Managing drug-drug interactions with new direct-acting antiviral agents in chronic hepatitis C.

Several direct-acting antiviral agents (DAAs) have marketing authorization in Europe and in the USA and have changed the landscape of hepatitis C treatment: each DAA has its own metabolism and drug-drug interactions (DDIs), and managing them is a challenge. To compile the pharmacokinetics and DDI data of the new DAA and to provide a guide for management of DDI. An indexed MEDLINE search was conducted using the keywords: DAA, hepatitis C, simeprevir, daclatasvir, ledipasvir, sofosbuvir, 3D regimen (paritaprevir/ritonavir, ombitasvir, dasabuvir), DDI and pharmacokinetics. Data were also collected from hepatology, and infectious disease and clinical pharmacology conferences abstracts. Food can play a role in the absorption of DAAs. Most of the interactions are linked to metabolism (cytochrome P450-3 A4 [CYP3A4]) or hepatic and/or intestinal transporters (organic anion-transporting polypeptide and P-glycoprotein [P-gp]). To a lesser extent other pathways can be involved such as breast cancer resistance protein transporter or UDP-glucuronosyltransferase metabolism. DDI are more likely to occur with 3D regimen, daclatasvir, simeprevir and ledipasvir, as they are all both substrates and inhibitors of P-gp and/or CYP3A4, than with sofosbuvir. They can increase concentrations of coadministered drugs and their concentrations may be influenced by P-gp or CYP3A4 inducers or inhibitors. Overdosage or low dosage can be encountered with potent inducers or inhibitors of CYP3A4 or drugs with a narrow therapeutic range. The key to interpret DDI data is a good understanding of the pharmacokinetic profiles of the drugs involved. Their ability to inhibit CYP450-3A4 and transporters (hepatic and/or intestinal) can have significant clinical consequences.

Impact of medication reconciliation at discharge on continuity of patient care in France.

Background Care transitions from hospital to community have been identified as risk points for the continuity of patient care. Without upstream information, the community pharmacist (CP) cannot ensure error-free drug dispensing. A hospital-to-community records transmission process would enable CPs to guarantee that all prescription drugs are ready to pick up at hospital discharge, and to improve their responses to patient health inquiries. Objective To evaluate the impact of a hospital-to-CP medication records scheme on post-discharge continuity of patient treatment. Setting A University Hospital Digestive Surgery Department. Method Prospective, single-center, randomized pilot study. Eligible adult Digestive Surgery department patients discharged home over a period of 4 months were included. The medication reconciliation procedure was the same in both arms of the study. For patients included in the intervention group, CPs were sent the discharge prescription, patient medication list, and clinical and biological data required for drug dispensing. At 7 ± 2 days post-discharge, the CPs were surveyed by questionnaire. Seamlessness of drug continuity, use of the discharge medication form, and CP satisfaction with the scheme were assessed. Main outcome measures Prevalence of medication shortages, i.e. CPs unable to supply the appropriate drugs at discharge, and CP satisfaction levels, analyzed using Chi squared test. Results 124 patients were included. Of 124 CPs surveyed, 104 returned a completed questionnaire. Analysis found medication shortage in 10 control-group patients and one intervention-group patient (p < 0.005), non-availability of the full prescription in 24 % of control-group patients and 6 % of intervention-group patients (p < 0.013). In terms of CP satisfaction, 96 % of the intervention-group CPs stated that they were satisfied with the new hospital-to-community liaison initiative, while just 24 % of control-group CPs were satisfied with the current level of hospital-to-community liaison. Mean hospital pharmacist time input required for this initiative was an estimated 21 min for the control group versus 35 min for the intervention group. Conclusion The results provide a strong rationale for embedding the process longer-term and extending it out to other healthcare services. A pre-project study is needed to define which service departments and patients groups should be given priority for this process initiative.

Drug interactions and protease inhibitors used in the treatment of hepatitis C: how to manage?

PURPOSE: The first-generation protease inhibitors (PI) boceprevir and telaprevir combined with pegylated interferon have revolutionized the treatment of type-1 hepatitis C by increasing the rates of sustained virologic response. However, they induce drug interactions, and their clinical relevance is difficult to predict. This review compiles available data on drug-drug interactions (DDI) based on their pharmacokinetic and pharmacodynamic properties with the aim of assisting clinicians in managing DDI METHODS: PubMed, drug interaction databases and hepatology and infectious disease conference abstracts were systematically searched using the key search terms "interaction", "hepatitis C", "telaprevir" and "boceprevir". All known interactions were compiled and reclassified according to their pharmacokinetic and pharmacodynamic mechanisms. The state of knowledge of interaction mechanisms are reported and a therapeutic approach is proposed. RESULTS: Boceprevir and telaprevir are both substrates and potent inhibitors of cytochrome P450 3A4 and the drug transporter P-glycoprotein. They induce overdosage but can sometimes decrease the effect of other drugs by inducing other cytochromes. Overdosage or low dosage mainly affects drugs with a narrow therapeutic range, such as immunosuppressants or antiretrovirals. The distribution and elimination of PI are unaffected by interactions. In terms of pharmacodynamic interactions, PI can trigger drug-induced QT interval prolongation, which means that clinicians should manage such risk factors as potassium/magnesium levels or avoid other QT-prolonging drugs. CONCLUSIONS: Management of hepatitis C therapy is complex. The key to interpreting DDI data is a solid understanding of the pharmacokinetic and pharmacodynamic profiles of the drugs involved. Their ability to inhibit cytochrome P450 3A4 and prolong the QT interval can have significant clinical consequences. This review provides a practical guide to the safe and effective management of therapy with boceprevir and telaprevir.