Furosemide-probenecid interaction as a laboratory exercise for undergraduate education in clinical pharmacology

Safety and tolerability of available urate-lowering drugs: a critical review

INTRODUCTION

Urate-lowering therapy (ULT) is the cornerstone of gout management, which is a widespread chronic illness characterized by hyperuricemia, arthropathy, tophus development, and urolithiasis. Since asymptomatic increased serum urate levels are associated with a higher risk of cardiovascular, renal and metabolic disorders, a larger use of ULTs in the general population is expected in the near future.

AREAS COVERED

This review will focus on the safety and tolerability profile of the available urate-lowering drugs: xanthine oxidase inhibitors (XOIs), uricosuric agents and injectable uricases.

EXPERT OPINION

Older drugs for ULT like allopurinol are well studied and extensively described from typical adverse effects (mild skin rash) to unusual fatal reactions, while febuxostat seems to be overall well tolerated. More evidence is required to define the safety profile of topiroxostat, arhalofenate, tranilast, and sulfinpyrazone. Furthermore, there are some unanswered questions about the pharmacological interactions of probenecid and the hepatotoxicity of benzbromarone. Despite a limited use in clinical practice, combination therapy with lesinurad or verinurad and XOI is not frequently accompanied by side effects. Rasburicase and pegloticase are usually well tolerated with some specific exceptions. Before prescribing UL drugs, physicians should take into account their safety profile tailoring the treatment on the patient characteristics.

Diuretics and epilepsy: will the past and present meet?

Clinical studies from over half a century ago suggested efficacy of a variety of diuretics in focal and generalized epilepsies as well as in status epilepticus, but these findings have not been translated into modern epilepsy training or practice. Recent advances in our understanding of neuronal maturation and the pathophysiology of neonatal seizures provide fresh insight into the mechanisms by which diuretics might reduce susceptibility to seizures. In vitro and in vivo rodent studies and human epilepsy surgical cases have shown that specific diuretic agents targeting the cation-chloride cotransporters decrease neuronal synchrony and neuronal hyperexcitability. These agents are thought to convey their antiepileptic activity by either expanding the extracellular space or promoting a cellular chloride transport balance that reflects a more developmentally "mature," less excitable state. It may be time to reexamine whether diuretics could serve as adjunctive therapies in the treatment of refractory epilepsies.

[Designing a tool to describe drug interactions and adverse events for learning and clinical routine]

Pharmacists play an important role in prescription analysis. They are involved in therapeutic drug monitoring, particularly for drugs with a narrow therapeutic index, prevention and management of drug interactions, and may be called in to identify side effects and adverse events related to drug therapy. For the polymedicated patient, the medical file, the list of prescribed drugs and the history of their administration may be insufficient to adequately assign the responsibility of a given adverse effect to one or more drugs. Graphical representations can sometimes be useful to describe and clarify a sequence of events. In addition, as part of their academic course, students have many occasions to hear about "side effects" and "drug interactions". However, in the academic setting, there are few opportunities to observe the evolution and the consequences of these events. In the course of their hospital training, these students are required to perform patient follow-up for pharmacotherapeutic or educational purposes and to comment case reports to physicians. The aim of this paper is to present a tool facilitating the graphic display of drug interaction consequences and side effects. This tool can be a useful aid for causality assessment. It structures the students' training course and helps them better understand the commentaries pharmacists provide for physicians. Further development of this tool should contribute to the prevention of adverse drug events.

Favorable effect on postgraduate clinical practice of a drug-interaction exercise for undergraduate students

AIM

Undergraduate students in Jichi Medical School participated in a laboratory exercise investigating the furosemide-probenecid interaction at the end of their clinical pharmacology (CP) course. The aim of this study was to determine whether they learned to recognize drug interactions better than students who did not take such a course.

METHODS

We conducted a postal survey of physicians who had graduated from Jichi Medical School or from other medical schools without a CP course including the exercise. Questions were asked concerning: (1) the recognition of furosemide-probenecid and nine other drug interactions, and (2) the need to anticipate drug interactions and their adverse effects before writing prescriptions.

RESULTS

The degree of the recognition of all drug interactions, and the percentage of physicians who responded that knowledge of drug interactions and adverse effects were essential before writing prescriptions, were significantly greater in physicians who had taken an undergraduate CP course than in those who had not.

CONCLUSIONS

CP courses with specific laboratory exercises on drug interactions lead future physicians to recognize drug interactions and their adverse effects.

Antihypertensive therapy: special focus on drug interactions

Today, the lifetime risk of patients aged 55-65 years to receive antihypertensive drugs approaches 60%. Yet, recent trials suggest that hypertension is not adequately controlled in the majority of patients. The prevalence of hypertension increases with advancing age, as does the prevalence of comorbid conditions and the total number of medications taken. Multi-drug therapy, advancing age and comorbid conditions are also key risk factors for adverse drug reactions and drug interactions. In this review, the authors evaluate the most frequently used antihypertensive drugs (diuretics, beta-adrenergic blockers, angiotensin-converting enzyme inhibitors, calcium channel blockers, angiotensin II receptor Type 1 blockers and alpha-adrenergic blockers) with special reference to pharmacodynamic and pharmacokinetic drug interactions. As the spectrum of drugs prescribed is constantly changing, safety yesterday does not imply safety today and safety today does not imply safety tomorrow. Furthermore, therapeutic efficacy should not be neglected over concerns regarding drug interactions. Many patients are at risk of clinically relevant drug interactions involving antihypertensive drugs but, presently, even more patients may be at risk of suffering from the consequences of their inadequately treated hypertension. In this respect, the authors discuss controversial viewpoints on the overall clinical relevance of drug interactions occurring at the level of cytochrome P450 metabolism.