From the Research
Warfarin is typically administered at 4 PM because this timing allows for more effective monitoring and dose adjustments, which is crucial in minimizing the risk of bleeding complications and mortality, as supported by the study published in 2017 1. When warfarin is given in the afternoon, blood tests to measure its effect (INR levels) can be drawn in the morning, and any necessary dose adjustments can be made the same day before the next dose. This creates an efficient workflow for healthcare providers to review lab results and communicate changes to patients before they take their next dose. Some key points to consider when administering warfarin include:
- Establishing a consistent time like 4 PM helps patients develop a routine, improving medication adherence
- The afternoon timing also allows the medication to be taken with food if needed to reduce stomach upset, while avoiding the evening when patients might forget to take it if they become tired
- From a pharmacological perspective, the specific time of day is less important than taking warfarin consistently at the same time each day to maintain stable blood levels of the medication, as highlighted in the study published in 2019 2
- The risk of bleeding complications and mortality can be minimized by maintaining a high quality of warfarin treatment, with a low INR variability and a high individual time in therapeutic range (iTTR), as demonstrated in the study published in 2017 1
- Other studies, such as those published in 2011 3, 2013 4, and 2010 5, also emphasize the importance of careful management of warfarin therapy to minimize the risk of adverse events.