of Cetirizine. The risk or severity of adverse effects can be increased when Propofol is combined with Cetirizine.