Abstract
Aims:
It is well documented that many herbal/health supplements (collectively referred as supplements) interact with warfarin. This research aimed to study the prevalence and intake of supplements by SingHealth Polyclinics patients on warfarin, and their knowledge of and perception towards potential supplements-warfarin interactions.
Methods:
One hundred SingHealth Polyclinics patients who were on warfarin were recruited from 4 polyclinics. Each patient was interviewed in person and completed a 6-part survey. The results of the survey were statistically analysed.
Results:
In this 3-month study, a significant 42% of the patients took supplements concurrently with warfarin. Traditional Chinese Medicines, glucosamine and omega-3 fatty acids were the 3 most common supplements consumed. Eighty-nine per cent of the patients were unable to verbalise the supplements that could interact with warfarin. Out of the 42 patients who were on supplements, 74% (31 out of 42) felt that it was important to inform their healthcare professionals with regards to their supplements use. However, 45% (14 out of 31) of them did not inform their healthcare professionals. The correlation between the importance attached by patients to inform healthcare professionals about their supplements intake and their actual decision to inform their healthcare professionals was significant (p=0.0122). Doctors, pharmacists and family members were their top 3 sources of information when they needed advice before their intake of supplements.
Conclusion:
Patients' concurrent intake of supplements without informing their healthcare professionals poses potential risk to their health. Healthcare professionals can play a significant role in advancing medication safety by educating these patients on the possibility of supplements-warfarin interactions and the risk of interference with anticoagulation therapy. This study also highlighted supplements on which further research could be done to determine their potential for interactions with warfarin.