What is the maximum recommended dose of Belsomra (suvorexant)?

Maximum Dose of Belsomra (Suvorexant)

The maximum recommended dose of Belsomra is 20 mg taken no more than once per night, within 30 minutes of going to bed with at least 7 hours remaining before planned awakening. 1

FDA-Approved Dosing Guidelines

• The recommended starting dose is 10 mg taken once nightly 1
• If the 10 mg dose is well-tolerated but not effective, the dose can be increased to the maximum of 20 mg 1
• The dose should never exceed 20 mg per night 1
• Timing is critical: take within 30 minutes of bedtime with at least 7 hours available for sleep 1
• Absorption is delayed if taken with or soon after meals, reducing effectiveness 1

Special Dosing Considerations

Obese women require particular caution when considering dose escalation above 10 mg, as they experience significantly higher drug exposure and increased risk of adverse effects compared to non-obese patients and men 1

Drug Interactions Requiring Dose Reduction

• With moderate CYP3A inhibitors: Start at 5 mg, generally do not exceed 10 mg 1
• With strong CYP3A inhibitors: Belsomra is not recommended for use 1
• With other CNS depressants: Dosage reduction of Belsomra and/or the other drug(s) may be necessary due to additive effects 1

Clinical Evidence Supporting the 20 mg Maximum

The American Academy of Sleep Medicine evaluated multiple doses in clinical trials and found that while higher doses (30-40 mg) were studied, the FDA restricted approval to a maximum of 20 mg due to safety concerns 2:

• At 20 mg: Clinically significant reduction in sleep latency of 22.3 minutes versus placebo (moderate quality evidence) 2
• At 20 mg: Clinically significant improvement in total sleep time of 49.9 minutes versus placebo 2
• At 20 mg: Reduction in wake after sleep onset of 28 minutes 3

Why Higher Doses Were Not Approved

The FDA rejected the manufacturer's preferred 40 mg dosage due to 4:

• Excessive daytime somnolence
• Driving impairment documented in formal testing
• Possible narcolepsy-like symptoms

Safety Profile at Maximum Dose

• Somnolence occurs in approximately 7% of patients at 20 mg versus 3% with placebo 3
• Discontinuation rates due to adverse events over 3 months: 3-5% at 20/15 mg doses 5, 6
• Patients taking 20 mg should be cautioned against next-day driving due to documented impairment in some individuals 1
• No evidence of withdrawal or rebound insomnia when discontinued after 3 months 5, 6

Critical Safety Warnings

• Never take more than once per night regardless of dose 1
• Contraindicated in patients with narcolepsy 1
• CNS depressant effects may persist for several days after discontinuation 1
• Discontinue or decrease dose if daytime somnolence develops, especially in patients who drive 1