Acute warfarin toxicity: An unanticipated consequence of amoxicillin/clavulanate administration
Timothy R Larsen1, Alehegn Gelaye1, Christopher Durando1
1Department of Internal Medicine, Providence Hospital and Medical Center, Southfield, MI, U.S.A.
Patient:
Male, 53 FINAL DIAGNOSIS: Acute Warfarin toxicity Symptoms: -
Medication:
Warfarin Clinical Procedure: - Specialty: Hematology.
Objective:
Unusual clinical course.
Background:
Warfarin remains the most common anticoagulant in the management of thromboembolic diseases. However, its extensive drug interaction requires frequent monitoring and dose adjustments. Almost all antibiotics, including penicillins, have the potential to interact with warfarin causing either under or over anticoagulation which increases the risk for thrombus formation and significant bleeding respectively.
Case Report:
A 53-year-old Caucasian male with a history of protein C deficiency and recurrent intravascular thrombosis developed a dental abscess. He was treated with amoxicillin/clavulanate 500/125 mg twice daily and referred to a dentist. He developed significant bleeding after tooth extraction. INR was 20.4. He received fresh frozen plasma and vitamin K with resolution of bleeding.
Conclusions:
While rare, clinically significant prolonged prothrombin time and potentially life threatening bleeding can occur when amoxicillin/clavulanate is concomitantly administered with warfarin. Prompt recognition and intervention is necessary to avoid life threatening complications from warfarin-amoxicillin/clavulanate interaction.
Insights
A rare but serious interaction between warfarin and amoxicillin/clavulanate can cause dangerous bleeding. This case highlights the need for careful monitoring when these medications are used together, especially after dental procedures.
Area of Science:
- Pharmacology
- Internal Medicine
- Hematology
Background:
- Warfarin is a common anticoagulant for thromboembolic diseases.
- Warfarin has numerous drug interactions requiring monitoring.
- Antibiotics can alter warfarin's effect, increasing risks of thrombosis or bleeding.
Purpose of the Study:
- To report an unusual clinical course of acute warfarin toxicity.
- To highlight a rare drug interaction between warfarin and amoxicillin/clavulanate.
Main Methods:
- A 53-year-old male with protein C deficiency and thrombosis history developed a dental abscess.
- Patient was treated with amoxicillin/clavulanate and underwent tooth extraction.
- Significant bleeding occurred post-extraction, with INR of 20.4.
Main Results:
- The patient experienced severe bleeding after tooth extraction while on amoxicillin/clavulanate and warfarin.
- International Normalized Ratio (INR) was critically elevated at 20.4.
- Treatment with fresh frozen plasma and vitamin K resolved the bleeding.
Conclusions:
- Concomitant use of amoxicillin/clavulanate and warfarin can lead to prolonged prothrombin time and life-threatening bleeding.
- Prompt recognition and intervention are crucial for managing this rare but severe drug interaction.
- This interaction underscores the importance of vigilant patient monitoring.
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