Anti-oxidants for therapeutic use: why are only a few drugs in clinical use?

It is well known that ROS are involved in a wide spectrum of diseases. In spite of this fact, only a few drugs are currently in use in clinical settings: Ebselen for the treatment of cerebral infarctions, N-acetylcysteine for over-doses of acetaminophen. Because ROS production is very common and the human body has an abundant capacity for producing anti-oxidants, it is difficult to obtain statistical differences in trials designed to evaluate an anti-oxidative drug. Additional resources will be needed, if we are to use anti-oxidants in human clinical settings; Drug delivery to a specific region, appropriate setting of evaluation goals in clinical trials, new approaches to understanding the details of anti-oxidative systems. In spite of these drawbacks, the additional use of anti-oxidants in clinical settings is clearly warranted, and could contribute positively to human health. It is generally thought that reactive oxygen species (ROS) are involved in a wide variety of diseases, including ischemia-reperfusion, cancer and various types of inflammation. Because of this, the therapeutic use of antioxidants is now widespread. Some of these have been shown to be successful, but many appear to have no or little benefit, in terms of being beneficial to general health or in disease prevention. In this commentary, the author takes a look back at important anti-oxidative drugs and wonders why only a few such drugs are currently in clinical use.