Dosing of rivaroxaban by indication: getting the right dose for the patient

Development of immediate-release formulation with reliable absorption of rivaroxaban in various meal regimes

The bioavailability of rivaroxaban at the higher doses (15 and 20 mg) is considerably reduced when the drug is administered on an empty stomach. This can lead to inadequate anticoagulant effect, and therefore, it is recommended to use the higher doses at fed state. However, proper posology may represent a barrier for some patients. Therefore, the aim of this study was to evaluate innovative rivaroxaban-containing formulations designed to eliminate the food effect to ensure reliable absorption and thus to improve patient adherence with the treatment. Three prototypes (Cocrystal, HPMCP and Kollidon) with rivaroxaban were developed and their bioavailability and food effect in comparison to the reference product was tested in open label, randomized, single oral dose, crossover studies, where test products were administered under fasting and fed conditions and the reference product was administered under fed conditions. Comparable bioavailability for all tested prototypes both under fed and fasting conditions was demonstrated as the 90% confidence intervals of the geometric mean ratios for area under the concentration-time curve remained within the standard acceptance range of 80.00%-125.00%. An innovative immediate release form of rivaroxaban with no food effect on drug bioavailability has been developed, which may represent an important step toward increasing adherence, improving treatment outcome and reducing health care costs.

Knowledge is power: general practitioners prescribing of new oral anticoagulants in Ireland

OBJECTIVE

New oral anticoagulants (NOACs) aim to overcome warfarin's shortcomings, however their pharmacokinetic characteristics make prescribing complex. Thus it is imperative that general practitioners (GPs) are aware of specific treatments so as to maximise their benefits and minimise their pitfalls. This study explores GPs attitudes and experiences with prescribing NOACs in Ireland where, despite clear national prescribing guidelines advocating warfarin as first line therapy, the number of patients being prescribed NOACs for the first time is growing.

RESULTS

Using primary data collected from GPs in Ireland the factors influencing the likelihood of a GP initiating a prescription for a NOAC are determined using a probit model. Results indicate 46% of the sample initiated NOAC prescriptions and GP practice size is a significant factor influencing this. Analysis revealed no difference regarding the sources of information considered important amongst GPs when prescribing new drugs. However, there were differences in which factors were considered important when prescribing anticoagulants between initiating and non-initiating NOAC prescribers. The results of this study suggest better utilisation of existing information and education tools for GPs prescribing NOACs and managing NOAC patients is imperative, to ensure the right anticoagulant is prescribed for the right patient at the right time.

New Oral Anaticoagulant Prescribing Decisions amongst General Practitioners: Handle with Care

Background: Prescribing oral anticoagulants for atrial fibrillation patients is becoming more challenging as more alternatives enter the market. While warfarin has dominated the market it is a challenging medicine to use owing to its narrow therapeutic range, increased bleeding risk and requirement for continuous monitoring. The introduction of new oral anticoagulants (NOACs) offers a wider choice but they are more costly and their use also brings additional pharmacological considerations. Objective: This paper investigates if the identified risk factors (renal impairment, hepatic impairment, other co-morbidities & drug interactions) influence GPs' NOAC prescribing decisions, using a multivariate probit model, while controlling for other GP characteristics. Methods: Employing primary data, collected using a dedicated survey of Irish GPs in November 2015, a multivariate probit is employed. This measures the joint decision making process of prescribing a NOAC based on four risk factors - renal impairment, hepatic impairment, other comorbidities and drug interactions. Results: Younger GPs are more likely to consider 'other co-morbidities' and 'renal impairment' as important when making NOAC prescribing decisions. Male GPs are more likely to consider 'other co-morbidities' and 'drug interactions' as important when prescribing NOACs compared to female GPs. Prescribers who have initiated NOACs are more likely to consider 'renal impairment' as important compared with non-initiators. Conclusions: Our study highlights the importance for general practitioners prescribing NOACs and caring for patients on oral anticoagulants, of adequate education, of appropriate patient selection and of appropriate monitoring of such patients. While warfarin prescribing remains predominant, NOAC prescribing is increasing. Incorporating the risk factors into prescribing decisions signals responsible prescribing for atrial fibrillation patients. Existing prescribing guidelines/toolkits need to be used in an effective manner.