Modafinil, sold under the brand name Provigil among others, is a central nervous system (CNS) stimulant and eugeroic (wakefulness promoter) medication used primarily to treat narcolepsy, a sleep disorder characterized by excessive daytime sleepiness and sudden Microsleep. Modafinil is also approved for stimulating wakefulness in people with sleep apnea and shift work sleep disorder. It is taken by mouth. Modafinil is not approved by the US Food and Drug Administration (FDA) for use in people under 17 years old.
Common side effects of Modafinil include anxiety, insomnia, dizziness, and headache. Modafinil has potential for causing severe allergic reactions, Psychiatry effects, hypersensitivity, adverse effect drug interaction with prescription drugs, and misuse or drug abuse. Modafinil may harm the fetus if taken during or two months prior to pregnancy.
While modafinil is used as a Nootropic, or "smart drug", among healthy individuals seeking improved focus and productivity, its use outside medical supervision raises concerns regarding potential misuse or abuse. Research on the cognitive enhancement effects of modafinil in non-sleep deprived individuals has yielded mixed results, with some studies suggesting modest improvements in attention and executive functions, while others show no significant benefits or even a decline in cognitive functions at high doses.
Narcolepsy causes a strong urge to sleep during the day and can include symptoms like cataplexy (sudden muscle weakness), sleep paralysis (inability to move or speak while falling asleep or waking up), and . Narcolepsy is linked to a lack of the brain chemical hypocretin (orexin), primarily produced in the hypothalamus. Modafinil is not a cure for narcolepsy, but it can help manage the symptoms. While modafinil is primarily used to treat excessive sleepiness, it may also help reduce the frequency and severity of cataplexy attacks in some people. Modafinil is approved for management of narcolepsy with or without cataplexy. However, it is not specifically approved for the treatment of cataplexy.
Modafinil is also prescribed for shift work sleep disorder.
Modafinil performs moderately (but better than armodafinil or solriamfetol) as a drug to overcome excessive daytime sleepiness caused by obstructive sleep apnea, though it is recommended that people with apnea use continuous positive airway pressure (CPAP) therapy, that is a sleep breathing apparatus to prevent apnea, before starting modafinil. When obstructive sleep apnea is comorbid with narcolepsy, modafinil is an effective drug to reduce the associated excessive daytime sleepiness.
Modafinil's use varies by region. In the US, it is approved for adult narcolepsy, shift work sleep disorder, and obstructive sleep apnea, but not for children. In the UK and the EU, since 2014, it is approved solely for narcolepsy, including in children (pediatric narcolepsy), with its use for other conditions restricted by the European Medicines Agency.
both the French and the American Academy of Sleep Medicine strongly recommend modafinil as the first-choice treatment for narcolepsy. In Europe, modafinil is considered one of the primary drugs recommended for treating narcolepsy according to the guidelines.
MS-related fatigue is a common and often debilitating symptom experienced by people with multiple sclerosis. It can significantly impact their daily functioning, quality of life, and ability to perform everyday activities. When prescribed for MS-related fatigue management, modafinil works by promoting wakefulness and increasing alertness without causing drowsiness or disrupting nighttime sleep. People with multiple sclerosis often report increased energy levels, reduced feelings of tiredness, improved cognitive function, and an overall improvement in their quality of life when taking modafinil. While modafinil can provide relief from MS-related fatigue symptoms, it does not treat the underlying cause or cure MS itself.
Given its approved status in the US to treat narcolepsy, physicians can also prescribe modafinil for off-label uses, such as treating ADHD in both children and adults.
The Canadian Network for Mood and Anxiety Treatments (CANMAT) suggests modafinil as a second-line treament for comorbid ADHD and bipolar disorder, after first-line psychostimulants and the antidepressant bupropion.
Whereas modafinil and armodafinil are approved for narcolepsy, they have been repurposed as adjunct therapy to alleviate symptoms of acute depressive phase in people with bipolar disorder. Drug repurposing in psychiatry is a strategy for discovering new uses for drugs that have already been approved or tested in clinical trials for other illnesses. As such, drug repurposing is a rapid, cost-effective, and reduced-risk strategy for the development of new treatment options for psychiatric disorders. 2021 meta-analysis concluded that add-on modafinil and armodafinil were more effective than placebo on response to treatment, clinical remission, and reduction in depressive symptoms, with only minor side effects, but the effect sizes are small and the quality of evidence is therefore low, limiting the clinical relevance of the evidence. Very low rates of mood swing (a change in mood from one extreme to another) have been observed with modafinil and armodafinil in depressive phase of bipolar disorder.
Armed forces in various countries, including the United States, the United Kingdom, India, and France, have considered modafinil as an alternative to traditional amphetamines for managing sleep deprivation in combat or extended missions. The US military approved modafinil for specific Air Force missions, replacing Amphetamine for fatigue management. The use of modafinil in military contexts without sleep deprivation is not recommended due to inconclusive evidence on its cognitive enhancement benefits and potential risks of adverse effects.
Modafinil is also available to astronauts aboard the International Space Station for the management of fatigue caused by circadian dyssynchrony in orbit.
The effectiveness of modafinil as a cognitive enhancer is still debated. Some studies suggest significant increases in cognitive abilities, while others indicate mild to nonexistent cognitive improvements. In some cases, it has even been associated with impairments in certain cognitive functions. It has been shown that modafinil's positive impact on cognitive abilities is more noticeable on sleep-deprived individuals. Therefore, in people who are not sleep-deprived, the potential of modafinil as a cognitive enhancer may be limited.
No significant changes in body weight have been observed in clinical trials, although decreased appetite and weight loss have been noted in children and adolescents. Modafinil can cause a slight increase in Transaminase, indicative of liver function, but there is no evidence of serious liver damage when levels are within reference ranges.
Rare but serious adverse effects include severe skin rashes and allergy-related symptoms. Between December 1998 and January 2007, the FDA received reports of six cases of severe cutaneous adverse reactions, including erythema multiforme, Stevens–Johnson syndrome, toxic epidermal necrolysis, and DRESS syndrome. The FDA has issued alerts regarding these risks and also noted reports of angioedema and multi-organ hypersensitivity reactions in postmarketing surveillance. In 2007, the FDA required Cephalon to modify the Provigil leaflet to include warnings about these serious conditions. The long-term safety and effectiveness of modafinil have not been conclusively established.
The FDA does not endorse modafinil for children's medical conditions due to an increased risk of rare but serious dermatological toxicity, manifested as Stevens–Johnson syndrome which is a type of severe skin reaction. However, in Europe, modafinil may be prescribed for treating narcolepsy in children.
Modafinil is contraindicated for individuals with known hypersensitivity to either modafinil or armodafinil.
Modafinil is also contraindicated in certain cardiac conditions, including uncontrolled moderate to severe hypertension, arrhythmia, cor pulmonale, and in cases with signs of CNS stimulant-induced mitral valve prolapse or left ventricular hypertrophy. The package insert in the United States cautions about using modafinil in people with a documented medical history of left ventricular hypertrophy or those diagnosed with mitral valve prolapse who have previously exhibited symptoms associated with the mitral valve prolapse syndrome while undergoing treatment involving central nervous system stimulants. The reasons why modafinil is contraindicated in certain cardiac conditions are because modafinil affects the autonomic nervous system and, in particular, exerts significant effects on autonomic cardiovascular regulation, leading in some people to notable increases in heart rate and blood pressure. These substantial changes in the autonomic system warrant careful consideration when prescribing modafinil to people with pre-existing cardiovascular conditions. The increase in heart rate and blood pressure can worsen the symptoms of such pre-existing conditions as hypertension, arrhythmia, and cor pulmonale. These changes in the autonomic system induced by modafinil can increase the risk of heart attack, stroke, and heart failure. Modafinil can stimulate the release of norepinephrine and epinephrine, hormones that activate the sympathetic nervous system. This can cause vasoconstriction, which is the narrowing of blood vessels, and increase the heart's workload, which is not desired in people with pre-existing heart conditions. In particular, modafinil can worsen the consequences of mitral valve prolapse or left ventricular hypertrophy, which are structural abnormalities of the heart. These can affect the blood flow and oxygen delivery to the heart and other organs.
Modafinil is also contraindicated in people with congenital problems like galactose intolerance, lactase deficiency, or glucose-galactose malabsorption.
While modafinil is generally found to be safe and significant adverse effects are rare, including in pediatric narcolepsy cases (sleep disorders in children), there is evidence that long-term usage can lead to tolerance in some individuals. This necessitates higher doses to maintain the same level of cognitive enhancement or relief from sleepiness.
People with current or past substance addictions and those with a family history of addiction are particularly at risk for developing tolerance.
The mechanisms driving tolerance to modafinil, which may involve its impact on dopamine and norepinephrine levels in the brain, are not fully understood.
Repeated administration of modafinil for off-label use, such as increased alertness and cognitive-enhancing effects in sleep deprivation, can lead to drug tolerance, which means that the effectiveness of the drug may decrease over time. Still, modafinil therapy as a eugeroic agent to treat narcolepsy does not typically lead to drug tolerance, i.e., the effectiveness does not usually decrease on prolonged use, although individual responses may vary.
Modafinil was not observed to promote overuse or misuse, even in people who have a history of cocaine addiction. Despite the initial belief that modafinil carried no abuse potential, emerging evidence suggests that it works at the same neurobiological mechanisms as other addictive stimulants. Consequently, there exists a potential risk of modafinil abuse, necessitating prudent consideration and caution when prescribing or using this medication. Modafinil exhibits a lower response on the amphetamine scale of the addiction research center inventory, suggesting reduced propensity for abuse compared to amphetamine.
The US Drug Enforcement Administration has classified modafinil as a Schedule IV controlled substance; the medicine is recognized for having valid medical uses with low addiction potential. The International Narcotics Control Board does not classify it as a narcotic or a psychotropic substance.
Allergic reactions such as rash, angioedema, anaphylaxis, and Stevens–Johnson syndrome may rarely be triggered by an immunological response to modafinil or its metabolites. Cardiovascular complications like hypertension, tachycardia, chest pain, and may also be observed due to modafinil's sympathomimetic action.
In animal studies, the median lethal dose (LD50) of modafinil varies among species and depends on the route of administration. In mice and rats, the LD50 is approximately if administered via an injection, but the oral LD50 for rats is . The LD50 value for humans have not been established. Human clinical trials have involved total daily doses up to for 7–21 days. Acute one-time total overdoses up to have not been life-threatening but resulted in symptoms like agitation, insomnia, tremor, palpitations, and gastrointestinal disturbances.
The management of modafinil overdose involves supportive care, monitoring of vital signs, and treatment of specific complications. In cases of recent consumption, activated charcoal, gastric lavage, or hemodialysis may be used. There is no specific antidote for modafinil overdose. The main way to deal with modafinil overdose is supportive care, which includes sedating the patient and stabilizing their blood pressure, and muscle activity in case of manifestations such as agitation or tremor.
Modafinil is a weak to moderate enzyme inducer of CYP3A4 and a weak inhibitor of CYP2C19, enzymes of the cytochrome P450 group of enzymes. Modafinil also induces or inhibits other cytochrome P450 enzymes. One in vitro study predicts that modafinil may enzyme inducer the cytochrome P450 enzymes CYP1A2, CYP3A4, and CYP2B6, as well as may inhibit CYP2C9 and CYP2C19. However, other in-vitro studies find no significant inhibition of CYP2C9. Modafinil may induce P-glycoprotein, which may affect drugs transported by P-glycoprotein, such as digoxin.
It was clinically found that modafinil affects pharmacodynamics of drugs which are metabolized by CYP3A4 and other enzymes of the cytochrome P450 family so that interactions of modafinil with these drugs were observed in real people, rather than being predicted in a lab setting. For instance, it was observed that induction of CYP3A4 by modafinil affects metabolism of the following and endogenous substances:
Hypertensive crises have been reported when armodafinil (one of modafinil's ) has been taken with monoamine oxidase inhibitors (MAOIs) like tranylcypromine.
The precise mechanism of action of modafinil for narcolepsy and other sleep disorders remains unclear.
From laboratory research, modafinil has little to no affinity for serotonin or norepinephrine transporters and does not directly interact with these systems. However, studies have shown that elevated concentrations of norepinephrine and serotonin can occur as an indirect effect following modafinil administration due to increased extracellular dopamine activity. Unlike traditional psychostimulant drugs, such as cocaine or amphetamine, modafinil shows low potential for causing euphoria due to differences in how it interacts with dopamine transporters at a cellular level.
In addition to its influence on dopaminergic pathways, modafinil may impact other neurotransmitter systems, such as orexin (hypocretin). Orexin neurons are involved in promoting wakefulness and regulating arousal states. Modafinil may increase signaling within hypothalamic orexin pathways, potentially contributing to its wake-promoting effects.
Renal excretion of unchanged modafinil usually accounts for less than 10% of an oral dose. This means that when modafinil is taken by mouth, the only approved route of administration, less than 10% of the drug is eliminated from the body through the urine without being metabolized by the liver or other organs. The rest of the drug is either metabolized or excreted through other routes, such as feces or bile.
The two major circulating of modafinil are modafinil acid (CRL-40467) and modafinil sulfone (CRL-41056). Both of these metabolites have been described as inactive, and neither appears to contribute to the wakefulness-promoting effects of modafinil. However, modafinil sulfone does appear to possess anticonvulsant effects, a property that it shares with modafinil.
Elimination half-life is in the range of 10 to 12 hours, subject to differences in sex, in cytochrome P450 , liver function and renal function. Modafinil is metabolized mainly in the liver, and its inactive metabolites are excreted in the urine. Urinary excretion of the unchanged drug is usually less than 10% but can range from 0% to as high as 18.7%, depending on the factors mentioned.
Modafinil exhibits sex-specific pharmacokinetic differences. It demonstrates higher bioavailability in women compared to men. The mean Cmax is higher in women than in men, vs. (p < 0.05), following a single oral dose of modafinil. This difference persists even after adjusting for body weight ( vs. ). The clearance of modafinil is 30% higher in men than in women, and plasma concentrations after a single dose are significantly higher in women than in men. These sex-specific pharmacokinetic differences may have implications for the efficacy and safety of modafinil.
Modafinil is a racemic mixture of two , armodafinil (( R)-modafinil) and esmodafinil (( S)-modafinil).
Reagent testing can screen for the presence of modafinil in samples.
The FDA approved modafinil in 1998 for narcolepsy treatment, and later for shift work sleep disorder and obstructive sleep apnea in 2003. It was approved in the UK in December 2002. In the United States, modafinil is marketed by Cephalon, who acquired the rights from Lafon and purchased the company in 2001.
Cephalon introduced armodafinil, the ( R)-enantiomer of modafinil, in the United States in 2007. Generic versions of modafinil became available in the US in 2012 after extensive patent litigation.
Finland
In Finland, modafinil is a prescription drug but not listed as a controlled substance. Finland is a member of the European Union, and it is illegal to import prescription medicine from outside the European Union unless the person has a valid prescription.
It is illegal to import modafinil to the United States without a Drug Enforcement Administration (DEA)–registered importer and a prescription. Individuals may legally bring modafinil into the US from a foreign country for personal use, limited to 50 dosage units, with a prescription and proper declaration at the border. Under the Pure Food and Drug Act, marketing drugs for off-label uses is prohibited. Cephalon, the manufacturer of Provigil, faced legal issues for promoting off-label uses and paid significant fines in 2008.
Concerns have been raised about the growing use of modafinil as a "smart drug" or cognitive enhancer among healthy individuals who use it with the aim to improve concentration and memory. In 2003, modafinil sales were skyrocketing, with some experts concerned that it had become a tempting pick-me-up for people looking for an extra edge in a productivity-obsessed society. The cost of modafinil varied depending on factors such as location and insurance coverage; still, in 2004, the price of modafinil in the US was around $120 or more per monthly supply. However, the availability of generic versions has increased since then and may have driven down prices.
In 2020, modafinil was the 302nd most commonly prescribed medication in the United States, with just over 1,000,000 prescriptions.
Following the nearing expiration of marketing rights in 2002, generic manufacturers, including Mylan and Teva, applied for FDA approval to market a generic form of modafinil, leading to legal challenges by Cephalon regarding the particle size patent. The patent RE 37,516 was declared invalid and unenforceable in 2011.
In addition, Cephalon entered agreements with several generic drug manufacturers to delay the sale of generic modafinil in the US. These agreements were subject to legal scrutiny and antitrust investigations, culminating in a ruling by the Court of Appeals in 2016, which found that the settlements did not violate antitrust laws.
Several athletes, such as sprinter Kelli White in 2003, cyclist David Clinger and basketball player Diana Taurasi in 2010, and rower Timothy Grant in 2015, were accused of using modafinil as a performance-enhancing doping agent. Taurasi and another player—Monique Coker, tested at the same lab—were later cleared. Kelli White, who tested positive after her 100m victory at the 2003 World Championships in Paris, was stripped of her gold medals. She claimed that she used modafinil to treat narcolepsy, but the International Association of Athletics Federations (IAAF) ruled that modafinil was a performance-enhancing drug.
The BALCO scandal brought to light an unsubstantiated (but widely published) account of Major League Baseball's all-time leading home-run hitter Barry Bonds' supplemental chemical regimen that included modafinil in addition to and human growth hormone.
However, evidence of modafinil for treatment of adult ADHD is mixed, and a 2016 systematic review of alternative drug therapies for adult ADHD did not recommend its use in this context. In a later large phase 3 clinical trial of modafinil for adult ADHD, modafinil was not effective in improving symptoms, there was also a high rate of side effects (86%) and discontinuation (47%). The poor tolerability of modafinil in this study was possibly due to the use of high doses (). Another reason for the denial of the approval was due to concerns about rare but serious dermatological toxicity in Stevens–Johnson syndrome.
The research on the use of modafinil for treating individuals with Autism Spectrum Disorder (ASD) who also exhibit ADHD symptoms is currently in its early stages with no results delivered.
A 2020 review reported that modafinil has a modest effect on memory updating, but the effect is small and may not accurately reflect the perception that it is useful as a cognitive enhancer, as there is insufficient evidence to support such a claim.
Disorders of consciousness are states characterized by impaired arousal and awareness. These states include coma, vegetative state/unresponsive wakefulness syndrome (VS/UWS), minimally conscious state (MCS), cognitive motor dissociation, and covert cortical processing. Brain injuries can impair consciousness through neuroanatomic lesions involving the bilateral cerebral hemispheres, rostral brainstem, diencephalon, or basal forebrain.
Neuroimaging studies have shown that modafinil increases cerebral blood flow in several brain regions, such as the thalamus, locus coeruleus, limbic system, and insular cortex; still, observational reports on the use of modafinil in patients with disorders of consciousness have produced mixed results, indicating that its effectiveness may vary among individuals.
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+ Modafinil activity profile Footnotes: a = Functional activity, not binding inhibition. b = Armodafinil at D2High. Notes: No activity at a variety of other assessed targets.
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+ Colors produced by modafinil with various reagents Deep orange/red
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the global sales figures for modafinil are not known. Still, modafinil sold under the brand name Provigil accounted for over 40% of [[Cephalon]]'s global turnover for several years, according to the information published in 2020.
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