Ketoconazole as a Secondary Hormonal Intervention in Advanced Prostate Cancer

Advances in the Treatment of Metastatic Prostate Cancer

During the past several years, there has been substantial progress in the development of treatments for advanced prostate cancer with the approval of multiple new life-prolonging agents using different mechanisms of action. Such progress was attainable because of advances in our understanding of the biology behind mechanisms of androgen receptor pathway activation, complex tumor-microenvironment interaction of bone metastasis, antitumor immunology, and new oncogenic pathways. Continuous efforts are being made to develop new therapeutics with novel mechanisms of action, define the optimal sequences and/or combinations of current agents, and identify reliable surrogate end points to facilitate new drug development.

Non-anti-infective effects of antimicrobials and their clinical applications: a review

Antimicrobial agents are undoubtedly one of the key advances in the history of modern medicine and infectious diseases, improving the clinical outcomes of infection owing to their inhibitory effects on microbial growth. However, many antimicrobial agents also have biological activities stemming from their interactions with host receptors and effects on host inflammatory responses and other human or bacterial cellular biological pathways. These result in clinical uses of antimicrobial drugs that are distinct from their direct bacteriostatic or bactericidal properties. We reviewed the published literature regarding non-anti-infective therapeutic properties and proposed clinical applications of selected antimicrobials, specifically, macrolides, tetracyclines, sulfonamides, and ketoconazole. The clinical applications reviewed were varied, and we focused on uses that were clinically relevant (in terms of importance and burden of disease) and where published evidence exists. Such uses include chronic inflammatory pulmonary and skin disorders, chronic periodontitis, gastrointestinal dysmotility, rheumatoid arthritis, and cancer. Most of these potential therapeutic uses are not Food and Drug Administration approved. Clinicians need to weigh the use of antimicrobial agents for their non-anti-infective benefits, considering potential adverse effects and long-term effect on microbial resistance.

Enhanced Interaction between Warfarin and High-Dose Ketoconazole: A Case Report

This case describes the increased anticoagulation effect associated with the use of high-dose ketoconazole. A 59-year-old man treated with warfarin for aortic valve replacement was prescribed high-dose ketoconazole and hydrocortisone for the treatment of prostate cancer. Despite lowering the warfarin dosage by 35% during the start of high dose ketoconazole, an additional dose reduction was required subsequently when the INR rose from 2.62 to 3.82 within nine days. After a total dose reduction of 43%, the INR returned to therapeutic range within two weeks. The Naranjo probability scale revealed a probable adverse reaction of increased anticoagulant effect associated with high dose ketoconazole. Due to the inhibition of warfarin metabolism by ketoconazole, patients taking high dose ketoconazole concomitantly with warfarin may need their warfarin dosage reduced by more than is currently recommended, as well as receive more frequent INR monitoring to avoid over anticoagulation.

Ketoconazole-Evoked [Ca2+]iRises and Non-Ca2+-Triggered Cell Death in Rabbit Corneal Epithelial Cells (SIRC)

The effect of ketoconazole on cytosolic free Ca2+ concentrations ([Ca2+]i) and proliferation has not been explored in corneal cells. This study examined whether ketoconazole alters Ca2+ levels and causes cell death in SIRC rabbit corneal epithelial cells. [Ca2+]i and cell viability were measured by using the fluorescent dyes fura-2 and WST-1, respectively. Ketoconazole at concentrations of 5 microM and above increased [Ca2+]i in a concentration-dependent manner. The Ca2+ signal was reduced partly by removing extracellular Ca2+. The ketoconazole-induced Ca2+ influx was insensitive to L-type Ca2+ channel blockers and protein kinase C modulators. In Ca2+-free medium, after pretreatment with 50 microM ketoconazole, thapsigargin-(1 microM)-induced [Ca2+]i rises were abolished; conversely, thapsigargin pretreatment nearly abolished ketoconazole-induced [Ca2+]i rises. Inhibition of phospholipase C with 2 microM U73122 did not change ketoconazole-induced [Ca2+]i rises. At concentrations between 5 and 100 microM, ketoconazole killed cells in a concentration-dependent manner. The cytotoxic effect of 50 microM ketoconazole was not reversed by prechelating cytosolic Ca2+ with BAPTA. In summary, in corneal cells, ketoconazole-induced [Ca2+]i rises by causing Ca2+ release from the endoplasmic reticulum and Ca2+ influx from unknown pathways. Furthermore, the cytotoxicity induced by ketoconazole was not caused via a preceding [Ca2+]i rise.