Drug General Information (ID: DDI8PMTCK3)
Drug Name			Calcium carbonate		Drug Info		Raltegravir		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antacids/Minerals And Electrolytes				Antiviral Agents
Structure

Mechanism of Calcium carbonate-Raltegravir Interaction (Severity Level: Major)
Complex formation Click to Show/Hide Mechanism Graph
Drug Name		Calcium carbonate				Raltegravir
Mechanism		Polyvalent cations				Binds to polyvalent cations
Key Mechanism Factor 1
		Factor Name		Chelation
		Factor Description		Chelation is a direct drug interaction that usually involves the formation of dimers or trimers, resulting in larger complexes and poorer absorption.
Mechanism Description		Decreased absorption of Calcium carbonate due to formation of complexes caused by Raltegravir

Recommended Action
Management		Concomitant use of raltegravir with aluminum- and/or magnesium-containing antacids should generally be avoided, even if administration is staggered. Antacids containing calcium carbonate should not be used with once-daily raltegravir (HD formulation), but may be used without dose adjustment for other raltegravir products.

References
1	Canadian Pharmacists Association.
2	Cerner Multum, Inc. "Australian Product Information.".
3	Cerner Multum, Inc. "UK Summary of Product Characteristics.".
4	Kiser JJ, Bumpass JB, Meditz AL, et al. "Effect of antacids on the pharmacokinetics of raltegravir in human immunodeficiency virus seronegative volunteers." Antimicrob Agents Chemother 54 (2010): 4999-5003. [PMID: 20921313]
5	Moss DM, Siccardi M, Murphy M, et al. "Divalent metals and pH alter raltegravir disposition in vitro." Antimicrob Agents Chemother 56 (2012): 3020-6. [PMID: 22450971]
6	Product Information. Isentress (raltegravir). Merck & Company Inc, West Point, PA.
7	Roberts JL, Kiser JJ, Hindman JT, Meditz AL "Virologic failure with a raltegravir-containing antiretroviral regimen and concomitant calcium administration." Pharmacotherapy 31 (2011): 298e-302e.