A reference work, not a recommendation to use: this profile describes mechanism and evidence and does not replace medical advice. The claims come from marketing and forums and are tested here, not endorsed.

Mechanism of action

Evidence map: Armodafinil

Each line stands for a published finding; line style and color show where it comes from. The filter hides weaker evidence levels. Sources: see references.

Armodafinil is the R form of the racemate modafinil. Both enantiomers bind to the dopamine transporter and inhibit dopamine reuptake more weakly than cocaine; R-modafinil has about three times higher affinity than S-modafinil [1]. Experiments with transporter mutants suggest that both enantiomers tolerate an inward-open conformation of the transporter better than cocaine does, that is, they bind differently. In microdialysis in mice, R-modafinil raised dopamine in the shell of the nucleus accumbens less strongly than cocaine, but for longer [1]. For the racemate, PET in humans has shown that it occupies dopamine transporters and raises dopamine in the striatum [2]; a corresponding PET study specifically with armodafinil was not found.

The practical difference from the racemate lies in the pharmacokinetics. The half-life is the same at about 13 hours, but S-modafinil is cleared rapidly at the start; as a result, levels fall off biphasically after modafinil and monophasically after armodafinil, and per milligram the total exposure (AUC) is about 40% higher with armodafinil [3]. In three open-label studies in healthy people, armodafinil moderately induced the enzyme CYP3A4 and moderately inhibited CYP2C19, but did not affect CYP1A2 [4].

Synaptik serves solely to explain biochemistry and pharmacology and is not medical advice or a recommendation to take anything.

Mechanism of action only. Schematic cross-section of a striatal dopaminergic synapse with a neighbouring noradrenergic terminal, plus an inset with a serotonergic terminal on the left; not to scale. Particle numbers, speeds and the bars of the live readout come from an illustrative model, not from measurements. Only for methylphenidate and modafinil does the share of blocked dopamine transporters (6 and 5 of 10) match a rounded PET occupancy, from two different studies; all other shares are illustrative.

DAT: blocked by armodafinil (share illustrative) · dopamine lingers

DAT
inhibited≈ 3-fold higher affinity than S-modafinil (cells)
NET
not shown
SERT
not shown
synthesis (TH, AADC)
unchanged
dopamine in the cleft (model)
moremicrodialysis, mouse
Drug
View

dopamine  noradrenaline  serotonin  cAMP  drug  cross = transporter blocked

Armodafinil is the R-enantiomer of modafinil. Both enantiomers inhibit dopamine uptake at human DAT less potently than cocaine; R-modafinil binds about three times more strongly than S-modafinil. In mice, both raised dopamine in the nucleus accumbens shell, less than cocaine and for longer [21]. The profile lists no PET study of armodafinil itself; the share of blocked transporters is illustrative.

Tap or focus a labelled part for a short explanation.

Also acting here, not drawn

  • Flmodafinil: DAT inhibition only from unpublished commissioned data (evidence level 0)
  • Saffron: at SERT only a computer simulation (docking), no measured binding or inhibition

What the figure shows, and how sure we are

Mechanism-of-action explainer only. Not medical advice, and no statement about benefit, risk, amount or use; each profile gives the legal status.

What was simplified. One terminal and one cleft stand for a striatal dopamine synapse; sizes, cleft width, numbers of vesicles, transporters and receptors, and all speeds are illustrative. Drugs are drawn on the outside of the transporter, not at their binding sites. The positions of TH, AADC and COMT are schematic. The occupancy values for methylphenidate and modafinil come from two studies with different amounts, brain regions and participants and are not directly comparable; the values for the other drugs come from cells, synaptosomes or animal studies. The numbers in [14] to [28] are in the Synaptik profiles of the drugs, where they were checked against the abstracts; [1] to [13] and [29] were checked on PubMed for this figure (26 Oct 2026), [2] bibliographically only.

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Targets

TargetTypeActionKey dataEvidence
Dopamine transporter (DAT)TransporterInhibitorabout 3-fold higher affinity than S-modafinil (human DAT, cell culture) Animal study[1]
CYP3A4EnzymeExpression ↑AUC of oral midazolam lowered by ≈ 32% (healthy people, open-label) Human, non-randomised[4]
CYP2C19EnzymeInhibitorAUC of omeprazole raised by ≈ 38% (healthy people, open-label) Human, non-randomised[4]

Effect profile

Which signaling systems the compound affects according to current data. ↑ enhanced, ↓ dampened, ≈ modulated, ○ no effect; dots = evidence level.

  • Dopamine↑ · Inhibits the dopamine transporter; dopamine raised in the nucleus accumbens (mouse); in humans shown by PET for the racemate only[1][2]
  • Noradrenalineno data
  • Serotoninno data
  • Acetylcholineno data
  • Glutamate · AMPAno data
  • Glutamate · NMDAno data
  • GABAno data
  • Histamineno data
  • Orexinno data
  • Adenosineno data
  • Opioidsno data
  • Melatoninno data
  • Neurotrophinsno data
  • Blood flowno data
  • Nitric oxideno data
  • Energy metabolismno data
  • Insulin · glucoseno data
  • Inflammation · oxidativeno data
  • Stress axisno data
  • Testosterone axisno data
  • Endocannabinoidsno data
  • Autophagy · senescenceno data
  • Immune systemno data
  • Lipid metabolismno data
  • Coagulation · fibrinolysisno data
  • Methylationno data

Human studies

  • Wakefulness during nocturnal sleep deprivation

    RCT, double-blind, placebo- and active-controlled (modafinil) · healthy (men) · n = 107 · Single dose, one night

    Measured: Maintenance of Wakefulness Test and Psychomotor Vigilance Task

    Result: All strengths lengthened sleep latency and reduced attention lapses; effective for longer than modafinil 6–14 hours after dosing.[6]

    Human, randomised

  • Active control in a study of lisdexamfetamine

    RCT, double-blind, placebo-controlled · healthy (men) · n = 135 · Single dose, 24 hours of sleep deprivation

    Measured: Maintenance of Wakefulness Test

    Result: Mean sleep latency 27.6 minutes with armodafinil versus 15.3 minutes with placebo.[7]

    Human, randomised

  • Shift work disorder

    RCT, placebo-controlled, multicenter · Patients: shift work disorder with marked sleepiness · n = 254 · 12 weeks

    Measured: Sleep latency during the night shift, memory, attention

    Result: Sleep latency lengthened from 2.3 to 5.3 minutes (placebo 2.4 to 2.8); memory and attention tests better than with placebo.[8]

    Human, randomised

  • Interactions via CYP enzymes

    three open-label studies (sequential or crossover) · healthy · n = 77 · up to just over 3 weeks

    Measured: Pharmacokinetics of caffeine, midazolam, omeprazole

    Result: No effect on CYP1A2, moderate induction of CYP3A4, moderate inhibition of CYP2C19.[4]

    Human, non-randomised

Risks and warnings

  • Common side effects

    In one RCT, most commonly abdominal pain, nausea, and headache; also palpitations, higher blood pressure, and poorer sleep efficiency [6].

    Human, randomised

  • Stevens-Johnson syndrome

    Rare, life-threatening skin reaction; listed in the prescribing information, and one case was described in 2018 [9].

    Human, non-randomised

  • Abuse potential

    Mice that had learned to distinguish cocaine from saline classified R-modafinil entirely as cocaine [1]; the racemate raises dopamine in the human nucleus accumbens [2]. No data on dependence in humans specifically for armodafinil were found.

    Animal study

  • Interactions via CYP enzymes

    May lower levels of CYP3A4 substrates and raise levels of CYP2C19 substrates [4].

    Human, non-randomised

Interactions

  • MAO inhibitors (tranylcypromine): Hypertensive crisis after concurrent use in a case report; in the literature review, 2 of 7 patients taking modafinil or armodafinil plus an MAO inhibitor had an adverse reaction [10].
  • Midazolam and other CYP3A4 substrates: AUC of oral midazolam lowered by about 32% [4].
  • Omeprazole and other CYP2C19 substrates: AUC of omeprazole raised by about 38% [4].

Fact check: common claims

  • partly supported

    “Armodafinil lasts longer than modafinil”

    The half-life is the same, but levels remain higher later in the day [3]; under sleep deprivation, wakefulness was better than with modafinil 6–14 hours after dosing [6].

  • not supported

    “Armodafinil improves concentration and memory in well-rested healthy people”

    In healthy people, studied only under sleep deprivation [6][7]; the improvements in memory and attention come from a study in shift work disorder [8].

  • not supported

    “Armodafinil has no addiction potential”

    Mice classified R-modafinil like cocaine [1], and the racemate raises dopamine in the human reward system [2]; dependence data in humans are lacking.

Pharmacokinetics

Absorption
Peak plasma levels similar to modafinil, reached somewhat later in one study [3][6].
Half-life
About 13 hours, as with the racemate; levels remain higher later in the day, however [3].
Metabolism
Moderate inducer of CYP3A4 and moderate inhibitor of CYP2C19 [4].
Entry into the brain
Raises dopamine in the nucleus accumbens of mice [1]; no imaging study of its own found in humans.

Legal status

Germany
Legally unclear. Armodafinil has no entry of its own in Annex 1 of the German Ordinance on Prescription-Only Medicines (AMVV); the annex lists “Modafinil” and explicitly extends the prescription requirement to medicinal products containing salts or hydrates of the listed substances, but it does not mention a single enantiomer [11]. Whether medicinal products containing armodafinil would instead be prescription-only as medicinal products with a substance whose effects are not generally known in medical science, under Section 48(1) sentence 1 no. 2 of the German Medicinal Products Act (AMG), has not been checked [12]. Armodafinil is not listed in Annexes I–III of the German Narcotics Act (BtMG) [13]. How to check: query national marketing authorizations in AMIce/PharmNet and ask the BfArM whether and on what basis (the modafinil entry of the AMVV, Section 48 AMG) a prescription requirement exists; the food-law question is separate and has not been verified.
EU
No centrally authorized product and no risk assessment procedure for armodafinil in the EMA data export (retrieved October 25, 2026); according to a review, not approved by the EMA [5]. National marketing authorizations in other EU member states not checked.
USA
Approved by the FDA as Nuvigil (NDA 021875, approved June 15, 2007, prescription-only); according to the US prescribing information, to improve wakefulness in adults with excessive sleepiness associated with obstructive sleep apnea, narcolepsy, or shift work disorder; classified as Schedule IV [14].

Related compounds

ModafinilracemateAdrafinilanalog (German only)Flmodafinilanalog (German only)

Open questions

  • How strongly does armodafinil itself occupy the dopamine transporter in the human brain?
  • Does armodafinil have any measurable cognitive effect in well-rested healthy people at all?
  • Is the abuse risk different from that of the racemate because of the longer duration of action?

References

  1. Loland CJ, Mereu M, Okunola OM, Cao J, Prisinzano TE, Mazier S, et al. R-modafinil (armodafinil): a unique dopamine uptake inhibitor and potential medication for psychostimulant abuse. Biol Psychiatry. 2012;72(5):405–13. doi:10.1016/j.biopsych.2012.03.022 · PubMed
  2. Volkow ND, Fowler JS, Logan J, Alexoff D, Zhu W, Telang F, et al. Effects of modafinil on dopamine and dopamine transporters in the male human brain: clinical implications. JAMA. 2009;301(11):1148–54. doi:10.1001/jama.2009.351 · PubMed
  3. Darwish M, Kirby M, Hellriegel ET, Robertson P Jr. Armodafinil and modafinil have substantially different pharmacokinetic profiles despite having the same terminal half-lives: analysis of data from three randomized, single-dose, pharmacokinetic studies. Clin Drug Investig. 2009;29(9):613–23. doi:10.2165/11315280-000000000-00000 · PubMed
  4. Darwish M, Kirby M, Robertson P Jr, Hellriegel ET. Interaction profile of armodafinil with medications metabolized by cytochrome P450 enzymes 1A2, 3A4 and 2C19 in healthy subjects. Clin Pharmacokinet. 2008;47(1):61–74. doi:10.2165/00003088-200847010-00006 · PubMed
  5. Biscarini F, Barateau L, Pizza F, Plazzi G, Dauvilliers Y. Present and future of central disorders of hypersomnolence. J Sleep Res. 2025;34(5):e70118. doi:10.1111/jsr.70118 · PubMed
  6. Dinges DF, Arora S, Darwish M, Niebler GE. Pharmacodynamic effects on alertness of single doses of armodafinil in healthy subjects during a nocturnal period of acute sleep loss. Curr Med Res Opin. 2006;22(1):159–67. doi:10.1185/030079906X80378 · PubMed
  7. Gasior M, Freeman J, Zammit G, Donnelly P, Gao J, Ferreira-Cornwell MC, et al. Maintenance of wakefulness with lisdexamfetamine dimesylate, compared with placebo and armodafinil in healthy adult males undergoing acute sleep loss. J Clin Psychopharmacol. 2014;34(6):690–6. doi:10.1097/JCP.0000000000000202 · PubMed
  8. Czeisler CA, Walsh JK, Wesnes KA, Arora S, Roth T. Armodafinil for treatment of excessive sleepiness associated with shift work disorder: a randomized controlled study. Mayo Clin Proc. 2009;84(11):958–72. doi:10.1016/S0025-6196(11)60666-6 · PubMed
  9. Holfinger S, Roy A, Schmidt M. Stevens-Johnson syndrome after armodafinil use. J Clin Sleep Med. 2018;14(5):885–7. doi:10.5664/jcsm.7132 · PubMed
  10. Kinslow CJ, Shapiro SD, Grunebaum MF, Miller EC. Acute hypertensive crisis and severe headache after concurrent use of armodafinil and tranylcypromine: case report and review of the literature. J Neurol Sci. 2018;393:1–3. doi:10.1016/j.jns.2018.07.023 · PubMed
  11. Verordnung über die Verschreibungspflicht von Arzneimitteln (Arzneimittelverschreibungsverordnung – AMVV), Anlage 1 (zu § 1 Nr. 1 und § 5). Bundesministerium der Justiz [Internet]. Abgerufen am 25.10.2026. Verfügbar unter: https://www.gesetze-im-internet.de/amvv/anlage_1.html
  12. Gesetz über den Verkehr mit Arzneimitteln (Arzneimittelgesetz – AMG), § 48 Verschreibungspflicht. Bundesministerium der Justiz [Internet]. Abgerufen am 25.10.2026. Verfügbar unter: https://www.gesetze-im-internet.de/amg_1976/__48.html
  13. Gesetz über den Verkehr mit Betäubungsmitteln (Betäubungsmittelgesetz – BtMG), Anlagen I bis III (zu § 1 Abs. 1). Bundesministerium der Justiz [Internet]. Abgerufen am 25.10.2026. Verfügbar unter: https://www.gesetze-im-internet.de/btmg_1981/anlage_i.html (Anlage II und III unter anlage_ii.html bzw. anlage_iii.html)
  14. U.S. Food and Drug Administration. Drugs@FDA: Nuvigil (armodafinil), NDA 021875, und US-Fachinformation Nuvigil (SPL, Abschnitte 1 und 9.1) [Internet]. Silver Spring (MD): FDA; abgerufen über die openFDA-Schnittstelle am 25.10.2026. Verfügbar unter: https://www.accessdata.fda.gov/scripts/cder/daf/
How this profile was checked

Last reviewed: 2026-10-25. All sources with a DOI or PMID were resolved automatically via Crossref or doi.org and PubMed.

Translated from the German profile (version of 2026-10-25); translation checked on 2026-10-26.

Checked

  • October 25, 2026 (decisions q119/E-17 and q040): legal status checked against primary sources and worded as “legally unclear” with a way to check. AMVV Annex 1 in full text (“gesetze-im-internet.de”): no entry “Armodafinil”, entry “Modafinil”, the preamble extends the prescription requirement to salts and hydrates [11]; Section 48(1) sentence 1 no. 2 AMG read in the statutory text [12]; BtMG Annexes I–III without an entry [13]; EMA medicines and referrals data export (timestamp October 24, 2026) without armodafinil; openFDA (Drugs@FDA): Nuvigil NDA 021875, ORIG approved on June 15, 2007, “Prescription”; openFDA label for Nuvigil: indication (OSA, narcolepsy, shift work disorder) and “Schedule IV controlled substance” [14]. `rx_referenz` set because the prescription requirement is documented in the US; in Germany it is not documented (see status). Summary and evmap node “Armodafinil” aligned with status.eu (“not centrally authorized in the EU”; national marketing authorizations neither documented nor ruled out).
  • October 25, 2026 (q012): the ratings in `versprechen` and `behauptungen` are based only on the abstracts of the studies [1][2][3][4][6][7][8][9][10] (abstract only checked); full text only for [5].
  • All 10 DOIs resolved via Crossref and all PMIDs via PubMed with tools/pruefe_profile.py.
  • Key figures checked against the abstracts: R ≈ 3-fold higher DAT affinity, microdialysis, cocaine discrimination [1]; t½ ≈ 13 h, monophasic vs. biphasic, AUC +33%/+40% [3]; n = 77 (29/24/24), CYP1A2 without effect, midazolam AUC −17%/−32%, omeprazole +38% [4]; n = 107, effect 6–14 h, side effects [6]; n = 135, MWT 27.6 vs. 15.3 min [7]; n = 254, latency 2.3 → 5.3 vs. 2.4 → 2.8 min [8]; case report of SJS [9]; 2 of 7 patients with an MAO inhibitor [10].
  • In the full text (Europe PMC): “armodafinil and amphetamine derivatives are approved by the FDA only” [5].
  • ClinicalTrials.gov: 62 entries for armodafinil (October 23, 2026).
  • October 25, 2026, trade names harmonized (q018; guideline section “Handelsnamen”, decision of October 25, 2026: the Article 57 database counts as a source on a par with the EPAR, the summary of product characteristics and Drugs@FDA; US names only where there are no DE/EU names; no combination products): synonyms unchanged. The EMA database under Article 57 (Article 57 product data, EMA/518502/2018 Rev. 90, data as of October 9, 2026, retrieved October 25, 2026) lists no product with the active substance armodafinil, and the EMA export contains none (see above); there is therefore no DE/EU trade name, and the US name “Nuvigil” (Drugs@FDA NDA 021875, see above) stays under the rule.

Not verified

  • National marketing authorizations in Germany (AMIce/PharmNet) not queried; whether and on what basis (AMVV entry “Modafinil”, Section 48 AMG) a prescription requirement exists has not been clarified by the authorities (legally unclear, how to check in status).
  • The Schedule IV classification rests on the US prescribing information [14]; the DEA list itself was not retrieved.
  • No study on cognition in well-rested healthy people found (PubMed search “armodafinil” with “healthy” and “cognition/memory”); one review claims improvements in healthy people, but I could not identify the underlying studies.

No dosages, no sources of supply. This information does not replace medical advice.

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