Therapeutic synergism.
D001249:Asthma / Q000188:drug therapy*; D004357:Drug Synergism; D004809:Ephedrine / Q000627:therapeutic use; D006801:Humans; D006919:Hydroxyzine / Q000627:therapeutic use; D009921:Metaproterenol / Q000627:therapeutic use; D009626:Terminology as Topic; D013806:Theophylline / Q000627:therapeutic use*
D006919:Hydroxyzine; D009921:Metaproterenol; D013806:Theophylline; D004809:Ephedrine