Drug General Information (ID: DDIZ7S6URI)
Drug Name			Erlotinib		Drug Info		Calcium carbonate		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antineoplastics				Antacids/Minerals And Electrolytes
Structure

Mechanism of Erlotinib-Calcium carbonate Interaction (Severity Level: Moderate)
Altered gastric pH Click to Show/Hide Mechanism Graph
Drug Name		Erlotinib				Calcium carbonate
Mechanism		Gastric pH sensitive				Gastric alkalinizer
Key Mechanism Factor 1
		Factor Name		Gastric pH
		Factor Description		The normal pH range of gastric acid is between 1.5 and 3.5 and is highly acidic, consisting mainly of hydrochloric acid. Changes in the pH of the stomach can alter the absorption of drugs.
Mechanism Description		Decreased absorption of Erlotinib due to altered gastric pH caused by Calcium carbonate

Recommended Action
Management		If an antacid or other agent with acid-neutralizing effects is required during erlotinib therapy, it should be administered at least 4 hours before or 2 hours after the daily dose of erlotinib.

References
1	Cerner Multum, Inc. "Australian Product Information.".
2	Cerner Multum, Inc. "UK Summary of Product Characteristics.".
3	Duong S, Leung M "Should the concomitant use of erlotinib and acid-reducing agents be avoided? The drug interaction between erlotinib and acid-reducing agents." J Oncol Pharm Pract 17 (2011): 448-52. [PMID: 20716581]
4	Product Information. Tarceva (erlotinib). Genentech, South San Francisco, CA.