In vitro Bioaccessibility, Bioavailability, and Plasma Protein Interaction of New Oral Anticoagulants in the Presence of Macronutrients

Biopharmaceutics considerations for direct oral anticoagulants

Vitamin K antagonists (VKA) and direct oral anticoagulants (DOACs) have been clinically used in the treatment of coagulation disorders. There are four DOACs approved since 2010 (dabigatran etexilate, rivaroxaban, apixaban, and edoxaban), and they were designed to overcome the practical limitations of VKA. This review summarized biopharmaceutics considerations about DOACs, which are critically discussed, applying risk analyses to subside the further classification of these drugs according to the Biopharmaceutics Classification System (BCS). These discussions included data compiled about physicochemical properties, equilibrium solubility, permeability, and drug dissolution of DOACs. From the biopharmaceutics characteristics is possible to identify critical variables related to the absorption process, which can help in the design of new formulations. The data were compared with the criteria recommended by regulatory agencies for the biopharmaceutics classification according to the BCS. From that, these data may be used to discuss the approval of generic medicines by the BCS-based biowaiver, and the clinical risks arising from novel formulations with DOACs. However, although there are indications of biopharmaceutics classifications for DOACs, conclusive information to classify these compounds according to the BCS is lacking, requiring more experimental studies to achieve this aim. Conclusive information is essential for a safe decision about the biowaiver, as well as to guide the development of new formulations containing the DOACs.

The Clinical Significance of Drug-Food Interactions of Direct Oral Anticoagulants

Cardiovascular diseases are the most common cause of death in the world. For almost 60 years, vitamin K antagonists (VKAs) were the mainstay of anticoagulation therapy, but in recent years direct oral anticoagulants (DOACs) have become the anticoagulant treatment of choice. DOACs were initially considered drugs with no significant food interactions; however, clinical observations from daily practice have proved otherwise as interactions with food ingredients have been reported. Food, dietary supplements or herbs may contain substances that, when administered concomitantly with DOACs, can potentially affect the plasma concentration of the drugs. The aim of this paper was to evaluate the clinical significance of drug-food interactions of DOACs, such as dabigatran, rivaroxaban, apixaban, edoxaban and betrixaban. Patients treated with anticoagulants should avoid products containing St. John's wort and take special care with other food ingredients. As the interest in dietary supplements is on the rise, healthcare providers can contribute to the development of well-designed clinical trials on interactions between DOACs and food, and distribute sufficient knowledge about the proper use of these supplements among patients.

Factors associated with bleeding events in patients on rivaroxaban for non-valvular atrial fibrillation: A real-world experience

BACKGROUND

Rivaroxaban is a direct oral anticoagulant (DOAC) approved for the treatment of non-valvular atrial fibrillation (NVAF). Data related to the risk factors associated with rivaroxaban-induced bleeding in patients with NVAF remain scarce in the community setting. We sought to investigate these bleeding risk factors in a racially diverse patient population.

METHODS

We conducted a single-center, retrospective study based on a chart review of patients who received rivaroxaban from our outpatient pharmacy from January 2015 to April 2018 for NVAF. Any reported bleeding event (BE) was recorded as either major or minor bleeding event. Demographic and clinical data were collected and analyzed.

RESULTS

Of the 327 patients included in our analysis, 105 (32%) were female, and the mean age was 62 ± 12 years. Among the included patients, 176 (54%) patients were black, 71 (22%) were white, 51 (15.6%) were Hispanic, 13 (4%) were Asian, and 15 (4.6%) belonged to other races. 89 (27.2%) of the patients had co-prescription of aspirin. A total of 24 (7.3%) patients developed BE, out of which 9 (2.7%) patients had a major BE, and 15 (4.5%) patients had minor BE. Non-fatal gastrointestinal bleeding and epistaxis were the most common type of BE. On multivariable analysis, concurrent aspirin use (81 to 325 mg) (P = 0.03; odds ratio (OR) 2.60 [1.08-6.28]) and increasing age (P = 0.00; OR 1.06 [1.01-1.11]) were independent predictors of BE.

CONCLUSION

In community practice, aspirin co-prescription is common among NVAF patients prescribed rivaroxaban. Increasing age and concurrent aspirin use are independent predictors of BE.