Proton pump inhibitors (PPIs) are widely prescribed for the treatment of gastric acid-related disorders and the eradication of Helicobacter pylori. In addition, they are routinely prescribed for the prevention of gastrointestinal bleeding in patients receiving a dual antiplatelet therapy consisting of clopidogrel and aspirin (acetylsalicylic acid) after myocardial infarction or percutaneous coronary intervention and stenting. Because PPIs are given to these patients for long periods, there is a concern about the potential for clinically significant drug-drug interactions (DDIs) with concomitantly administered medications. Because PPIs give rise to profound and long-lasting elevation of intragastric pH, it is not surprising that they interfere with the absorption of concurrent medications. Drug solubility may be substantially reduced at neutral pH compared with acidic conditions. In this context, PPIs have been shown to reduce the bioavailability of many clinically relevant drugs (e.g. ketoconazole, atazanavir) by 50% or more compared with the control values. Soon after the introduction of omeprazole (a prototype PPI) into the market, it was reported that omeprazole was associated with 30% and 10% reductions in systemic clearance of diazepam and phenytoin, respectively. In vitro studies demonstrating the inhibitory effects of omeprazole on the metabolism of these drugs with human liver microsomes gave a mechanistic explanation for the DDIs. Numerous subsequent studies have been performed to investigate the DDI potential of PPIs associated with the metabolic inhibition of cytochrome P450 (CYP) enzyme activities; however, most such attempts have failed to find clinically relevant results. Nevertheless, recent large-scale clinical trials have raised concerns about possible DDIs between PPIs and an antiplatelet drug, clopidogrel. It has been suggested that coadministration of PPIs with a dual antiplatelet therapy consisting of clopidogrel and aspirin may attenuate the anti-aggregation effects of those medications and augment the risk of cardiovascular ischaemic events. There is a possibility that PPIs may elicit detrimental effects by inhibiting CYP2C19-dominated metabolism of clopidogrel to its active metabolite. Further studies are urgently required to clarify the mechanism of this DDI and to explore new aspects of the DDI potential of PPIs.

The purpose of the present review article is to update the information regarding pharmacokinetics of drugs in patients with heart failure that has accumulated since the last review article published in 1988 in Clinical Pharmacokinetics. Since this last review, our understanding of the pathophysiology of heart failure has changed from the cardio-renal model to the neuro-humoral model, and the pharmacologic approach to treatment of heart failure has been shifted from inotropic agents to those acting on the renin-angiotensin-aldosterone system. The pharmacologic agents now used for heart failure include many important classes of drugs, such as ACE inhibitors, angiotensin receptor blockers (antagonists) (ARBs), and mineralocorticoid receptor antagonists. In Part 1 of this review, we summarized the pharmacokinetic properties of relevant drugs administered intravenously. In Part 2, the present article, we describe pharmacokinetics of drugs following oral administration. For this purpose we conducted a systematic search of literature using MEDLINE, EMBASE, and Japan Centra Revuo Medicina (in Japanese). We retrieved a total of 110 relevant publications for 49 drugs and updated the information for ten drugs and provided new information for 31 drugs. We recognized that the pharmacokinetic data were obtained primarily from stable heart failure patients with moderate severity [New York Heart Association (NYHA) class II or III]. In addition, most patients were classified as heart failure with reduced ejection fraction. Furthermore, because most of the studies retrieved had no comparative groups of healthy subjects or patients without heart failure, historical controls from previous studies were used for comparisons. In Part 2, we also discuss the pharmacokinetics of active metabolites as well as parent drugs, because many drugs given by oral administration for the treatment of heart failure are prodrugs (e.g., ACE inhibitors and ARBs). The pharmacokinetic changes of drugs in patients with heart failure are discussed in the light of a physiologically based pharmacokinetic model. In addition, we discuss the effects of intestinal tissue heart failure-associated edema on drug absorption as it relates to the biopharmaceutical classification system, particularly for drugs demonstrating reduced systemic exposure as measured by the area under the plasma concentration-time curve after oral administration (AUCpo) in patients with heart failure as compared with healthy subjects. After review of the available data, it was seen that among patients with asymptomatic or compensated chronic heart failure there seemed to be no or minimal alterations in the maximum concentration (C max) and AUCpo of the included drugs, unless there was concurrent liver and/or renal dysfunction. In contrast, the AUCpo of at least 14 drugs (captopril, cilazaprilat, enalapril/enalaprilat, perindopril, carvedilol, candesartan, pilsicainide, felodipine, furosemide, enoximone, milrinone, flosequinan, molsidomine, and ibopamine) were suspected or documented to increa...

We propose that an extended loading regimen (400 mg every 12 hours for the first 5 doses) would be a treatment option to maximize the therapeutic effects of teicoplanin in patients with systemic MRSA infection.

Our findings suggest that the administration of immunosuppressive agents in patients with either CD or UC probably does not confer a significantly increased risk of malignancy compared with patients with IBD who are not receiving these agents.

Eculizumab given bi-weekly is widely recommended for the treatment of paroxysmal nocturnal hemoglobinuria (PNH). We undertook a retrospective analysis on the medical records of 763 dosings of 14 PNH patients to investigate whether a threshold would exist in dosing intervals associated with breakthrough hemolysis. We identified 12 events of breakthrough hemolysis in 4 patients. Multivariate logistic regression and receiver operating characteristics (ROC) analysis revealed a significant association between increased risk of breakthrough hemolysis and prolonged dosing intervals of 17 days or more and concomitant inflammation: odds ratios (OR) and 95% confidence intervals (CIs) were 1.6 (1.3-2.0, p<0.01) and 5.5 (1.3-22.8, p 0.02), respectively. ROC analysis showed that the best cut-off dosing interval discriminating breakthrough hemolysis was 16.5 days. We consider that eculizumab dosing intervals longer than 17 days may be associated with an increased risk for developing breakthrough hemolysis in patients with PNH.