Drug Interactions between gadobenate dimeglumine and timolol ophthalmic

MONITOR: Limited data suggest that patients receiving beta-blockers may have an increased risk of severe hypotensive and/or hypersensitivity reactions to parenteral contrast media. In addition, allergic/anaphylactoid reactions in these patients may be more difficult to treat. The mechanism is unknown. Theoretically, beta-blocker ophthalmic solutions may also interact, as they are systemically absorbed and can produce clinically significant systemic effects even at low or undetectable plasma levels.

MANAGEMENT: Patients who have received beta-blockers should be closely monitored for adverse reactions to contrast media. If anaphylaxis occurs, clinicians should be aware that beta-blockers may attenuate the response to epinephrine. Thus, larger doses of epinephrine may be necessary to overcome the bronchospasm, although such large doses can also cause excessive alpha-adrenergic stimulation resulting in hypertension, reflex bradycardia, heart block, and possible potentiation of bronchospasm. Alternative treatments recommended include vigorous supportive care (e.g., fluids) and the use of parenteral beta-agonists for bronchospasm and norepinephrine for hypotension.