Itraconazole; Ketoconazole/Agents Affecting Gastric pH Interactions
This information is generalized and not intended as specific medical advice. Consult your healthcare professional before taking or discontinuing any drug or commencing any course of treatment.
Moderate. These medicines may cause some risk when taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.
How the interaction occurs:
Your antifungal medicine is absorbed the best in an acidic environment. Your other medicine decreases the amount of acid in your stomach.
What might happen:
A decrease in the beneficial effects of your antifungal medicine may occur.
What you should do about this interaction:
Contact your healthcare professionals (e.g. doctor or pharmacist) as soon as possible about taking these two medicines together. They may already be aware of this interaction and may be monitoring you for it. If your doctor prescribes these medicines together, you may need to take another medicine before taking your antifungal. Try to take your antifungal medicine at least 2 hours before taking your other medicine. Do not start, stop, or change the dosage of any medicine before checking with them first.
- 1.Prilosec (omeprazole) US prescribing information. AstraZeneca Pharmaceuticals LP December, 2014.
- 2.Prevacid (lansoprazole) US prescribing information. Takeda Pharmaceuticals America, Inc. December, 2015.
- 3.Van Der Meer JW, Keuning JJ, Scheijgrond HW, Heykants J, Van Cutsem J, Brugmans J. The influence of gastric acidity on the bio-availability of ketoconazole. J Antimicrob Chemother 1980 Jul;6(4):552-4.
- 4.Carlson JA, Mann HJ, Canafax DM. Effect of pH on disintegration and dissolution of ketoconazole tablets. Am J Hosp Pharm 1983 Aug; 40(8):1334-6.
- 5.Jaruratanasirikul S, Sriwiriyajan S. Effect of omeprazole on the pharmacokinetics of itraconazole. Eur J Clin Pharmacol 1998 Apr; 54(2):159-61.
- 6.Johnson MD, Hamilton CD, Drew RH, Sanders LL, Pennick GJ, Perfect JR. A randomized comparative study to determine the effect of omeprazole on the peak serum concentration of itraconazole oral solution. J Antimicrob Chemother 2003 Feb;51(2):453-7.
- 7.Chin TW, Loeb M, Fong IW. Effects of an acidic beverage (Coca-Cola) on absorption of ketoconazole. Antimicrob Agents Chemother 1995 Aug; 39(8):1671-5.
- 8.Zimmermann T, Yeates RA, Riedel KD, Lach P, Laufen H. The influence of gastric pH on the pharmacokinetics of fluconazole: the effect of omeprazole. Int J Clin Pharmacol Ther 1994 Sep;32(9):491-6.
- 9.Wood N, Tan K, Purkins L, Layton G, Hamlin J, Kleinermans D, Nichols D. Effect of omeprazole on the steady-state pharmacokinetics of voriconazole. Br J Clin Pharmacol 2003 Dec;56 Suppl 1:56-61.
- 10.Lelawongs P, Barone JA, Colaizzi JL, Hsuan AT, Mechlinski W, Legendre R, Guarnieri J. Effect of food and gastric acidity on absorption of orally administered ketoconazole. Clin Pharm 1988 Mar;7(3):228-35.
- 11.Lazar JD, Wilner KD. Drug interactions with fluconazole. Rev Infect Dis 1990 Mar-Apr;12 Suppl 3:S327-33.
- 12.Piscitelli SC, Goss TF, Wilton JH, D'Andrea DT, Goldstein H, Schentag JJ. Effects of ranitidine and sucralfate on ketoconazole bioavailability. Antimicrob Agents Chemother 1991 Sep;35(9):1765-71.
- 13.Lim SG, Sawyerr AM, Hudson M, Sercombe J, Pounder RE. Short report: the absorption of fluconazole and itraconazole under conditions of low intragastric acidity. Aliment Pharmacol Ther 1993 Jun;7(3):317-21.
- 14.Tagamet (cimetidine) US prescribing information. GlaxoSmithKline December, 2005.
- 15.Lohitnavy M, Lohitnavy O, Thangkeattiyanon O, Srichai W. Reduced oral itraconazole bioavailability by antacid suspension. J Clin Pharm Ther 2005 Jun;30(3):201-6.
- 16.Moreno F, Hardin TC, Rinaldi MG, Graybill JR. Itraconazole-didanosine excipient interaction. JAMA 1993 Mar 24-31;269(12):1508.
- 17.Brass C, Galgiani JN, Blaschke TF, Defelice R, O'Reilly RA, Stevens DA. Disposition of ketoconazole, an oral antifungal, in humans. Antimicrob Agents Chemother 1982 Jan;21(1):151-8.
- 18.Thorpe JE, Baker N, Bromet-Petit M. Effect of oral antacid administration on the pharmacokinetics of oral fluconazole. Antimicrob Agents Chemother 1990 Oct;34(10):2032-3.
- 19.May DB, Drew RH, Yedinak KC, Bartlett JA. Effect of simultaneous didanosine administration on itraconazole absorption in healthy volunteers. Pharmacotherapy 1994 Sep-Oct;14(5):509-13.
- 20.Knupp CA, Brater DC, Relue J, Barbhaiya RH. Pharmacokinetics of didanosine and ketoconazole after coadministration to patients seropositive for the human immunodeficiency virus. J Clin Pharmacol 1993 Oct;33(10):912-7.
- 21.Damle BD, Mummaneni V, Kaul S, Knupp C. Lack of effect of simultaneously administered didanosine encapsulated enteric bead formulation (Videx EC) on oral absorption of indinavir, ketoconazole, or ciprofloxacin. Antimicrob Agents Chemother 2002 Feb;46(2):385-91.
- 22.Phansalkar S, van der Sijs H, Tucker AD, Desai AA, Bell DS, Teich JM, Middleton B, Bates DW. Drug-drug interactions that should be non-interruptive in order to reduce alert fatigue in electronic health records. J Am Med Inform Assoc 2012 Sep 25.
CONDITIONS OF USE: The information in this database is intended to supplement, not substitute for, the expertise and judgment of healthcare professionals. The information is not intended to cover all possible uses, directions, precautions, drug interactions or adverse effects, nor should it be construed to indicate that use of a particular drug is safe, appropriate or effective for you or anyone else. A healthcare professional should be consulted before taking any drug, changing any diet or commencing or discontinuing any course of treatment.