Drug: Belsomra (Suvorexant)
Approved: August 2014.
Mechanism of action: It 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.
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%).