Drug General Information (ID: DDIU8YI04K)
Drug Name			Erythromycin		Drug Info		Zafirlukast		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antibiotics				Antiasthmatic Agents
Structure

Mechanism of Erythromycin-Zafirlukast Interaction (Severity Level: Moderate)
Increased renal excretion (Unspecific) Click to Show/Hide Mechanism Graph
Drug Name		Erythromycin				Zafirlukast
Mechanism		Decrease zafirlukast plasma concentrations				Zafirlukast
Key Mechanism Factor 1
		Factor Name		Pharmacokinetics
		Factor Description		Alters the excretion of the drug, resulting in changes in the plasma concentration of the drug and affecting the pharmacological effects.
Mechanism Description		Increased renal excretion of Zafirlukast caused by Erythromycin

Recommended Action
Management		The clinician should be aware of this interaction and observation for decreased zafirlukast efficacy is recommended if the combination is used.

References
1	Product Information. Accolate (zafirlukast). Zeneca Pharmaceuticals, Wilmington, DE.
2	Welling PG "Influence of food and diet on gastrointestinal drug absorption: a review." J Pharmacokinet Biopharm 5 (1977): 291-334.[PMID: 330836]
3	Welling PG, Huang H, Hewitt PF, Lyons LL "Bioavailability of erythromycin stearate: influence of food and fluid volume." J Pharm Sci 67 (1978): 764-6.[PMID: 660450]