A review on modafinil: the characteristics, function, and use in critical care

In critically ill patients, sleep is generally interrupted. Some factors that lead to such sleep interruption include the intensive care unit (ICU) circumstance, primary medical disease itself, mental stress, and impacts of many drugs and other managements utilized to treat ICU patients. Another illness that may cause profound daytime somnolence is narcolepsy. Modafinil, methylphenidate and amphetamines are used as stimulants to treat symptoms, such as extreme daytime sleepiness, cataplexy and nocturnal sleep disruption. Such stimulants can increase awareness, improve perception and thinking, as well as assist in keeping people awake. The exact mechanism of action of modafinil is unclear. In vitro studies have demonstrated that binding of modafinil to the dopamine reuptake pump can prevent the reuptake of dopamine, resulting in a boost in extracellular dopamine. Modafinil is a racemic compound containing l and d isomers. Peak plasma concentrations of the drug occur at 2–4 h after administration; therefore, the absorption of modafinil is considered fast. Modafinil is properly distributed in tissues by binding to plasma proteins moderately. Despite the likely role of modafinil in improving cognition and arousal in critically ill patients, the available data on the use of modafinil in the ICU setting is limited. The aim of the study was to review the novel usage of modafinil for alleviation of fatigue, excessive daytime somnolence (EDS), and/or depression in critically ill patients.