Major Drug Interactions

These interactions may significantly affect how modafinil or other medications work:

MAJOR

Hormonal Contraceptives

Effect: Modafinil may reduce the effectiveness of birth control pills, patches, rings, and implants.

Mechanism: Induces CYP3A4 enzyme, increasing metabolism of contraceptive hormones.

Recommendation: Use alternative or additional contraceptive methods during treatment and for one month after stopping modafinil.

MAJOR

Warfarin

Effect: May increase or decrease warfarin's blood-thinning effects.

Mechanism: Complex effects on warfarin metabolism.

Recommendation: Frequent INR monitoring required; dose adjustments may be necessary.

MAJOR

Cyclosporine

Effect: May decrease cyclosporine blood levels.

Mechanism: Induces CYP3A4, increasing cyclosporine metabolism.

Recommendation: Monitor cyclosporine levels closely; dose adjustment may be needed.

Moderate Drug Interactions

Antiseizure Medications

Phenytoin, Carbamazepine

May increase levels of these medications, potentially causing toxicity. Monitor for signs of toxicity and adjust doses as needed.

Antidepressants

Tricyclic Antidepressants (TCAs)

Modafinil may increase TCA levels. Monitor for increased side effects like drowsiness, dry mouth, or heart rhythm changes.

MAO Inhibitors

Use with extreme caution. May increase risk of hypertensive crisis.

Other Medications

Propranolol

May increase propranolol levels, potentially affecting blood pressure and heart rate.

Ketoconazole

May increase modafinil levels, potentially increasing side effects.

CYP450 Enzyme Interactions

Modafinil affects several liver enzymes that metabolize medications:

CYP3A4 Induction

Modafinil induces this enzyme, which may:

  • Reduce effectiveness of CYP3A4 substrates
  • Affect hormonal contraceptives
  • Impact immunosuppressants
  • Alter certain heart medications

CYP2C19 Inhibition

Modafinil inhibits this enzyme, which may:

  • Increase levels of CYP2C19 substrates
  • Affect some antidepressants
  • Impact certain antiseizure drugs
  • Alter proton pump inhibitor levels

Food and Supplement Interactions

☕ Caffeine

May increase stimulant effects when combined with modafinil. Consider reducing caffeine intake to avoid excessive stimulation, jitteriness, or sleep problems.

🍷 Alcohol

Alcohol may counteract modafinil's wakefulness-promoting effects. Additionally, the combination may impair judgment and coordination more than either substance alone.

🌿 Herbal Supplements

St. John's Wort: May reduce modafinil effectiveness
Ginseng: May increase stimulant effects
Kava: May counteract alertness effects

Interaction Checker Tool

Check Your Medications

Enter medications you're taking to check for potential interactions:

Disclaimer: This tool is for educational purposes only. Always consult your healthcare provider for personalized advice.