Evaluation of Maintenance Dosing vs Loading Dosing Upon Restarting Warfarin Therapy: A Prospective Randomized Trial

Anticoagulation Clinical Trial

Official title:

Evaluation of Maintenance Dosing vs Loading Dosing Upon Restarting Warfarin Therapy: A Prospective Randomized Trial.

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01124058
• Other study ID #: 2007UHFMDvsLD
• Status: Completed
• Phase: Phase 1
• First received: May 13, 2010
• Last updated: October 24, 2017
• Start date: July 2010
• Est. completion date: August 2012

Study information

• Verified date: October 2017
• Source: University of Alberta
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

A prospective, randomized trial to compare the time taken to achieve a therapeutic INR upon re-starting warfarin at a "loading" dose (namely 1.5 times the "maintenance" dose for 3 days) compared to the known "maintenance" dose.

Description:

Patients will be identified via the University of Alberta Hospital Anticoagulation Management Service. Following the receipt of written, informed consent, patients will be randomized to re-start warfarin at their "maintenance" dose or at a "loading" dose (1.5 times the maintenance dose for 3 days, then resumption of warfarin dosing as per the maintenance dose). Randomization will be performed on-line through the EPICORE Centre.

Assuming Day 1 is the day warfarin is re-started, patients will have INRs done on day 3 and at least every 2 days thereafter until a therapeutic INR is obtained. In addition, protein C, protein S and factor II levels will be obtained while the patient is on stable maintenance dosing of warfarin (i.e., prior to holding warfarin for the procedure), 7 days after re-starting warfarin, and 14 days after re-starting warfarin. Complete blood counts (CBCs) will be done with each INR if the patient is taking a low molecular weight heparin (LMWH). Patients will have their anticoagulant therapy managed by the AMS for 6 weeks and will receive a telephone follow-up by the AMS at 90 days to determine if any bleeding or clotting complications occurred.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 39
• Est. completion date: August 2012
• Est. primary completion date: August 2012
• Accepts healthy volunteers: No
• Gender: All
• Age group: 18 Years and older

Eligibility

Inclusion Criteria:

• Have 'stable warfarin maintenance dosing' (defined as last 2 INRs within therapeutic range with weekly warfarin dosing not being changed any more than 10%)

• Have an INR indicative of not taking any warfarin (INR <1.4) or confirmation of the patient not taking any warfarin in the past 4 days

• Provide written, informed consent

Related Conditions & MeSH terms

• Anticoagulation

Intervention

Drug:
• warfarin
Patients will be randomized to re-start warfarin at their "maintenance" dose or at a "loading" dose (1.5 times the maintenance dose for 3 days, then resumption of warfarin dosing as per the maintenance dose).
• Warfarin
"Maintenance" dose is the amount of warfarin that a patient required to maintain a therapeutic INR.

Locations

Country	Name	City	State
Canada	Univeristy of Alberta	Edmonton	Alberta

Sponsors (1)

Lead Sponsor	Collaborator
University of Alberta

Country where clinical trial is conducted

Canada, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	re-starting warfarin "loading" dose vs "maintenance" dose	To compare the time taken to achieve a therapeutic INR between those patients re-starting warfarin with a "loading" dose and a "maintenance" dosing regimen using linear interpolation of INRs.	INR drawn 3 days post-reinitiation and then every 2 days until therapeutic
Secondary	Compare % of time within, above and below the target INR range	To compare the % of time within, above and below the desired INR range between those patients re-starting warfarin with a "loading" dose or "maintenance" dose 6 weeks following restarting warfarin.	days
Secondary	Compare bleeding/clotting complications between two groups	To compare the rates of thrombosis (i.e., stroke) / major hemorrhage between those re-starting warfarin with a "loading" dose or "maintenance" dose at 30 days and 90 days following restarting warfarin.	30 days, 90 days
Secondary	Compare the levels of protein C, protein S, and factor II between 2 groups.	To compare the levels of protein C, protein S, and factor II between those re-starting warfarin with a "loading" dose or "maintenance" dose.	week