Modafinil: uses, side effects and safety
Modafinil (Modafinil) is a wakefulness-promoting agent; stimulant (schedule iv). It is a US Schedule IV controlled substance. It is prescription only (rx) and remains on the US market.
What is Modafinil?
Modafinil is the generic name for Modafinil, and belongs to the Wakefulness-promoting agent; stimulant (Schedule IV) class.
| Generic name | modafinil |
|---|---|
| Brand name(s) | Modafinil |
| Drug class | Wakefulness-promoting agent; stimulant (Schedule IV) |
| US legal status | US Schedule IV · Prescription only (Rx) |
| Route | Oral |
| Prescription required | Yes |
| Elimination half-life | Approximately 15 hours (effective elimination half-life after multiple doses); modafinil sulfone approximately 40 hours |
| Time to peak concentration | 2-4 hours |
| Metabolism | Metabolized to modafinil acid and modafinil sulfone. CYP3A enzymes are partially involved in metabolic elimination, with auto-induction of CYP3A4 observed in vitro and in vivo; the most rapid metabolic pathway is non-CYP-related (amide hydrolysis). |
What is Modafinil used for?
Modafinil is approved by the FDA for the following uses. Approval is granted per indication, and a specific product may not be approved for all of them.
- Excessive sleepiness associated with narcolepsy in adults
- Excessive sleepiness associated with obstructive sleep apnea (OSA) in adults
- Excessive sleepiness associated with shift work disorder (SWD) in adults
How does Modafinil work?
The mechanism(s) through which modafinil promotes wakefulness is unknown. Wake-promoting actions similar to sympathomimetic agents including amphetamine and methylphenidate; binds to the dopamine transporter and inhibits dopamine reuptake but is not a direct- or indirect-acting dopamine receptor agonist..
It is metabolised primarily by Metabolized to modafinil acid and modafinil sulfone. CYP3A enzymes are partially involved in metabolic elimination, with auto-induction of CYP3A4 observed in vitro and in vivo; the most rapid metabolic pathway is non-CYP-related (amide hydrolysis)..
The elimination half-life is roughly Approximately 15 hours (effective elimination half-life after multiple doses); modafinil sulfone approximately 40 hours. Longer half-lives mean the drug and its active metabolites persist in the body for longer after the last dose.
Common side effects of Modafinil
These are the side effects people report most often. Many diminish after the body adjusts, usually within one to two weeks.
- Headache
- Nausea
- Nervousness
- Rhinitis
- Diarrhea
- Back pain
- Anxiety
- Insomnia
- Dizziness
- Dyspepsia
What does Modafinil interact with?
Interactions matter because two safe medicines can become dangerous together. The entries below are the ones most likely to cause harm.
- CYP3A4/5 substrates (steroidal contraceptives, cyclosporine, midazolam, triazolam): clearance may be increased by enzyme induction, lowering systemic exposure
- Steroidal contraceptives: effectiveness may be reduced during treatment and for one month after discontinuation - alternative or concomitant contraception recommended
- Potent CYP3A4/5 inducers (carbamazepine, phenobarbital, rifampin) and inhibitors (ketoconazole, erythromycin): may alter plasma concentrations
Use our drug interaction checker before combining any two prescriptions.
Serious side effects and warning signs
Seek emergency care for any of these
- Severe rash and serious multiorgan hypersensitivity (e.g. DRESS)
- Angioedema
- Psychosis, hallucinations and suicidal ideation
- Stevens-Johnson syndrome, toxic epidermal necrolysis and erythema multiforme
- Amlodipine / potent CYP3A4 co-administration effects requiring dose adjustment
Suspected overdose or a bad reaction should be reported to Poison Control on 1-800-222-1222. That is staffed around the clock and is free.
Legal status of Modafinil
Modafinil is a Schedule IV controlled substance in the United States. That placement is set out in Title 21 of the Code of Federal Regulations, Part 1308, and enforced by the Drug Enforcement Administration. It carries restrictions on prescribing, storage, record-keeping and transfer.
Statutory reference: 21 CFR 1308.14(f)(7) - Modafinil (DEA code 1680); label also states modafinil tablets contain modafinil, a Schedule IV controlled substance.
Important note
Onset null because the label gives an administration window (~1 hour before the start of the work shift for SWD), not an onset-to-effect time, and MedlinePlus gives no onset figure. Peak plasma concentrations occur at 2-4 hours, so peakHours is stored as a string range. Food delays tmax by approximately one hour but has no effect on overall bioavailability. OSA indication treats the excessive sleepiness only, not the underlying obstruction. Label states modafinil is federally a C-IV because it can be abused or lead to dependence, and produced psychoactive and euphoric effects in an abuse-potential study.
Can you get Modafinil without a prescription?
Short answer: no. Modafinil is a prescription medication. Sites advertising it without one are either operating illegally or selling something other than what they claim. We explain the legal routes, the counterfeit problem and how to check a source in detail.
Read the full answer: Modafinil without a prescription →
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Read more →Frequently asked questions
What is Modafinil used for?
Excessive sleepiness associated with narcolepsy in adults Excessive sleepiness associated with obstructive sleep apnea (OSA) in adults Excessive sleepiness associated with shift work disorder (SWD) in adults
What schedule is Modafinil in the United States?
Modafinil is a Schedule IV controlled substance in the US, listed at 21 CFR Part 1308. Schedule IV means the drug has a defined potential for abuse and is subject to federal record-keeping, storage and prescribing restrictions.
What are the common side effects of Modafinil?
The most frequently reported side effects are headache, nausea, nervousness, rhinitis, diarrhea, back pain. Many lessen over the first week or two of treatment.
What should not be combined with Modafinil?
The most clinically important interactions are with cyp3a4/5 substrates (steroidal contraceptives, cyclosporine, midazolam, triazolam): clearance may be increased by enzyme induction, lowering systemic exposure, steroidal contraceptives: effectiveness may be reduced during treatment and for one month after discontinuation - alternative or concomitant contraception recommended, potent cyp3a4/5 inducers (carbamazepine, phenobarbital, rifampin) and inhibitors (ketoconazole, erythromycin): may alter plasma concentrations. Always give a pharmacist or prescriber a complete list of everything you take, including over-the-counter drugs and supplements.
Sources & references
Important
This site provides educational information only and does not sell, prescribe or dispense medications. Always consult a licensed healthcare provider. This page is not medical advice.