Background Vitamin K (VK), whose recommended daily intake is easily achieved by food, enteral or parenteral nutrition, is mainly indicated as an antidote against hypoprothrombinaemia due to excessive coumarin anticoagulation. It’s activity correlates with the international normalised ratio (INR), which is also influenced by other conditions affecting the extrinsic coagulation pathway (liver disease, intravascular diffuse coagulation, antiphospholipid syndrome). According to benchmarking data, VK expenses are 9 times higher than the country’s average.

Purpose Our aim was to assess if VK is being used according to the available clinical evidence, estimating the impact of unnecessary prescriptions and checking if pharmacists’ interventions could modify doctors’ prescription habits.

Material and methods We included all VK prescriptions written during July 2015, studying how posology evolved until treatment interruption or patient discharge. Gathered demographic and clinical data were coded in a Filemaker database, using SPSS 22 for statistical treatment. When necessary, by leaving a note in the patient’s history, doctors were required to make changes in order to fit clinical evidence.

Results 66 patients (47 male, average age 65.1 ± 17.2 years) received VK, emergencies being the area with the most prescriptions (16). Only 10 were signed by an haematologist. The main indication (anticoagulant hypoprothrombinaemia) had the lowest expense (204.05€) and better compliance with evidence (54.0% of the doses unnecessary). 1245.55€ were spent on management of malabsorption, liver disease and prolonged antibiotic use, poorly supported by evidence (78.7% doses unnecessary). We proved no correlation between VK dosing changes and INR evolution in a complex cirrhotic patient (Spearman’s rho, p > 0.05). Perioperative hypoprothrombinaemia (INR <1.5), commonly irrelevant, meant an expense of 731.40€ (93.5% unsupported uses). 1097.5€ were spent for unclear or inappropriate indications, such as intravascular coagulation or antiphospholipid syndrome. Pharmacists wrote 18 interventions, changing prescriptions in most cases (15).

Conclusion Unnecessary VK prescription, worrying because of its high incidence, has an important impact on health system budget (up to 34 000€ yearly if we extrapolate our results). Considering how pharmacists succeeded in optimising prescriptions, our conclusions will be presented to the next Pharmacy and Therapeutics Committee. We will remark on the main role of pharmacist intervention, and propose formative activities for doctors in order to improve VK prescription quality.

References and/or Acknowledgements 15 references.

No conflict of interest.