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 Proparacaine is combined with Cetirizine. 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 Butabarbital 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 Cetirizine is combined with Dantrolene. The risk or severity of adverse effects can be increased when Fencamfamine is combined with Cetirizine. Doxylamine 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 Guanfacine. 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 Meprobamate is combined with Cetirizine. Cetirizine may increase the central nervous system depressant (CNS depressant) activities of Hydrocodone. The risk or severity of adverse effects can be increased when Triazolam 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 Fluphenazine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Cyclizine. The risk or severity of adverse effects can be increased when Trichloroethylene is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Ziconotide. The risk or severity of adverse effects can be increased when Valproic Acid is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Brompheniramine. 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 Fluspirilene 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 Perazine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Pethidine 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 Dimenhydrinate. 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 Cetirizine is combined with Trimipramine. The risk or severity of adverse effects can be increased when Dapiprazole is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Doxepin. Methamphetamine may decrease the sedative activities of 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 Secobarbital 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 Cetirizine is combined with Desipramine. 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 Melperone is combined with Cetirizine. Ritobegron may decrease the sedative activities of Cetirizine. Pseudoephedrine may decrease the sedative activities of Cetirizine. Tapentadol 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 Carbinoxamine. 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 Triflupromazine is combined with Cetirizine. 2,5-Dimethoxy-4-ethylamphetamine may decrease the sedative activities of Cetirizine. The risk or severity of adverse effects can be increased when Trifluoperazine is combined with 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 Etidocaine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Ondansetron is combined with Cetirizine. The risk or severity of adverse effects can be increased when Ziprasidone is combined with Cetirizine. The risk or severity of adverse effects can be increased when Lorazepam is combined with Cetirizine. The risk or severity of adverse effects can be increased when Dihydromorphine 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 Stiripentol. The risk or severity of adverse effects can be increased when Halothane is combined with Cetirizine. Dextroamphetamine may decrease the sedative activities of Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Pizotifen. The risk or severity of adverse effects can be increased when Cetirizine is combined with Levetiracetam. The risk or severity of adverse effects can be increased when Cetirizine is combined with Sertraline. Sodium oxybate may increase the central nervous system depressant (CNS depressant) activities of Cetirizine. The risk or severity of adverse effects can be increased when Ropivacaine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Primidone. Cetirizine may increase the central nervous system depressant (CNS depressant) activities of Buprenorphine. Droperidol may increase the central nervous system depressant (CNS depressant) activities of Cetirizine. The risk or severity of adverse effects can be increased when Nitrous oxide is combined with Cetirizine. The risk or severity of adverse effects can be increased when Butorphanol is combined with Cetirizine. 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 Oxymorphone is combined with Cetirizine. 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 Methaqualone 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 Dextropropoxyphene is combined with Cetirizine. 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 Desflurane is combined with Cetirizine. Diethylpropion may decrease the sedative activities of Cetirizine. The risk or severity of adverse effects can be increased when Amitriptyline is combined with Cetirizine. The risk or severity of adverse effects can be increased when Tolcapone is combined with Cetirizine. Magnesium Sulfate 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 Felbamate. 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 Nalbuphine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Tizanidine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Scopolamine. 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 Cetirizine is combined with Nefazodone. 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 Flurazepam 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 Cetirizine is combined with Brexpiprazole. The risk or severity of adverse effects can be increased when Dextromoramide is combined with Cetirizine. The risk or severity of adverse effects can be increased when Zaleplon is combined with Cetirizine. The risk or severity of adverse effects can be increased when Levobupivacaine is combined with Cetirizine. Cetirizine may increase the sedative activities of Metyrosine. 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 Lidocaine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Gabapentin is combined with Cetirizine. Brimonidine may increase the central nervous system depressant (CNS depressant) activities of Cetirizine. The risk or severity of adverse effects can be increased when Brotizolam is combined with Cetirizine. 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 Aceprometazine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Amoxapine. 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 Diphenoxylate is combined with Cetirizine. The risk or severity of adverse effects can be increased when Amisulpride is combined with Cetirizine. The risk or severity of adverse effects can be increased when Tramadol is combined with Cetirizine. The risk or severity of adverse effects can be increased when DPDPE 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 Methoxyflurane 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 Articaine 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 Pimozide 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 Thiopental 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 Prochlorperazine 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 Zopiclone 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 Mesoridazine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Bromperidol is combined with Cetirizine. The risk or severity of adverse effects can be increased when Midazolam 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 Osanetant is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cetirizine is combined with Tasimelteon. The risk or severity of adverse effects can be increased when Tiapride 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 Dyclonine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Cocaine is combined with Cetirizine. The risk or severity of adverse effects can be increased when Perospirone is combined with Cetirizine.