A new kind of sleep drug approved by FDA.


Drug: Belsomra (Suvorexant)

Company: Merck.

Approved: August 2014.


Mechanism of actionIt is an Orexin( hypocretin) receptor antagonist. Orexin is a neurotransmitter which is involved in regulating wakefulness, arousal, and appetite. This drug shows its action by  blocking the Orexin receptor, which results in the suppressing of wakefulness. This drug  blocks the binding of wake promoting neuropeptides Orexin A and Orexin B to receptors OX1R and OX2R, and this is thought to reduce the wakefulness or wake drive.

Bioavailability: 82%

Peak plasma time: 2hours

Protein binding: 99% to human serum albumin.

Metabolism: CYP3A with a minor contribution from CYP2C19.  It produces an inactive metabolite called hydroxy- suvorexant. 

Excretion: it is 66% excreted from feces and 23% from urine.

Half life: about 12 hours.

Dosing and strength: It is in the form of tablets of 5mg, 10mg, 15mg and 20mg. Starting dose is 10mg PO and should be taken not more than once per night and within 30 minutes of going to bed, with at least 7 hours remaining before the scheduled time of awakening. More than 20mg shouldn’t be consumed once daily.

Pregnancy category: C

 Contraindicated: in Narcolepsy.

Adverse effects: commonly experienced ones are; somnolence, headache, dizziness.  Rarely cough, upper respiratory tract infection and dry mouth ( in 2%). 


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s