Modafinil

Due to modafinil's lack of euphoric effects, it is not considered to be a classical psychostimulant, but rather is classified as a eugeroic (wakefulness-promoting drug).[3]

Modafinil is used primarily for treatment of narcolepsy, shift work sleep disorder, and excessive daytime sleepiness associated with obstructive sleep apnea.[10][15][20][21] For obstructive sleep apnea, it is recommended that patients use continuous positive airway pressure (CPAP) appropriately before they consider starting modafinil to help with daytime sleepiness.[3] Because of the risk for development of skin or hypersensitivity reactions and serious adverse psychiatric reactions, the European Medicines Agency recommended that new patient prescriptions should be only to treat sleepiness associated with narcolepsy.[22]

The UK National Institute for Health and Care Excellence (NICE) and MS NGOs suggest modafinil to help with multiple sclerosis (MS) fatigue[23][24][25] off-label,[11] but the results from two controlled studies is conflicting, given the lack of although larger, long-term, randomized controlled studies.[26]

Modafinil is sometimes prescribed off-label to people with attention deficit hyperactivity disorder (ADHD).[27][28][29] However, there is a lack of research into modafinil for ADHD and consequently evidence supporting its use in adult ADHD compared to other treatments such as lisdexamfetamine.[30][31]

Modafinil was fielded to military personnel in the French Air Force, Foreign Legion, and Marine infantry during the Gulf War. Being more efficient than its parent drug adrafinil, it was deemed combat-worthy by the French Ministry of Defense in 1989 and subsequently administered to personnel by their officers under the name Virgyl, in order to improve a unit's "operational tempo", i.e. the rate at which military operations or activities are conducted, therefore, to enhance the unit's overall performance and efficiency. This evaluation took place before the introduction of modafinil as medication, and the personnel involved were not informed of the product's nature.[32] Later studies did not confirm the benefit of modafinil in military context that do not involve sleep deprivation.[33]

Since then, armed forces of several countries including the United States, the United Kingdom, India, and France, have expressed interest in modafinil as an alternative to amphetamine—the drug traditionally employed in combat situations or lengthy missions in which troops face sleep deprivation. The French government indicated that the Foreign Legion used modafinil during certain covert operations.[34] The United Kingdom's Ministry of Defence commissioned research into modafinil[35] from QinetiQ and spent £300,000 on one investigation.[36] In 2011, the Indian Air Force announced that modafinil was included in contingency plans.[37]

In the United States military, modafinil has been approved for use on certain Air Force missions, and it is being investigated for other military uses.[38] As of November 2012, modafinil is the only drug approved by the Air Force as a "go pill" for fatigue management (replacing prior use of amphetamine-based medications such as dextroamphetamine).[39]

The Canadian Medical Association Journal reports that modafinil is used by astronauts on long-term missions aboard the International Space Station. Modafinil is "available to crew to optimize performance while fatigued" and helps with the disruptions in circadian rhythms and with the reduced quality of sleep astronauts experience.[40]

The use of modafinil in military contexts that do not involve sleep deprivation is not recommended due to limited evidence on its effectiveness as a cognitive enhancer for non-sleep deprived individuals. Additionally, there are potential risks of abuse, overconfidence, and negative impact on physical performance associated with modafinil use outside the context of sleep deprivation.[33]

Modafinil has been used non-medically as a "smart drug" by students, office workers, transhumanists,[41][42][43][44][45] professionals in the corporate and tech fields, surgeons, truck drivers, and call-center workers. Its attention-promoting, cognitive-enhancing, and wakefulness-boosting properties are cited by those people as reasons behind modafinil's use.[46][47] However, multiple studies have consistently shown that modafinil does not provide cognitive enhancement or attention improvement benefits in non-sleep-deprived individuals, with some studies even reporting impairments in certain cognitive functions.[48]

The addiction and dependence liabilities of modafinil are very low.[1][65] Modafinil shares biochemical mechanisms with addictive stimulant drugs, and some studies reported it to have similar mood-elevating properties, although to a lesser degree.[65] It is not clear whether these effects are different from those from caffeine.[66][67] Modafinil does not appear to produce euphoric effects nor deviations (i.e. abuse) from dosages assigned to the patient,[68] however, caution should be taken, because in clinical trials modafinil produced euphoric and psychoactive effects, altering thinking, mood, feelings, and perception like other CNS stimulants,[11] so the risk of potential abuse still has to be assessed,[11] the risk of potential abuse, as there are indications that modafinil may work on the same neurobiological mechanisms as other addictive stimulants.[33]

Modafinil is classified by the United States Drug Enforcement Administration as a schedule IV controlled substance,[6] a category for drugs with valid medical uses and low addiction potential.[1][69] The International Narcotics Control Board does not consider modafinil a narcotic[70] nor a psychotropic substance.[71] Modafinil may increase abstinence rates in a subgroup of cocaine addicts, and modafinil-related discontinuation adverse effects are no different from placebo.[72]

As of 2020,[88] the precise therapeutic mechanism of action of modafinil for narcolepsy and sleep-wake disorders remains unknown,[89][90] however, the effect seems to be caused by binding of modafinil to the dopamine transporter and inhibiting dopamine reuptake.[88] Modafinil acts as an atypical, selective, and weak dopamine reuptake inhibitor and indirectly activates the release of orexin neuropeptides and histamine from the lateral hypothalamus and tuberomammillary nucleus, all of which may contribute to heightened arousal.[89][90][91][92]

Modafinil elevates dopamine levels in the hypothalamus in animals.[93] The locus of the monoamine action of modafinil was also studied, with effects identified on dopamine in the striatum and, in particular, nucleus accumbens,[94][95] norepinephrine in the hypothalamus and ventrolateral preoptic nucleus,[96][97] and serotonin in the amygdala and frontal cortex.[98] Modafinil was screened at a large panel of receptors and transporters in an attempt to elucidate its pharmacology.[83] Of the sites tested, it was observed to significantly affect only the dopamine transporter (DAT), acting as a dopamine reuptake inhibitor (DRI) with an IC₅₀ value of 4 μM.[83] Modafinil binds to the same site on the DAT as cocaine, but in a different manner.[99][100] Modafinil increases locomotor activity and extracellular dopamine concentrations in animals in a manner similar to the selective DRI vanoxerine (GBR-12909),[101] and also inhibits methamphetamine-induced dopamine release (a common property of DRIs, since DAT transport facilitates methamphetamine's access to its intracellular targets). As such, "modafinil is an exceptionally weak, but apparently very selective, [DAT] inhibitor".[102] In addition to animal research, a human positron emission tomography (PET) imaging study observed that 200 mg and 300 mg doses of modafinil resulted in DAT occupancy of 51.4% and 56.9%, respectively, which is "close to that of methylphenidate".[103] Another human PET imaging study similarly observed that modafinil occupied the DAT and also determined that it significantly elevated extracellular levels of dopamine in the brain, including in the nucleus accumbens.[104]

Modafinil has been described as an "atypical" DAT inhibitor, and shows a profile of effects that is very different from those of other dopaminergic stimulants.[105][106] For instance, modafinil produces wakefulness reportedly without the need for compensatory sleep, and shows relatively low, if any, potential for abuse.[107][102][105][106] Aside from modafinil, other atypical DAT inhibitors include vanoxerine and benztropine, which have a relatively low abuse potential similar to modafinil.[105] These drugs appear to interact with the DAT in a distinct way from "conventional" DAT blockers such as cocaine and methylphenidate.[100][105] Analogues of modafinil with modafinil-like versus cocaine-like dopamine reuptake inhibition and effects have been synthesized.[108]

Evidence against the hypothesis that modafinil exerts its effects by acting as a DRI is that tyrosine hydroxylase inhibitors (which deplete dopamine) fail to block the effects of modafinil in animals.[109] Modafinil fails to reverse reserpine-induced akinesia, whereas dextroamphetamine, a dopamine releasing agent (DRA), is able to do so.[110] One of the first published structure–activity relationship studies of modafinil found that DAT inhibition did not correlate with wakefulness-promoting effects in animals among modafinil analogues.[111] A variety of analogues without significant DAT inhibition still produce wakefulness-promoting effects.[111] "[The] neurochemical effects [of modafinil] and anatomical pattern of brain area activation differ from typical psychostimulants and are consistent with its beneficial effects on cognitive performance processes such as attention, learning, and memory".[107] Another study found that modafinil-induced increased locomotor activity in animals was dependent on histamine release and could be abolished by depletion of neuronal histamine, whereas those of methylphenidate were not and could not be.[93] Taken together, although it is established that modafinil is a clinically significant DRI, its full pharmacology remains unclear, and may include DAT-independent actions.[99][107] One such action may be activation of the orexin system.[92][99][107]

There is nonetheless evidence that modafinil produces at least some of its wakefulness-promoting effects by acting as a DRI, or at least via activation of the dopaminergic system. In support of the hypothesis that modafinil acts as a dopaminergic agent, its wakefulness-promoting effects are abolished in DAT knockout mice (although DAT knockout mice show D₁ and D₂ receptor and norepinephrine compensatory abnormalities that might confound this finding), reduced by both D₁ and D₂ receptor antagonists (although conflicting reports exist),[110] and completely blocked by simultaneous inactivation of both D₁ and D₂ receptors.[102] Modafinil shows full stimulus generalization to other DAT inhibitors including cocaine, methylphenidate, and vanoxerine, and discrimination is blocked by administration of both ecopipam (SCH-39166), a D₁ receptor antagonist, and haloperidol, a D₂ receptor antagonist.[106] Partial substitution was seen with the DRA dextroamphetamine and the D₂ receptor agonist PNU-91356A, as well as with nicotine (which indirectly elevates dopamine levels through activation of nicotinic acetylcholine receptors).[106]

Modafinil may have an additional mechanism of action: Both modafinil and its metabolite, modafinil sulfone, possess anticonvulsant properties in animals, and modafinil sulfone is nearly as potent as modafinil in producing this effect.[112] However, modafinil sulfone lacks wakefulness-promoting effects in animals, indicating that a distinct mechanism may be at play in the anticonvulsant effects of both compounds.[112]

Armodafinil, the (R)-enantiomer of modafinil, acts as a D₂^High receptor partial agonist,[113] with a K_i of 16 nM, an intrinsic activity of 48%, and an EC₅₀ of 120 nM, in rat striatal tissue.[87] Esmodafinil, the (S)-enantiomer of modafinil, is inactive with respect to the D₂ receptor.[87] Modafinil directly inhibits the firing of midbrain dopaminergic neurons in the ventral tegmental area and substantia nigra of rats via activation of D₂ receptors.[114] However, modafinil seems not to interact with the human D₂ receptor (K_i = >10 μM).[83]

There is some mouse and human evidence (via direct fMRI observation and anxiety questionnaires) to suggest that modafinil may reduce amygdala activity.[115][116] The amygdala is involved in fear processing, and the dampening of its activity reduces perceptions of fear in response to environmental stress.[117] One study documented a statistically significant reduction in fear response among human subjects given 100 mg of modafinil daily for 7 days.[115] However, another study investigating the acute effects of modafinil on fear processing reported an increase in amygdala responses to fearful faces after administration of 600 mg of modafinil in human subjects.[118] Modafinil's dose dependent effects on fear processing may exhibit a Yerkes–Dodson relationship.

C_max (peak levels) occurs approximately 2 to 3 hours after modafanil administration. Food slows absorption of modafanil, but does not affect the total AUC. In vitro measurements indicate that 60% of modafinil is bound to plasma proteins at clinical concentrations of the drug. This percentage changes very little when the concentration of modafinil is varied.[119]

Renal excretion of unchanged modafinil accounts for less than 10% of an oral dose.[7] The two major circulating metabolites of modafinil are modafinil acid (CRL-40467) and modafinil sulfone (CRL-41056).[120][7] Both of these metabolites have been described as inactive,[121] and neither appear to contribute to the wakefulness-promoting effects of modafinil.[120][7][122] However, modafinil sulfone does appear to possess anticonvulsant effects, a property that it shares with modafinil.[112]

Elimination half-life is in the range of 10 to 12 hours, subject to differences in CYP genotypes, liver function, and renal function. Modafinil is metabolized in the liver, and its inactive metabolite is excreted in the urine. Urinary excretion of the unchanged drug ranges from 0% to as high as 18.7%, depending on various factors.[119]

Armodafinil ((R)-(−)-modafinil)

Esmodafinil ((S)-(+)-modafinil)

Modafinil is a racemic mixture of two enantiomers, armodafinil ((R)-modafinil) and esmodafinil ((S)-modafinil).[86][123]

Modafinil and/or its major metabolite, modafinil acid, may be quantified in plasma, serum, or urine to monitor dosage in those receiving the drug therapeutically, to confirm a diagnosis of poisoning in hospitalized patients, or to assist in the forensic investigation of a vehicular traffic violation. Instrumental techniques involving gas or liquid chromatography are usually employed for these purposes.[124][125] As of 2011, modafinil is not tested for by common drug screens (except for anti-doping screens) and is unlikely to cause false positives for other chemically unrelated drugs such as substituted amphetamines.[86]

Reagent testing can screen for the presence of modafinil in samples.

Many derivatives and structural analogues of modafinil have been synthesized and studied.[108][128][100] Examples include adrafinil, CE-123, fladrafinil (CRL-40941; fluorafinil), flmodafinil (CRL-40940; bisfluoromodafinil, lauflumide), and modafinil sulfone (CRL-41056).[129]

U.S. Patent 4,927,855 was issued to Laboratoire L. Lafon on May 22, 1990, covering the chemical compound modafinil. After receiving an interim term extension of 1066 days and pediatric exclusivity of six months, the patent expired on October 22, 2010.

On October 6, 1994, Cephalon filed an additional patent, covering modafinil in the form of particles of defined size. That patent, U.S. Patent 5,618,845 was issued on April 8, 1997. It was reissued in 2002 as RE 37,516, which surrendered the 5618845 patent. With pediatric exclusivity, this patent expired on April 6, 2015.[133][134]

On December 24, 2002, anticipating the expiration of exclusive marketing rights, generic drug manufacturers Mylan, Teva, Barr, and Ranbaxy applied to the FDA to market a generic form of modafinil.[135] At least one withdrew its application after early opposition by Cephalon based on the RE 37,516 patent. There is uncertainty about whether a particle size patent is sufficient protection against the manufacture of generics: including whether modafinil may be modified or manufactured to avoid the granularities specified in the new Cephalon patent, and whether patenting particle size is invalid because particles of appropriate sizes are likely to be obvious to practitioners skilled in the art. However, under United States patent law, a patent is entitled to a legal presumption of validity, meaning that in order to invalidate the patent, much more than "pertinent questions" of this sort are required.

On October 31, 2011, U.S. Reissue Patent No. RE 37,516 was declared invalid and unenforceable.[136] The District Court for the Eastern District of Pennsylvania ruled that RE 37,516 was invalid because it: (1) was on sale more than one year prior to the date of the application in violation of 35 U.S.C. section 102(b); (2) was actually invented by someone else (the French company Laboratoire L. Lafon); (3) was obvious at the time the invention was made to a person having ordinary skill in the art under 35 U.S.C. section 103(a); and (4) failed the written description requirement of 35 U.S.C. section 112.[137] The patent was also found to be unenforceable due to Cephalon's inequitable conduct during patent prosecution.[137]

Cephalon made an agreement with four major generics manufacturers Teva, Barr Pharmaceuticals, Ranbaxy Laboratories, and Watson Pharmaceuticals between 2005 and 2006 to delay sales of generic modafinil in the US until April 2012 by these companies in exchange for upfront and royalty payments.[138] Litigation arising from these agreements is still pending, including an FTC suit filed in April 2008.[139]

Apotex received regulatory approval in Canada despite a suit from Cephalon's marketing partner in Canada, Shire Pharmaceuticals.[140][141] Cephalon sued Apotex in the US to prevent it from releasing a genericized armodafinil (Nuvigil).[142] Cephalon's 2011 attempt to merge with Teva was approved by the FTC under a number of conditions, including granting generic US rights to another company;[143] ultimately, Par Pharmaceutical acquired the US modafinil rights as well as some others.[144]

In the United Kingdom, Mylan Inc. received regulatory approval to sell generic modafinil produced by Orchid in January 2010; Cephalon sued to prevent sale, but lost the patent trial.[145]

Modafinil is sold under a variety of brand names worldwide, including Alertec, Alertex, Altasomil, Aspendos, Bravamax, Forcilin, Intensit, Mentix, Modafinil, Modafinilo, Modalert, Modanil, Modasomil, Modvigil, Modiodal, Modiwake, Movigil, Provigil, Resotyl, Stavigile, Vigia, Vigicer, Vigil, Vigimax, Waklert, and Zalux.[146]

In Australia, modafinil is considered to be a Schedule 4 prescription-only medicine or prescription animal remedy.[147] Schedule 4 is defined as "Substances, the use or supply of which should be by or on the order of persons permitted by State or Territory legislation to prescribe and should be available from a pharmacist on prescription."

In Canada, modafinil is not listed in the Controlled Drugs and Substances Act, but it is a Schedule F prescription drug,[148] so it is subject to seizure by Canada Border Services Agency.

In mainland China, modafinil is strictly controlled like other stimulants such as amphetamines and methylphenidate. It is classified as Class I psychotropic drug,[149] meaning that only doctors who have the right to prescribe narcotics and Class I psychotropic drugs (usually through special examination) can prescribe it, for no more than three-day use (or seven-day use for control/extend-release products).[150] The first and only modafinil product was approved in November 2017.[151]

In The Republic of Moldova, modafinil is considered a psychotropic drug[152] but can be purchased with prescription, however, importing modafinil may be considered illegal psychotropic drug (narcotics) trafficking and can be punished by up to 8 years in prison, as warned by the Customs service of Moldova.[153] In order to determine the punishment, the quantities of up to 0,002g of modafinil are considered "small quantities", while quantities in the range of 0,002g to 1,0g are considered "large quantities".[152] In Transnistria, modafinil is a prohibited substance (similar to narcotics) regardless of prescription and possession of even a few pills can lead to imprisonment.

In Japan, modafinil is Schedule I psychotropic drug.[154][155] Cephalon licensed Alfresa Corporation to produce, and Mitsubishi Tanabe Pharma to sell modafinil products under the trade name Modiodal in Japan.[156] There have been arrests of people who imported modafinil for personal use.[157][158]

Modafinil is considered a stimulant doping agent and as such is prohibited in sports competitions. It is in the same category as steroids.[159] Due to laws passed in 2022, import into the country or selling is considered a felony and can be punished with jail time from three to seven years.[160] Simple possession for personal use is punished with a fine and confiscation.

In Russia, modafinil is Schedule II controlled substance like cocaine and morphine. Possession of few modafinil pills can lead to three to ten years imprisonment.[161]

In Sweden, modafinil is classified as a schedule IV substance; possession is illegal without prescription.[162]

Modafinil is classified as a Schedule IV controlled substance under United States federal law.[6] It is illegal to import by anyone other than a DEA-registered importer without a prescription.[163] The Clinton administration issued regulations in 64 FR 4050 effective January 27, 1999, based upon a recommendation of the administration's Assistant Secretary for Health.[164]

A person may legally bring modafinil into the United States in person from a foreign country, provided that he or she has a prescription for it, and the drug is properly declared at the border crossing. U.S. residents are limited to 50 dosage units (e.g., pills).[165] Under the US Pure Food and Drug Act, drug companies are not allowed to market their drugs for off-label uses (treatments of conditions other than those officially approved by the FDA);[166] Cephalon was reprimanded in 2002 by the FDA because its promotional materials were found to be "false, lacking in fair balance, or otherwise misleading".[167] Cephalon pleaded guilty to a criminal violation and paid several fines, including $50 million and $425 million fines to the U.S. government in 2008.[168][169]

The following countries do not classify modafinil as a controlled substance:

• In Finland, modafinil is a prescription drug but not listed as a controlled substance.[170]
• In Denmark, modafinil is a prescription drug but not listed as a controlled substance.[171]
• Mexico (Not listed as a controlled substance, in the National Health Law. Can be purchased in pharmacies without prescription.)[172]
• South Africa Schedule V[173]
• United Kingdom (not listed in Misuse of Drugs Act so possession is not illegal, but a prescription is required) [174]

Modafinil has been studied in the treatment of major depressive disorder.[182][183][184][185][186][187][188][189] In a 2021 systematic review and meta-analysis of randomized controlled trials of psychostimulants for depression, modafinil and other stimulants such as methylphenidate and amphetamines improved depression in traditional meta-analysis.[189] However, when subjected to network meta-analysis, modafinil and most other stimulants did not significantly improve depression, with only methylphenidate remaining effective.[189] Modafinil and other stimulants likewise did not improve quality of life in the meta-analysis, although there was evidence for reduced fatigue and sleepiness with modafinil and other stimulants.[189] While significant effectiveness of modafinil for depression has been reported,[183][185][188] reviews and meta-analyses note that the effectiveness of modafinil for depression is limited, the quality of available evidence is low, and more research is needed.[182][184][186][189]

Modafinil and armodafinil have been repurposed as adjunctive treatments for acute depression in people with bipolar disorder.[113] A 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.[113] Very low rates of mood switch have been observed with modafinil and armodafinil in bipolar disorder.[185]

Modafinil was reported to be effective in the treatment of attention deficit hyperactivity disorder (ADHD), with significantly less abuse potential than conventional psychostimulants like methylphenidate and amphetamines.[12][190] In the United States, an application to market modafinil for pediatric ADHD was submitted to the FDA.[60] However, approval was denied due to concerns about rare but serious dermatological toxicity (Stevens–Johnson syndrome).[60] Modafinil may be used off-label in the US to treat ADHD in both children and adults.[191][12][192] However, evidence of modafinil for treatment of adult ADHD is mixed, and a 2016 systematic review of alternative drug therapies for adult ADHD could not recommend its use in this context.[193] In a large phase 3 clinical trial of modafinil for adult ADHD, modafinil was not effective in improving symptoms and there was a high rate of side effects (86%) and discontinuation (47%).[194] The poor tolerability of modafinil in this study was possibly due to the use of excessively high doses (210–510 mg/day).[194]

Modafinil was studied for the treatment of stimulant dependence.[191][60][195][107][72][108][196] The results of the studies are

Modafinil has been studied for the treatment of cocaine addiction. Modafinil binds to the dopamine transporter (DAT) in an open-to-out conformation, differently than cocaine and methylphenidate.[197][198][199] Subjects pre-treated with modafinil report experiencing less euphoria from cocaine administration.[198] Modafinil does not potentiate self-administration of cocaine in pretreated rats.[200]

The mechanism by which modafinil inhibits cocaine self-administration is likely more complex than the simple observation that modafinil occupies the DAT, as drugs like methylphenidate (another dopamine re-uptake inhibitor) fail to reduce cocaine self-administration.[197][201] Atypical DRIs like modafinil that bind to the DAT in an open-to-out conformation often lack abuse potential relative to cocaine-like DAT ligands.[202]

Modafinil and armodafinil were studied as a complement to antipsychotic medications in the treatment of schizophrenia. They showed no effect on positive symptoms or cognitive performance.[203][204] A 2015 meta-analysis found that modafinil and armodafinil may slightly reduce negative symptoms in people with acute schizophrenia, though they do not appear useful for people with the condition who are stable, with high negative symptom scores.[204] Among medications demonstrated to be effective for reducing negative symptoms in combination with anti-psychotics, modafinil and armodafinil are among the smallest effect sizes.[205]

A 2015 review of clinical studies of possible nootropic effects in healthy people found: "...whilst most studies employing basic testing paradigms show that modafinil intake enhances executive function, only half show improvements in attention and learning and memory, and a few even report impairments in divergent creative thinking. In contrast, when more complex assessments are used, modafinil appears to consistently engender enhancement of attention, executive functions, and learning. Importantly, we did not observe any preponderances for side effects or mood changes."[15] A 2019 review of studies of a single-dose of modafinil on mental function in healthy, non-sleep deprived people found a statistically significant but small effect and concluded that the drug has limited usefulness as a cognitive enhancer in non-sleep deprived persons.[14] A 2020 review of the cognitive enhancing potential of methylphenidate, d-amphetamine, and modafinil in healthy individuals across various domains found that modafinil has a small, positive effect on memory updating.[206]

Modafinil has been used off-label in trials with people with post-chemotherapy cognitive impairment, also known as "chemobrain", but a 2011 review found that it was no better than placebo.[207]

General anesthesia is required for many surgeries, but may cause lingering fatigue, sedation, and/or drowsiness after surgery that lasts for hours to days. In outpatient settings in which patients are discharged home after surgery, this sedation, fatigue, and occasional dizziness is problematic. Modafinil has been tested and reported to be effective in one small (N=34) double-blind randomized controlled trial for this use.[191]

Modafinil was studied for use in multiple sclerosis-associated fatigue, but the resulting evidence was weak and inconclusive.[208][209][210] There were two small controlled studies with conflicting results, and no large, long-term, randomized controlled studies.[26] Therefore, the benefit of using for the treatment of multiple sclerosis-related fatigue was not confirmed.[26]

Caution should be exercised in patients who have narcolepsy in comorbidity with postural orthostatic tachycardia syndrome (POTS). Modafinil, like other centrally acting stimulants prescribed for patients in narcolepsy, increases POTS-related autonomic dysfunction and results in tachycardia/arrhythmia side effects in patients with cardiovascular risk factors. Sodium oxybate, a metabolite of GABA, is an alternative drug for stimulant-intolerant patients with POTS.[211]

There is limited research on the potential use of modafinil as an anti-inflammatory agent, even though some studies predict that modafinil may have anti-inflammatory effects.[212][213] Some studies have suggested that modafinil may modulate the production of nitric oxide in various cells, potentially leading to anti-inflammatory effects.[213][214][215][216][213][214] Nitric oxide is a signaling molecule that plays a complex role in inflammation. It is produced by a variety of cells in the body, including immune cells, and can have both pro-inflammatory and anti-inflammatory effects depending on the context.[217][218] In a 2018 study, researchers noticed that modafinil reduced the production of pro-inflammatory cytokines in vitro in mouse brain cells.[219] In a 2020 study, scholars observed modafinil reduced inflammation and oxidative stress in the brains of rats with traumatic brain injury.[220] In a 2023 study, modafinil reduced neuroinflammation in rats induced by propionic acid.[221] In a 2020 in vitro study, using in nonalcoholic hepatitis human cell model, the authors predicted that modafinil may reduce inflammatory and fibrotic progression in the human liver.[222] The results of studies on this subject still need to be more conclusive.[222]