Drug Interaction Report
5 potential interactions and/or warnings found for the following 2 drugs:
- emtricitabine / tenofovir alafenamide
- famotidine / ibuprofen
Interactions between your drugs
ibuprofen tenofovir
Applies to: famotidine / ibuprofen, emtricitabine / tenofovir alafenamide
GENERALLY AVOID: Coadministration of tenofovir with other nephrotoxic agents may increase the risk of renal impairment due to additive effects on the kidney. Additionally, renal impairment secondary to the use of these agents may reduce the clearance of tenofovir, which is primarily eliminated by a combination of glomerular filtration and active tubular secretion. The use of tenofovir has been associated with dose-related nephrotoxicity including acute renal failure and Fanconi syndrome characterized by renal tubular injury with severe hypophosphatemia, possibly as a result of mitochondrial toxicity. Cases of acute renal failure after initiation of high-dose or multiple nonsteroidal anti-inflammatory agents have been reported in HIV-infected patients with risk factors for renal dysfunction who appeared stable on tenofovir therapy. Some patients required hospitalization and renal replacement therapy. Available clinical data seem to suggest a lower risk of nephrotoxicity with tenofovir alafenamide fumarate (TAF) than with tenofovir disoproxil fumarate (TDF), presumably due to lower tenofovir systemic exposure following administration of TAF relative to TDF. Whereas TDF is metabolized in plasma to tenofovir and phosphorylated intracellularly to the active moiety tenofovir diphosphate, TAF is largely metabolized and phosphorylated intracellularly, resulting in substantially higher intracellular concentrations of tenofovir diphosphate and lower plasma levels of tenofovir at the therapeutic dose of 25 mg compared to TDF 300 mg. It has been further reported that tenofovir is actively transported into the proximal renal tubular cell by organic anion transporters (OAT) 1 and 3, but that TAF is not a substrate for these transporters and thus less likely to cause tubular injury. There have been no cases of Fanconi syndrome or proximal renal tubulopathy in clinical trials of various TAF-containing products according to the manufacturers.
MANAGEMENT: The use of tenofovir in patients who have recently received or are receiving treatment with other potentially nephrotoxic agents (e.g., aminoglycosides; polypeptide, glycopeptide, and polymyxin antibiotics; amphotericin B; aminosalicylates; antiviral agents such as acyclovir, adefovir, cidofovir, foscarnet, and ganciclovir; antineoplastics such as aldesleukin, cisplatin, clofarabine, ifosfamide, streptozocin, and high intravenous dosages of methotrexate; chelating agents such as deferasirox, deferoxamine, edetate disodium, and edetate calcium disodium; immunosuppressants such as cyclosporine, everolimus, sirolimus, and tacrolimus; intravenous bisphosphonates; intravenous pentamidine; high dosages and/or chronic use of nonsteroidal anti-inflammatory agents; gallium nitrate; lithium; penicillamine) should be avoided if possible. Renal function tests including serum creatinine, serum phosphorous, estimated creatinine clearance, urine glucose, and urine protein should be performed prior to and during therapy with tenofovir. Patients with renal insufficiency at baseline or during treatment may require dosage adjustment in accordance with the manufacturer's product labeling. Persistent or worsening bone pain, pain in extremities, fractures, and/or muscular pain or weakness may also be manifestations of proximal renal tubulopathy and should prompt an evaluation of renal function in at-risk patients.
References
- (2001) "Product Information. Viread (tenofovir)." Gilead Sciences
- (2004) "Product Information. Truvada (emtricitabine-tenofovir)." Gilead Sciences
- (2015) "Product Information. Genvoya (cobicistat/elvitegravir/emtricitabine/tenofov)." Gilead Sciences
- (2016) "Product Information. Odefsey (emtricitabine/rilpivirine/tenofovir)." Gilead Sciences
- (2016) "Product Information. Descovy (emtricitabine-tenofovir)." Gilead Sciences
- (2017) "Product Information. Vemlidy (tenofovir)." Gilead Sciences
- Wang H, Lu X, Yang X, Xu N (2016) "The efficacy and safety of tenofovir alafenamide versus tenofovir disoproxil fumarate in antiretroviral regimens for HIV-1 therapy: Meta-analysis." Medicine (Baltimore), 95, e5146
- Sax PE, Zolopa A, Brar A, et al. (2014) "Tenofovir alafenamide vs. tenofovir disoproxil fumarate in single tablet regimens for initial HIV-1 therapy: a randomized phase 2 study." J Acquir Immune Defic Syndr, 67, p. 52-8
ibuprofen famotidine
Applies to: famotidine / ibuprofen, famotidine / ibuprofen
H2 antagonists may alter the disposition of nonsteroidal anti-inflammatory drugs (NSAIDs), resulting in increased or decreased plasma concentrations. Data are varied, even for the same NSAID. The mechanism may be related to inhibition of metabolism, changes in gastric pH that decrease absorption, and/or reduced urinary elimination. Statistically significant changes have been small and of limited clinical significance. Clinical monitoring of patient response and tolerance is recommended.
References
- Said SA, Foda AM (1989) "Influence of cimetidine on the pharmacokinetics of piroxicam in rat and man." Arzneimittelforschung, 39, p. 790-2
- Scavone JM, Greenblatt DJ, Matlis R, Harmatz JS (1986) "Interaction of oxaprozin with acetaminophen, cimetidine, and ranitidine." Eur J Clin Pharmacol, 31, p. 371-4
- (2001) "Product Information. Daypro (oxaprozin)." Searle
Drug and food interactions
ibuprofen food
Applies to: famotidine / ibuprofen
GENERALLY AVOID: The concurrent use of aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) and ethanol may lead to gastrointestinal (GI) blood loss. The mechanism may be due to a combined local effect as well as inhibition of prostaglandins leading to decreased integrity of the GI lining.
MANAGEMENT: Patients should be counseled on this potential interaction and advised to refrain from alcohol consumption while taking aspirin or NSAIDs.
References
- (2002) "Product Information. Motrin (ibuprofen)." Pharmacia and Upjohn
tenofovir food
Applies to: emtricitabine / tenofovir alafenamide
Food enhances the oral absorption and bioavailability of tenofovir, the active entity of tenofovir disoproxil fumarate. According to the product labeling, administration of the drug following a high-fat meal increased the mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of tenofovir by approximately 14% and 40%, respectively, compared to administration in the fasting state. However, administration with a light meal did not significantly affect the pharmacokinetics of tenofovir compared to administration in the fasting state. Food delays the time to reach tenofovir Cmax by approximately 1 hour. Tenofovir disoproxil fumarate may be administered without regard to meals.
References
- (2001) "Product Information. Viread (tenofovir)." Gilead Sciences
famotidine food
Applies to: famotidine / ibuprofen
H2 antagonists may reduce the clearance of nicotine. Cimetidine, 600 mg given twice a day for two days, reduced clearance of an intravenous nicotine dose by 30%. Ranitidine, 300 mg given twice a day for two days, reduced clearance by 10%. The clinical significance of this interaction is not known. Patients should be monitored for increased nicotine effects when using the patches or gum for smoking cessation and dosage adjustments should be made as appropriate.
References
- Bendayan R, Sullivan JT, Shaw C, Frecker RC, Sellers EM (1990) "Effect of cimetidine and ranitidine on the hepatic and renal elimination of nicotine in humans." Eur J Clin Pharmacol, 38, p. 165-9
Therapeutic duplication warnings
No duplication warnings were found for your selected drugs.
Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.
Drug Interaction Classification
Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit. | |
Moderately clinically significant. Usually avoid combinations; use it only under special circumstances. | |
Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan. | |
No interaction information available. |
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