Modafinil

Uses

Modafinil is used to improve wakefulness in adult patients with Obstructive sleep apnea (OSA). Narcolepsy Shift work disorder (SWD).

Modafinil is also used to associated treatment for these conditions: Narcolepsy, Shift-work related sleep disturbance, Somnolence

How Modafinil works

Nuvigil (armodafinil) is a single-isomer of modafini. The exact mechanism of action is unknown. Modafinil belongs to a class of drugs known as eugeroics, which are stimulants that provide long-lasting mental arousal. Pharmacologically, armodafinil does not bind to or inhibit several receptors and enzymes potentially relevant for sleep/wake regulation. Modafinil is not a direct- or indirect-acting dopamine receptor agonist. However, in vitro, both armodafinil and modafinil bind to the dopamine transporter and inhibit dopamine reuptake. [Medilexicon]

Dosage

Modafinil dosage

Adults: Obstructive Sleep Apnea (OSA) & Narcolepsy: 150 mg to 250 mg as a single dose in the morning. Shift Work Disorder (SWD): 150 mg as a single dose approximately 1 hour prior to the start of work shift. Children: Safety and effectiveness in pediatric patients less than 17 years of age have not been established. Elderly: In elderly patients, elimination of Modafinil and its metabolites may be reduced as a consequence of aging. Therefore, consideration should be given to the use of lower doses and close monitoring in this population. Patients with hepatic impairment: In patients with severe hepatic impairment, Modafinil should be administered at a reduced dose. Patients with renal impairment:There is inadequate information to determine safety and efficacy of dosing in patients with severe renal impairment.

Side Effects

The most common side effects of Modafinil are serious rash, including Stevens-Johnson syndrome, angioedema and anaphylaxis reactions, multi-organ hypersensitivity reactions, persistent sleepiness, psychiatric symptoms and some cardiovascular events.

Precaution

Patients should be cautioned about operating an automobile or other hazardous machinery until it is reasonably certain that Modafinil therapy will not adversely affect their ability to engage in such activities. Caution should be taken in treating patients with a history of psychosis, depression or mania. Discontinuation of treatment should be considered if psychiatric symptoms develop. Increased monitoring of heart rate and blood pressure should be exercised. Caution should be exercised when prescribing Modafinil to patients with known cardiovascular disease.

Interaction

The clearance of drugs that are substrates for CYP3A4 or CYP3A5 (e.g., steroidal contraceptives, Cyclosporine, Midazolam and Triazolam) may be increased by Modafinil which results in lower systemic exposure. Dosage adjustment of these drugs should be considered when used concomitantly with Modafinil.

Elimination of drugs that are substrates for CYP2C19 (e.g., Phenytoin, Diazepam, Propranolol, Omeprazole and Clomipramine) may be prolonged by Modafinil which results in higher systemic exposure. Dosage adjustment of these drugs should be considered when used concomitantly with Modafinil.

More frequent monitoring of prothrombin times/ International normalized ratio (INR) should be considered whenever Modafinil is co-administered with Warfarin.

Caution should be used when concomitantly administering MAO inhibitors and Modafinil.

Food Interaction

• Avoid alcohol.
• Exercise caution with grapefruit products. Modafinil is partially metabolized by CYP3A4, and grapefruit is a CYP3A4 inhibitor.
• Exercise caution with St. John's Wort. Modafinil is partially metabolized by CYP3A4, and St. John's Wort is a CYP3A4 inducer.
• Take with or without food. Taking armodafinil with food can delay the Tmax by 2-4 hours.

[Minor] Administration with food may delay the absorption of modafinil (the racemate) and armodafinil (the R-enantiomer) without significantly affecting their overall bioavailability.

According to the product labeling, modafinil's absorption may be delayed by approximately one hour if taken with food.

Similarly, the time to reach peak plasma concentration (Tmax) of armodafinil may be delayed by approximately 2 to 4 hours in the fed state.

Modafinil Drug Interaction

Minor: aripiprazole, aripiprazole, amphetamine / dextroamphetamine, amphetamine / dextroamphetamineUnknown: duloxetine, duloxetine, omega-3 polyunsaturated fatty acids, omega-3 polyunsaturated fatty acids, pregabalin, pregabalin, cyanocobalamin, cyanocobalamin, ascorbic acid, ascorbic acid, cholecalciferol, cholecalciferol, bupropion, bupropion, cetirizine, cetirizine

Modafinil Disease Interaction

Moderate: alcoholism, cardiovascular dysfunction, liver dysfunction, psychiatric complications, bipolar disorders, psychotic disorders

Volume of Distribution

Apparent volume of distribution: 42L.

Elimination Route

Tmax is 2 hours when fasted and can be delayed approximately 2-4 hours by food, potentially affecting the onset of action.

Half Life

Terminal half-life is approximately 15 hours.

Clearance

The oral clearance of armodafinil is approximately 33 mL/min.

Pregnancy & Breastfeeding use

Pregnancy: There are no adequate and well controlled studies of Modafinil in pregnant women. Modafinil should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Lactation: It is not known whether Modafinil or its metabolites are excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Modafinil is administered to a nursing woman.

Contraindication

Contraindicated in patients with known hypersensitivity to Modafinil or any of theexcipients of this product.

Special Warning

Patients with hepatic impairment: In patients with severe hepatic impairment, Modafinil should be administered at a reduced dose.

Patients with renal impairment:There is inadequate information to determine safety and efficacy of dosing in patients with severe renal impairment.

Acute Overdose

There were no overdoses reported in the Modafinil clinical studies. Symptoms of Modafinil overdose are likely to be similar to those of Modafinil which included excitation or agitation, insomnia and slight or moderate elevations in hemodynamic parameters. There is no specific antidote for Modafinil overdose. However, if overdose occurs, it should be managed with primary supportive care.

Interaction with other Medicine

The clearance of drugs that are substrates for CYP3A4 or CYP3A5 (e.g., steroidal contraceptives, Cyclosporine, Midazolam and Triazolam) may be increased by Modafinil which results in lower systemic exposure. Dosage adjustment of these drugs should be considered when used concomitantly with Modafinil. Elimination of drugs that are substrates for CYP2C19 (e.g., Phenytoin, Diazepam, Propranolol, Omeprazole and Clomipramine) may be prolonged by Modafinil which results in higher systemic exposure. Dosage adjustment of these drugs should be considered when used concomitantly with Modafinil. More frequent monitoring of prothrombin times/ International normalized ratio (INR) should be considered whenever Modafinil is co-administered with Warfarin. Caution should be used when concomitantly administering MAO inhibitors and Modafinil.

Storage Condition

Store in a cool (below 25°C) and dry place protected from light.

Innovators Monograph

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