Mechanism: alpha-4, beta-2 selective nicotinic acetylcholine receptor (nAchR) partial agonist
Patients with pre-existing psychiatric disorder are at increased risk, but these reactions may occur in patients without any prior history of comorbid psychiatric disorders.
Adverse effects include:
(1) worsening of depression or anxiety
(2) suicidal thoughts or actions
(3) violence towards others and/or hostility
(4) hallucinations
(5) bizarre and vivid dreams
(6) changes in behavior, including mania
(7) agitation or restlessness
(8) mental confusion
(9) impulsivity
(10) paranoia
(11) insomnia
(12) fatigue
Differential diagnosis:
(1) effects of nicotine withdrawal
(2) pre-existing mental disorder
Varenicline is implicated if the symptoms appear or worsen while on varencline but disappear or improve when it is stopped.
Karam-Hage et al reported a patient whose symptoms improved by the addition of buproprion SR while taking varenicline.
