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NCT Number: NCT00603317

Pharmacodynamic Drug Interaction Between Warfarin and Amoxicillin-clavulanic Acid

Several case reports indicate that the use of the antibiotic combination amoxicillin and clavulanic acid (AM-CLAVAC) can interact with warfarin pharmacodynamics. However, fever per se might also be responsible of these warfarin overdose reports, as well as the use of high dose paracetamol.

The aim of the present study is to determine if AM-CLAVAC can increase the pharmacodynamics of warfarin among patients at steady state Double blinded cross over controlled study vs placebo performed in 12 evaluable patients treated with warfarin with an INR target 2 to 3 and a stable INR and a stable dose.

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Key information

Conditions

Oral Anticoagulation Arrhythmias, Cardiac Atrial Fibrillation Cardiovascular Diseases Deep Venous Thrombosis Embolism Embolism and Thrombosis Heart Diseases Lung Diseases Pathologic Processes Pathological Conditions, Signs and Symptoms Pulmonary Embolism Respiratory Tract Diseases Thrombosis Vascular Diseases Venous Thrombosis

Age range

18 year–80 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Primary location

Hopital Lariboisière - Service de médecine interne

Paris, 75475, France

About this study

Double blinded cross over controlled study vs placebo performed in 12 evaluable patients treated with warfarin with an INR target 2 to 3 and a stable INR and a stable dose

One period : seven consecutive days of amoxicillin(2g twice daily)- clavulanic acid (125 mg twice daily) association Wash out period of at least 4 weak with the return to a stable INR and warfarin dose One period : seven consecutive days of placebo twice daily

Main outcome INR delta Day7-Day

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • patients treated with warfarin (target INR 2 to 3)
  • stable anticoagulation (3 consecutive INR in the target)
  • stable dose
  • no infection
  • normal CRP
  • age >18 years
  • normal transaminase levels

Exclusion criteria

  • drug allergy
  • penicillin allergy
  • Alzheimer
  • cancer
  • thyroid disease
  • gastro intestinal chronic disease
  • frequent nausea or vomiting
  • Cirrhosis
  • chronic renal failure (GFR<60 ml/min)
  • frequent intake of paracetamol or NSAID
  • addict to drugs or alcool
  • St John's wort treatment or grapefruit juice intake
  • concomitant drugs (amiodarone, cimetidine, SSRI, clofibrate, fenofibrate, diltiazem, fluconazole, itraconazole, isoniazide, voriconazole, métronidazole, miconazole , omeprazole, glucocorticoids, zileuton, ritonavir, rifampicin, carbamazepine, phenytoin, phenobarbital)
  • antibiotic use during the 3 last weeks
  • pregnancy

Treatment and study plan

Firstly : Amoxicillin-Clavulanic acid and secondly : Placebo

Drug

Amoxicillin : 2g twice daily Clavulanic acid : 125 mg twice daily

Firstly : Placebo and secondly : Amoxicillin-Clavulanic acid

Drug

Amoxicillin : 2g twice daily Clavulanic acid : 125mg twice daily seven consecutive days

Primary outcomes

  1. INR at day one and seven (delta Day7-Day1)

    Time frame: 7 days

Secondary outcomes

  1. % of patients with an INR>3.5 during each study period mean INR during each study period effect of VKORC1 genetic polymorphism trough blood concentrations of S and R warfarin at day1 and day7 (delta) during each study period

    Time frame: 7 days for each period

Sponsors and collaborators

Lead sponsor

Assistance Publique - Hôpitaux de Paris

Other

Registry information

Acronym: INWARA

Important dates

Study start
2008
Primary completion
2010
Study completion
2010
First posted
Jan 29, 2008
Registry last updated
Jul 12, 2010

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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