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Drug interactions between cefaclor and warfarin

Results for the following 2 drugs:

Interactions between your drugs


warfarin ↔ cefaclor

Applies to:warfarin and cefaclor

Consumer information for this interaction is not currently available.

MONITOR: Cephalosporins may potentiate the anticoagulant effects of vitamin K antagonists. Possible mechanisms include inhibited growth of vitamin K-producing intestinal bacteria, inhibited production of vitamin K-dependent clotting factors via a methylthiotetrazole (MTT) side chain (e.g., cefamandole, cefmetazole, cefoperazone, cefotetan), and/or inhibited platelet activity. Decreased prothrombin activity has been reported during treatment with various cephalosporins. Risk factors include renal or hepatic impairment, poor nutritional state, protracted antimicrobial therapy, and chronic anticoagulation therapy.

MANAGEMENT: Prothrombin time and INR should be monitored and the patient closely observed for signs of bleeding. The anticoagulant dose may be adjusted as indicated. Patients should be advised to notify their physicians if they experience any signs or symptoms that may indicate excessive anticoagulation, such as unusual or prolonged bleeding, bruising, coffee ground emesis, change in stool or urine color, headache, dizziness, or weakness.


  1. "Product Information. Suprax (cefixime)." Lupin Pharmaceuticals Inc, Baltimore, MD.
  2. Wood T, Johnson K, Naylor S, Weinshilboum R "Cefazolin administration and 2-methyl-1,3,4-thiadiazole-5-thiol in human tissue: possible relationship to hypoprothrombinemia." Drug Metab Dispos 30 (2002): 1123-1128
  3. Cerner Multum, Inc. "Canadian Product Information." O 0 (2015):
View all 44 references

Drug Interaction Classification

The classifications below are a guideline only. The relevance of a particular drug interaction to a specific patient is difficult to determine using this tool alone given the large number of variables that may apply.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor 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.
Unknown No information available.

Do not stop taking any medications without consulting your healthcare provider.

Disclaimer: Every effort has been made to ensure that the information provided by Multum is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. Multum's information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill, knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate that the drug or combination is safe, effective, or appropriate for any given patient. Multum Information Services, Inc. does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. Copyright 2000-2017 Multum Information Services, Inc. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse, or pharmacist.