Warfarin ⇔ amoxicillin Moderate Drug Interaction Applies to: Coumadin (warfarin) and amoxicillin MONITOR: Penicillins may occasionally potentiate the risk of bleeding in patients treated with oral anticoagulants. The exact mechanism of interaction is unknown but may involve penicillin inhibition of platelet aggregation. In one study, defective platelet aggregation occurred with predictability in patients receiving penicillin G 24 million units/day, ampicillin 300 mg/kg/day, and methicillin 300 mg/kg/day. Other penicillins such as nafcillin, piperacillin, and ticarcillin have also been found to affect platelet function, and benzylpenicillin and carbenicillin have been reported to increase bleeding times and cause bleeding in the absence of an anticoagulant. There have been case reports describing increases in prothrombin time and INR as well as spontaneous bruising and bleeding in anticoagulated patients following initiation or completion of penicillin therapy. Although most cases have involved large, intravenous doses of some penicillins (e.g., carbenicillin, penicillin G, ticarcillin), the interaction has also been reported with regular, oral doses of amoxicillin and amoxicillin-clavulanate. In fact, a case-control study found amoxicillin-clavulanate to be one of only two medications to significantly increase the risk of overanticoagulation in previously stable outpatients treated with phenprocoumon or acenocoumarol. Amoxicillin is a penicillin antibiotic treatment for a wide range of bacterial infections such as bronchitis, pneumonia and tonsillitis, as well as infections of the ear, nose, throat and urinary tract. It is also commonly used in associations with other antibiotics. I have had a history of nocturnal seizures- but was under control- ( have associated it with hot flashes/menapause) - When I woke up after seizure was flushed and warm. Now I am done with the prednisone- feel back to myself- with no issues- I believe the dose was too high- and abruptly stopping did not help the situation. the doctors seemed to not pay attention to my concerns. I also take..., Augmentin My period is late and this is a problem for me as I am getting married next Sunday (27th Match) and for religious reasons, I CANNOT be menstruating at that time (jewish religion). My period is about a week late but it is the first... Fluconazole half life Best place to buy viagra forum Prednisone how does it work Propecia for life To investigate whether an interaction exists between amoxicillin/clavulanic acid amoxiclav and warfarin in patients treated with stable oral anticoagulant. Download Citation on ResearchGate Warfarin and Amoxicillin/Clavulanate Drug Interaction To report a case of warfarin-amoxicillin/clavulanate potassium. Can I take Amoxicillin with Warfarin? There is a moderate interaction between Amoxicillin and Warfarin. You may want to consider another combination. Other drugs that can cause similar and clinically important interactions with warfarin are amiodarone, propafenone, and three antifungals that can be a problem at high doses but not with single doses – ketoconazole/fluconazole, itraconazole, or metronidazole. As for acetaminophen, "we always think of acetaminophen as a safe drug, but if you take enough of it – like three extrastrength Tylenol a day it can affect the INR," he said. adults are hospitalized for drug interaction is an interaction with warfarin, so watch out for some of the main culprits: trimethoprim/sulfamethoxazole, acetaminophen, and oral steroids, advised Dr. Paauw said, and was responsible for nearly three times the number of hospitalizations for drug interactions as any of the runner-ups – insulin, oral antiplatelet drugs, or oral hypoglycemics (N. "Trimethoprim/sulfamethoxazole has had a resurgence because of MRSA [methicillin-resistant Staphylococcus aureus]" infection. To treat a urinary tract infection in an anticoagulated patient, try not to use trimethoprim/sulfamethoxazole, and be worried about using quinolones, Dr. Penicillins/cephalosporins are acceptable, or use nitrofurantoin, he said. "The biggest, most serious interaction we’re going to stumble into with warfarin" is with trimethoprim/sulfamethoxazole, he said at the annual meeting of the American College of Physicians. Warfarin led the four drug classes that caused 67% of "the mayhem," Dr. Paauw, professor of medicine at the University of Washington, Seattle. adults older than 65 years were hospitalized per year in 2007-2009 because of drug interactions, according to a study of data from the National Electronic Injury Surveillance System’s Cooperative Adverse Drug Event Surveillance Project. So can erythromycin, which "we don’t use much any more," said Dr. Trimethoprim/sulfamethoxazole can decrease metabolism and increase prothrombin times in patients on warfarin. Drugs that possibly can interact with warfarin, especially in elderly patients and those on multiple medications, include quinolones, omeprazole, clarithromycin, and azithromycin. Be aware of this, and if a patient on warfarin is taking acetaminophen regularly, check the INR more often than you normally would, he added. One retrospective study of 104 patients on stable warfarin therapy found mean increases in the international normalized ratio (INR) of 1.76 in patients who also took trimethoprim/sulfamethoxazole, 0.85 with levofloxacin, and 0.51 with azithromycin, compared with a decrease of 0.15 in patients on terazosin, who served as a control group. Paauw said, is that the INR increased beyond therapeutic levels in 69% of patients on warfarin plus trimethoprim/sulfamethoxazole, 33% of patients on warfarin plus levofloxacin, 31% on warfarin and azithromycin, or 5% on warfarin and terazosin (J. Findings from three studies suggest there are INR effects from interactions of warfarin and acetaminophen. Horn and Hansten are both professors of pharmacy at the University of Washington School of Pharmacy. For an electronic version of this article, including references if any, visit We discussed the role of antibiotics that inhibit the metabolism of warfarin, primarily inhibitors of the cytochrome P (CYP) 450 enzyme CYP2C9, such as fluconazole (Diflucan) and sulfamethoxazole/trimethoprim (Bactrim). These antibiotics can predictably inhibit warfarin clearance and cause hypoprothrombinemia. In addition, many other antibiotics have been noted in case reports to be associated with elevated international normalized ratio (INR) values in patients taking warfarin. In our previous review, we summarized data showing that the infection itself can affect warfarin metabolism leading to higher INR values. The mechanism appears to be via stimulation of the immune system, resulting in secretion of proinflammatory cytokines, such as tumor necrosis factor and interleukin. This intrinsic inhibition of warfarin metabolism combined with dietary changes (reduced vitamin K intake) often associated with bacterial or viral infections may account for the reported increases in INR noted in the antibiotic–warfarin case reports. Amoxicillin warfarin interaction Table 1 – Antibiotic Class Interactions with Warfarin, Warfarin and Amoxicillin/Clavulanate Drug Where can i buy retin a microMetformin yeast infectionSildenafil hypotension Several case reports indicate that the use of the antibiotic combination amoxicillin and clavulanic acid AM-CLAVAC can interact with warfarin. Pharmacodynamic Drug Interaction Between Warfarin and Amoxicillin.. Amoxicillin and Warfarin interaction Treato. Amoxicillin/clavulanic acid-warfarin drug. OBJECTIVETo report a case of warfarin–amoxicillin/clavulanate potassium AM/CL interaction resulting in an elevated international normalized ratio INR. Can I take Amoxicillin with Warfarin? There is a moderate interaction between Amoxicillin and Warfarin. You may want to consider another combination. - Page 3 Amoxicillin potentially alters the anticoagulant effect of warfarin. Manufacturer advises monitor INR and adjust dose.