Warfarin patients

Restricted contentYou mention in your article that there are several loading regimens, but it does not mention the adverse effect of high dose loading of warfarin. Warfarin inhibits proteins C and S, which are dependent on vitamin K. Protein C and S are natural anticoagulants.

Restricted contentFurther to the question by Sarah Bailey, does the recommendation to monitor INR four days after starting a short course of an interacting drug (eg, antibiotics) hold for patients in primary care or does this recommendation also apply to patients in hospital?

Restricted contentIn the PJ CPD article "Common concerns of warfarin patients", Frances Akinwunmi writes: "A number of classes of antibiotics affect INRs via a variety of mechanisms, more commonly resulting in an elevated INR.  If the response is predictable (eg, increased INR), proactive steps, such as missing a dose, may be recom

Restricted contentAs a general rule for warfarin patients prescribed antibiotics, should we be advising that they have their international normalised ratio checked four days after starting the antibiotic and then again four days after stopping? Would this be the same for all antibiotics, including those known to interact with warfarin (eg, ciprofloxacin)?

Sarah Bailey, Brecon, Powys

Restricted contentIf you have read Frances Akinwunmi article on common concerns of warfarin patients and have any questions about it, please send them to Ask the expert.