In this article, we will discuss about Suvorexant (BELSOMRA®). So, let’s get started.

Suvorexant (BELSOMRA®) is an orexin receptor antagonist indicated for the treatment of insomnia, characterized by difficulties with sleep onset and/or sleep maintenance.

Mechanism of Action

The mechanism of action of suvorexant in the treatment of insomnia is presumed to be through antagonism of orexin receptors. The orexin neuropeptide signaling system plays a role in wakefulness. Blocking the binding of wake-promoting neuropeptides orexin A and orexin B to receptors OX1R and OX2R is thought to suppress wake drive.


Suvorexant binds to orexin receptors, OX1R and OX2R (Ki=0.55 and 0.35 nM, respectively). Antagonism of orexin receptors may also underlie potential adverse effects such as signs of
narcolepsy cataplexy. Genetic mutations in the orexin system in animals result in hereditary narcolepsy; loss of orexin neurons has been reported in humans with narcolepsy.

Evaluation of QTc Interval

The effects of suvorexant on the QTc interval were evaluated in a randomized, placebo-, and active-controlled (moxifloxacin 400 mg) crossover study in healthy subjects (n=53). The upper bound of the one-sided 95% confidence interval for the largest placebo-adjusted, baseline-corrected QTc interval was
below 10 ms based on analysis of suvorexant doses up to 240 mg, 12 times the maximum recommended
dose. BELSOMRA® thus does not prolong the OTC interval to any clinically relevant extent.


The recommended dose for BELSOMRA® is 10 mg, taken no more than once per night. If the 10 mg dose is well-tolerated but not effective, the dose can be increased. The maximum recommended dose of BELSOMRA® (Suvorexant) is 20 mg taken no more than once per night.

Warnings and Precautions

• CNS Depressant Effects and Daytime Impairment: Risk of impaired alertness and motor coordination, including impaired driving risk increases with dose, caution patients taking 20 mg against next day drving and other activities requiring complete mental alertness.
• Worsening of Depression/Suicidal ideation: Worsening of depression or suicidal thinking may occur. Risk increases with dose. Immediately evaluate any new behavioral changes.
• Complex Sleep Behaviors: Behaviors including sleep-walking, sleep-driving, and engaging in other activities while not fully awake may occur. Discontinue immediately if a complex sleep behavior occurs.
• Sleep Paralysis. Hypnagogic/Hypnopompic Hallucinations, and
Cataplexy-like Symptoms: May occur with the use of BELSOMRA®. Risk increases with dose.
• Compromised Respiratory Function: Effect on respiratory function should be considered.
• Need to Evaluate for Co-morbid Diagnoses: Reevaluate it insomnia
persists after 7 to 10 days of treatment.

Adverse Reactions

The most common adverse reaction (reported in 5% or more of patients treated with BELSOMRA® and at least twice the placebo rate) with BELSOMRA® was somnolence.

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