Drug General Information (ID: DDI9L2408D)
Drug Name			Ranitidine		Drug Info		Itraconazole		Drug Info
Drug Type		Small molecule				Small molecule
Therapeutic Class		Antiulcer Agents				Antifungal Agents
Structure

Mechanism of Ranitidine-Itraconazole Interaction (Severity Level: Moderate)
Altered gastric pH Click to Show/Hide Mechanism Graph
Drug Name		Ranitidine				Itraconazole
Mechanism		Gastric alkalinizer				Gastric pH sensitive
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 Itraconazole due to altered gastric pH caused by Ranitidine

Recommended Action
Management		H2 antagonists should be taken at least 2 hours after itraconazole. If necessary, an acidic pH may be produced by administration with an acidic beverage such as Coca-Cola(R) or Pepsi(R). However, clinicians should still consider the possibility of a reduced or subtherapeutic antifungal effect. It may be appropriate to switch to itraconazole oral solution or an agent like fluconazole or terbinafine whose absorption is not affected by stomach pH.

References
1	Blum RA, D'Andrea DT, Florentino BM, et al "Increased gastric pH and the bioavailability of fluconazole and ketoconazole." Ann Intern Med 114 (1991): 755-7. [PMID: 2012358]
2	Katz HI "Drug interactions of the newer oral antifungal agents." Br J Dermatol 141 (1999): 26-32. [PMID: 10730911]
3	Lazar JD, Wilner KD "Drug interactions with fluconazole." Rev Infect Dis 12 Suppl 3 (1990): s327-33. [PMID: 2330488]
4	Product Information. Sporonox (itraconazole). Janssen Pharmaceutica, Titusville, NJ.