Dosing and uses of Belsomra (suvorexant)
Adult dosage forms and strengths
tablet: Schedule IV
- 5mg
- 10mg
- 15mg
- 20mg
Insomnia
Indicated for insomnia characterized by difficulties with sleep onset and/or sleep maintenance
Recommended starting dose: 10 mg PO taken no more than once per night and within 30 minutes of going to bed, with at least 7 hr remaining before the planned time of awakening
Use the lowest dose effective for the patient If 10 mg dose is well-tolerated but not effective, the dose can be increased
Not to exceed 20 mg once daily
Dosage modifications
Renal impairment: No dosage adjustment required
Hepatic impairment
- Mild-to-moderate: No dosage adjustment required
- Severe: Not recommended
Coadministration with CYP3A4 inhibitors
- Strong: Not recommended
- Moderate: Decrease suvorexant recommended dose to 5 mg PO HS; if tolerated but not effective, may increase dose, not to exceed 10 mg/dose
Dosing Considerations
Systemic exposure increased in obese compared with nonobese patients, and in women compared with men
Particularly in obese women, the increased risk of exposure-related adverse effects should be considered before increasing the dose
Administration
May take with or without food; however, for faster sleep onset, do not administer soon after a meal because food will delay the onset of action
If alcohol consumed in the evening or before bed, do not take suvorexant
Pediatric dosage forms and strengths
Safety and efficacy not established
Geriatric dosage forms and strengths
See adult dosing
Belsomra (suvorexant) adverse (side) effects
1-10%
Somnolence, females (8%)
Somnolence (7%)
Headache (7%)
Somnolence, males (3%)
Dizziness (3%)
Abnormal dreams (2%)
Cough (2%)
Diarrhea (2%)
Dry mouth (2%)
Upper respiratory tract infection (2%)
Warnings
Contraindications
Narcolepsy
Cautions
Can impair daytime wakefulness; CNS depressant effects can last for up to several days after discontinuation
Can impair driving skills and may increase the risk of falling asleep while driving
Patients should not use suvorexant if they drank alcohol that evening or before bed; coadministration with other CNS depressants (eg, benzodiazepines, opioids, tricyclic antidepressants, alcohol) increases the risk of CNS depression
Dosage adjustments of suvorexant and concomitant CNS depressants may be necessary when administered together because of potentially additive effects
Use with other drugs to treat insomnia is not recommended
Risk of next-day impairment, including impaired driving, is increased if taken with less than a full night of sleep remaining, if a higher than the recommended dose is taken, if coadministered with other CNS depressants, or if coadministered with other drugs that increase suvorexant blood levels
Caution patients taking 20 mg to refrain from next-day driving and other activities requiring full mental alertness
Reevaluate patients for comorbid conditions if insomnia persists after 7-10 days of treatment
Cognitive and behavioral changes (eg, amnesia, anxiety, hallucinations, and other neuropsychiatric symptoms) reported with hypnotics; “sleep driving” and other complex behaviors (eg, preparing and eating food, making phone calls, or having sex), with amnesia for the event, have been reported
The use of alcohol and other CNS depressants may increase the risk of cognitive changes listed above; discontinuation should be strongly considered
Dose-dependent increase in suicidal ideation was observed in patients taking suvorexant, as assessed by questionnaire; immediately evaluate patients with suicidal ideation or any new-onset behavioral changes; worsening depression or suicidal thinking, thoughts, and actions have been reported with the use of sedative-hypnotic
Consider effect on respiratory function
Risk of sleep paralysis, hypnagogic/hypnopompic hallucinations, and cataplexy-like symptoms increases with increasing doses
Not recommended for patients with severe hepatic impairment or those taking a strong CYP3A inhibitor
Pregnancy and lactation
Pregnancy category: C
Lactation: Unknown if distributed in human breast milk
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Belsomra (suvorexant)
Mechanism of action
Orexin receptor antagonist; orexin, also called hypocretin, is a neurotransmitter that regulates arousal, wakefulness, and appetite
Blocking the binding of wake-promoting neuropeptides orexin A and orexin B to receptors OX1R and OX2R is thought to suppress wake drive
Absorption
Bioavailability: 82%
Peak plasma time: 2 hr (range 30 min to 6 hr)
Taking after a high-fat meal delays peak concentration by ~1.5 hr
Distribution
Protein bound: >99% to human serum albumin and α1-acid glycoprotein
Not preferentially distribute into RBCs
Vd: 49 L
Metabolism
Mainly eliminated by metabolism, primarily by CYP3A with a minor contribution from CYP2C19
Metabolite: hydroxy-suvorexant (not active)
Elimination
Half-life: ~12 hr
Excretion: 66% feces; 23% urine
