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Suvorexant

Generic Name: Suvorexant

Brand Names: Belsomra

Suvorexant is the first approved orexin receptor antagonist for insomnia treatment.

NeurologicSleep

Drug Class

Orexin Receptor Antagonist (Dual Orexin Receptor Antagonist — DORA)

DEA Schedule

Schedule Schedule IV

Pregnancy

Not formally categorized; limited human data — use during pregnancy only if clearly needed

Available Forms

5 mg oral tablet, 10 mg oral tablet, 15 mg oral tablet, 20 mg oral tablet

Dosage Quick Reference

These are general dosage guidelines. Your doctor will determine the appropriate dose for your specific situation.

ConditionStarting DoseTypical Maintenance Dose
Insomnia — difficulty with sleep onset10 mg once nightly, within 30 minutes of bedtime10–20 mg once nightly (max 20 mg)
Insomnia — difficulty with sleep maintenance10 mg once nightly, within 30 minutes of bedtime10–20 mg once nightly (max 20 mg)
Insomnia with moderate CYP3A4 inhibitor use5 mg once nightly5 mg once nightly (do not exceed)

Side Effects

Common Side Effects:

  • Somnolence (next-day drowsiness)
  • Headache
  • Dizziness
  • Abnormal dreams
  • Dry mouth
  • Cough
  • Upper respiratory tract infection

Serious Side Effects:

  • Complex sleep behaviors (sleepwalking, sleep-driving)
  • Sleep paralysis
  • Hypnagogic/hypnopompic hallucinations
  • Suicidal ideation
  • Cataplexy-like symptoms

Drug Interactions

Major Drug & Food Interactions

  • Strong CYP3A4 inhibitors (ketoconazole, itraconazole, clarithromycin, ritonavir): Contraindicated — dramatically increases suvorexant levels and risk of excessive sedation and CNS depression.
  • Moderate CYP3A4 inhibitors (erythromycin, fluconazole, diltiazem, verapamil, grapefruit juice): Reduce suvorexant dose to 5 mg nightly; monitor for excessive sedation.
  • CNS depressants (benzodiazepines, opioids, other sedative-hypnotics, alcohol): Additive CNS depression; increased risk of next-day impairment, excessive sleepiness, respiratory depression, and complex sleep behaviors.
  • Strong CYP3A4 inducers (rifampin, carbamazepine, phenytoin): May substantially reduce suvorexant effectiveness; monitor therapeutic response.
  • Digoxin: Suvorexant may increase digoxin levels; monitor digoxin serum concentrations when co-administered.

Additional Information

Suvorexant is a dual orexin receptor antagonist (DORA) used to treat insomnia characterized by difficulty with sleep onset and/or sleep maintenance. It represents a novel mechanism for treating insomnia by blocking wake-promoting orexin signaling.

Mechanism of Action

Suvorexant works by antagonizing orexin receptors:

  • Dual orexin receptor antagonism: Blocks both OX1R and OX2R receptors
  • Suppresses wake drive: Orexins A and B promote and maintain wakefulness
  • Promotes natural sleep: Reduces orexin-driven arousal without sedation
  • Preserves sleep architecture: May maintain more normal sleep stages than GABA-targeting drugs

Orexin neurons are most active during wakefulness and silent during sleep.

Available Formulations

Suvorexant is available as tablets:

  • 5 mg, 10 mg, 15 mg, 20 mg tablets

Medical Uses

FDA-Approved Indication:

  • Treatment of insomnia characterized by difficulties with sleep onset and/or sleep maintenance

Suvorexant improves both time to fall asleep and total sleep time.

Dosing Guidelines

Adults:

  • Starting dose: 10 mg once nightly within 30 minutes of bedtime
  • May increase to 20 mg if 10 mg is tolerated but not effective
  • Maximum: 20 mg nightly

Time Requirements:

  • Take within 30 minutes of going to bed
  • Allow at least 7 hours before planned awakening

With CYP3A4 Inhibitors:

  • Moderate CYP3A4 inhibitors: Start at 5 mg; max 10 mg
  • Strong CYP3A4 inhibitors: Avoid use

Important Safety Information

Controlled Substance:

  • Schedule IV controlled substance

Contraindications:

  • Narcolepsy

Warnings and Precautions:

  • CNS depressant effects: Impaired alertness and motor coordination, including next-day impairment
  • Sleep paralysis, hypnagogic/hypnopompic hallucinations: May occur
  • Complex sleep behaviors: Sleepwalking, sleep-driving, and other activities while not fully awake (discontinue if occurs)
  • Worsening of depression/suicidal ideation: Monitor patients with depression
  • Compromised respiratory function: Use with caution in patients with respiratory impairment
  • Cataplexy-like symptoms: Possible in susceptible individuals

Drug Interactions

Strong CYP3A4 Inhibitors (ketoconazole, itraconazole, clarithromycin, ritonavir):

  • Avoid concomitant use

Moderate CYP3A4 Inhibitors (diltiazem, erythromycin, fluconazole):

  • Start at 5 mg; max 10 mg

Strong CYP3A4 Inducers (rifampin, carbamazepine, phenytoin):

  • May reduce efficacy substantially

Other CNS Depressants (alcohol, opioids, benzodiazepines):

  • Additive CNS depression; use with caution

Digoxin:

  • Suvorexant may increase digoxin levels; monitor

Special Populations

  • Hepatic Impairment:
    • Mild to moderate: No adjustment
    • Severe: Not recommended
  • Renal Impairment: No adjustment needed
  • Elderly: No specific adjustment; consider 5 mg starting dose
  • Pregnancy: Limited data; not recommended
  • Lactation: Unknown if excreted in milk
  • Pediatric: Safety not established

Frequently Asked Questions

Unlike benzodiazepines or Z-drugs (zolpidem, eszopiclone) that enhance GABA to sedate the brain, suvorexant works by blocking orexin receptors. Orexins are brain chemicals that promote wakefulness. By blocking these signals, suvorexant reduces the "wake drive" rather than forcefully sedating the brain. This mechanism more closely mimics the natural transition to sleep.
Next-day drowsiness is possible, especially at higher doses. The 20 mg dose carries a higher risk of next-morning impairment. Start with 10 mg and ensure you have at least 7 hours available for sleep. If morning grogginess persists, your doctor may lower your dose.
Suvorexant is classified as a DEA Schedule IV controlled substance, indicating it has some potential for abuse and dependence — though this risk is considered lower than with traditional benzodiazepine sleep aids. Clinical studies showed minimal withdrawal symptoms upon discontinuation and low abuse potential overall.
While there is no specific contraindication, combining suvorexant with melatonin has not been well studied. Both promote sleep through different mechanisms. Discuss any supplements, including melatonin, with your doctor to avoid excessive sedation.
Complex sleep behaviors include sleepwalking, sleep-driving, and performing other activities while not fully awake. These are rare but have been reported with orexin receptor antagonists. If you or a family member notice any unusual nighttime activities, stop the medication and contact your doctor immediately.

Medical Disclaimer: This information is for educational purposes only and should not be considered medical advice. Always consult with your healthcare provider before starting, stopping, or changing any medication. Your doctor can provide personalized recommendations based on your specific health condition and medical history.

Questions About This Medication?

Talk to your doctor or pharmacist about whether Suvorexant is right for you.

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