What is the recommended dosage and treatment guidelines for Suvorexant (Suvorexant) for insomnia?

Suvorexant Dosage and Treatment Guidelines for Insomnia

The recommended dosage of suvorexant for insomnia is 10 mg taken once nightly within 30 minutes of going to bed, with at least 7 hours remaining before planned awakening; if the 10 mg dose is well-tolerated but not effective, the dose can be increased to a maximum of 20 mg once nightly. 1

Dosing Recommendations

• Start with the lowest effective dose (10 mg) taken no more than once per night 1
• If the 10 mg dose is well-tolerated but not effective, the dose can be increased to a maximum of 20 mg 1
• Take within 30 minutes of going to bed with at least 7 hours remaining before planned awakening 1
• Time to effect may be delayed if taken with or soon after a meal 1

Special Population Considerations

• Exposure to suvorexant is increased in obese patients compared to non-obese patients, and in women compared to men 1, 2
• In obese women particularly, consider the increased risk of adverse effects before increasing the dose 1
• When used with moderate CYP3A inhibitors, the recommended dose is 5 mg once nightly (generally not exceeding 10 mg) 1
• Suvorexant is not recommended for use with strong CYP3A inhibitors 1
• No dose adjustment is needed for advanced age, renal impairment, or mild-to-moderate hepatic impairment 2

Efficacy for Insomnia

• Suvorexant is indicated for insomnia characterized by difficulties with sleep onset and/or sleep maintenance 1
• The American Academy of Sleep Medicine (AASM) suggests suvorexant primarily for sleep maintenance insomnia with a weak recommendation 3
• At approved doses (≤20 mg), suvorexant:
  • Reduces wake after sleep onset by 16-28 minutes 3, 4
  • Improves total sleep time by approximately 10-22 minutes 3, 4
  • Shows greater efficacy for sleep maintenance than sleep onset at lower doses 3
  • At 20 mg, demonstrates clinically significant reduction in sleep latency 3

Safety and Adverse Effects

• The most common adverse effect is somnolence, occurring in approximately 7% of patients (vs 3% for placebo) 4, 5
• Number needed to harm (NNH) for somnolence is 28 (95% CI 17-82) for suvorexant 15-20 mg 5
• Suvorexant can impair daytime wakefulness and driving skills 1
• Discontinue or decrease the dose in patients who drive if daytime somnolence develops 1
• Less common but notable adverse effects include:
  • Abnormal dreams, sleep paralysis, and suicidal ideation (dose-related and reported to be mild) 2
  • Hallucinations, sleep paralysis, and somnambulism (rare) 6
• Tolerance, withdrawal, and rebound insomnia generally do not occur at recommended doses 6, 7

Treatment Duration and Discontinuation

• Rebound insomnia and withdrawal effects were not observed when suvorexant was discontinued after 3 months or after 12 months of nightly use 5, 7
• Long-term safety has been demonstrated in studies up to 1 year 7

Contraindications and Precautions

• Contraindicated in patients with narcolepsy 1, 2
• Use caution when combining with other CNS depressants; dosage reduction of suvorexant and/or the other drug(s) may be necessary 1
• Metabolized by the hepatic CYP3A system; avoid combination with strong CYP3A inhibitors 1, 2

Clinical Pearls and Pitfalls

• Suvorexant works through a different mechanism than other hypnotics (orexin receptor antagonism) which may provide an alternative for patients who don't respond to or tolerate other medications 2, 5
• The FDA advises using the lowest effective dose to treat symptoms and warning patients about the possibility of next-day impairment 2
• Administration with food delays drug absorption and is not advised 2
• Patients should be monitored for CNS depressant effects, which may persist in some patients for up to several days after discontinuation 1