Many discrepancies were found between different information sources at patient discharge from hospital. A majority of the discrepancies had their origin in hospital information. The number of medicines after discharge was related to the number of discrepancies found. The medication reconciliation process took an average of 45 minutes per patient.

NSAIDs are reported to increase the risk of bleeding in coumarin users. The mechanism underlying this risk is inhibition of platelet aggregation, however a pharmacokinetic mechanism resulting in an increased International Normalised Ratio (INR) was proposed in some case reports in warfarin treated patients. In this retrospective cohort study the influence of diclofenac, naproxen and ibuprofen on the INR of outpatients stabilised on acenocoumarol therapy was investigated. We also determined the role of cytochrome P450 2C9 (CYP2C9) polymorphism on coumarin dosage and INR in NSAID users. The study was carried out at the Groningen Outpatient Thrombosis Service. A retrospective cohort study among patients who received both acenocoumarol and one of the NSAIDs under study was performed. Patients whose INR rose above the upper level of the therapeutic range (INR above 3.5 or 4.0) after an NSAID under study was added to the acenocoumarol therapy, were compared with patients who did not show such an elevation. A two-sample t-test (average acenocoumarol dosage, age), and chi-square tests (sex, therapeutic range, type of NSAID) were used to test for differences. Genotyping was carried out by analysing blood samples for the relevant CYP2C9 alleles. The study population consisted of 112 patients on stable acenocoumarol therapy, of which 52 (46%) showed an elevation of the INR above the desired therapeutic level (INR 3.5 and 4.0 respectively) after the start of an NSAID under study. In 12 patients, the INR increased above 6. The INR of the other 60 patients (54%) remained constant after the start of one of the NSAIDs under study. There were no statistically significant differences between patients with increased INR and patients without increased INR with regard to age, sex, therapeutic range and average acenocoumarol dosage. Eighty patients, of whom 36 showed an increased INR as a result of a potential acenocoumarol-NSAID drug interaction, were included in the genotyping study. No association between CYP2C9 genotype and an increased INR as a result of the drug-drug interaction was found. In nearly half of a cohort of elderly patients, the INR increased beyond the therapeutic range (INR 3.5 or 4.0) as a result of a potential pharmacokinetic drug-drug interaction between acenocoumarol and diclofenac, naproxen and ibuprofen. The average increase in INR was between 1 and 4. Polymorphism of CYP2C9 does not seem to be a relevant risk factor for the NSAID-acenocoumarol interaction.

Background Direct oral anticoagulants (DOACs) are the preferred anticoagulants for thromboprophylaxis in atrial fibrillation. We aimed to identify determinants of quality of life related to DOAC treatment to optimize DOAC treatment convenience and satisfaction. Methods We conducted a cross‐sectional study in DOAC users. DOAC treatment–related convenience and satisfaction were measured by Perception of Anticoagulant Treatment Questionnaire. Higher scores are more favorable (range, 0‐100). Patient‐reported outcome measures and drug‐ and organization‐related factors were collected. Multiple regression analyses were used to evaluate the association between these factors (ie, exposure variables) and DOAC treatment–related convenience and treatment satisfaction (ie, outcome variables). Results Of 1598 patients invited, 1035 responded, and 962 were included. The median convenience score was 98.1 (94.2‐100.0), mean satisfaction score 66.5± 14.9. Twenty‐four percent felt not well informed at the start of DOAC; 6.9% did not know who to turn to with questions. Multiple regression analyses showed that lacking sense of security, the predefined composite of receiving insufficient information at start of DOAC and/or not knowing who to turn to with questions was associated with lower convenience (regression coefficient, −1.29; 95% confidence interval [CI], −2.16 to −0.41). Bleeding, gastrointestinal complaints, and lower medication adherence were also associated with lower convenience. Missing sense of security (regression coefficient −6.59; 95% CI, −8.94 to −4.24) and bleeding without consultation were associated with lower treatment satisfaction. Conclusions Accessible interventions to improve DOAC care could be providing more instruction at treatment initiation and ensuring that patients know who to contact in case of problems.