What is Nuvigil? Overview of Armodafinil

Nuvigil (armodafinil) is a stimulant drug, available since June 1, 2009 in the United States, used for promoting wakefulness in adults. It is approved for excessive sleepiness during waking hours (Excessive Daytime Sleepiness, or EDS) caused by narcolepsy, sleep apnea, and shift-work sleep disorder (SWSD).

Most of what is known about armodafinil is based on modafinil, which marketed under the brand name Provigil. Cephalon owns the patents to both drugs, and currently, neither is available in generic form in the U.S. The most common side effects of Nuvigil are mild.

Armodafinil is the R-enantiomer of the racemic drug modafinil. Of the two "mirror image" versions of modafinil, R-modafinil (Nuvigil) has a longer half-life in the body. In other words, it stays in the body longer than the other "mirror image" version, S-modafinil.

Armodafinil has been proven safe and effective as a wakefulness-promoting agent. Because it has a longer half-life, it should theoretically be more effective than the same amount of modafinil, since more of the drug remains in the body. However, studies to prove this true are lacking.

The three conditions for which Nuvigil is approved in the U.S. are all sleep disorders.

Narcolepsy is a neurological condition in which the sleep cycle is triggered frequently and unexpectedly during the day. It can be very disruptive to sufferers' lives, as well as dangerous.

Obstructive sleep apnea (OSA) is a condition in which the airway is periodically blocked during sleep, causing the person to stop breathing, then wake up in order to start breathing again. Often (but not always) caused by obesity, OSA can make its sufferers very fatigued during the day due to frequent sleep interruptions.

SWSD is excessive sleepiness and/or insomnia caused by frequent interruptions to the 24-hour sleep/wake cycle, often experienced by shift workers. Both workers who work a swing or night shift for a long time, and workers who frequently change between day and night shifts, may be affected.

Off-label, both Nuvigil and its predecessor Provigil may be used for a number of conditions. These can include residual fatigue after antidepressant treatment in patients with Major Depressive Disorder, fatigue caused by the nerve disease multiple sclerosis, and the extreme fatigue associated with fibromyalgia and chronic fatigue syndrome. Physicians may treat fatigue associated with many other conditions with Nuvigil, as well. There are insufficient studies about the effectiveness of modafinil for these conditions, however. It is unknown whether armodafinil would be more effective than modafinil for these causes of fatigue.

In some studies, modafinil has been shown to be effective in both children and adults in the treatment of attention-deficit hyperactivity disorder (ADHD), with effects about equal to the commonly-used stimulants methylphenidate (Ritalin, Metadate, Concerta, and others) and amphetamines (Adderall, Dexedrine, Vyvanse, and others). It is not approved as an ADHD treatment, however, due to concerns about its safety, especially for children and adolescents.

Modafinil has also successfully treated bipolar depression, a notoriously difficult condition to treat. It should only be used in bipolar patients in whom stimulants do not trigger mania.

• FDA label for armodafinil (NUVIGIL).
• R. Kumar. "Approved and investigational uses of modafinil: an evidence-based review." Drugs. 2008;68(13):1803-39.