Drug General Information (ID: DDI3L8Y549)
Drug Name			Timolol (ophthalmic)		Drug Info		Epinephrine		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antiarrhythmic Agents				Vasoconstrictor Agents
Structure

Mechanism of Timolol (ophthalmic)-Epinephrine Interaction (Severity Level: Major)
Potentiated the pharmacological effects (Unspecific) Click to Show/Hide Mechanism Graph
Drug Name		Timolol (ophthalmic)				Epinephrine
Mechanism		Enhance the pressor response to epinephrine				Epinephrine
Key Mechanism Factor 1
		Factor Name		Pharmacodynamics
		Factor Description		Enhanced pharmacological effects leading to increased adverse reactions.
Mechanism Description		Potentiate the pharmacologic effects by the combination of Epinephrine and Timolol (ophthalmic)

Recommended Action
Management		Extreme caution and close monitoring of cardiovascular status are indicated when epinephrine is administered to patients treated with noncardioselective beta-blockers. A dosage reduction of epinephrine may be necessary. Withdrawal of beta-blockers before anesthesia may increase the risk of myocardial ischemia and is not recommended. The interaction is not expected to occur with local anesthetics used in dental surgery that contain very low concentrations of epinephrine.

References
1	Spencer PS, Klein LE "Interaction of epinephrine and propranolol." J Am Acad Dermatol 14 (1986): 1093-4.[PMID: 3722489]
2	O'Grady J, Oh V, Turner P "Effects of propranolol and oxprenolol on the vasoconstrictor response to noradrenaline in the superficial hand vein in man." Eur J Clin Pharmacol 14 (1978): 83-5.[PMID: 720378]
3	Richards DA, Prichard BN, Hernandez R "Circulatory effects of noradrenaline and adrenaline before and after labetalol." Br J Clin Pharmacol 7 (1979): 371-8.[PMID: 444356]