Drug Interaction Report

MONITOR: Beta-blockers may attenuate the response to epinephrine in the treatment of serious systemic reactions like anaphylaxis, which are possible following the administration of skin test antigens. During an anaphylactic reaction, the beneficial effects of epinephrine may be reduced due to impairment of compensatory cardiovascular responses and an increase in the release of mast cell mediators by the beta-blocker. Noncardioselective beta-blockers, in particular, can antagonize the bronchodilating effects of epinephrine by blocking beta-2 adrenergic receptors in the smooth muscles of the bronchial tree. Cardioselective beta-blockers may occasionally do the same, as beta-1 selectivity is not absolute and may be lost at higher dosages in susceptible patients. All beta-blockers can antagonize the cardiostimulatory effects of epinephrine by blocking beta-1 adrenergic receptors in the heart.

MANAGEMENT: Clinicians should be aware that patients receiving beta-blockers may be unresponsive to the usual doses of epinephrine used to treat serious allergic reactions like anaphylaxis, which could occur following the administration of skin test antigens. Some authorities suggest administration of glucagon in anaphylactic patients who are unresponsive to epinephrine. Relevant guidelines and product labeling should be consulted as indicated.