Compositions, and methods of use thereof, are provided for the prevention or treatment of side effects associated with the use of drugs that act as 5HT2 / 5HT3
serotonin receptor antagonists and alpha-2
adrenergic receptor antagonists (5HT2 / 5HT3
antagonist / alpha-2
antagonist). The method involves using
dopamine-releasing compounds, such as
amantadine, anticonvulsants, such as
zonisamide, or
dopamine /
norepinephrine reuptake inhibitors, such as
bupropion, in combination with 5HT2 / 5HT3
antagonist / alpha-2 antagonists, such as
mirtazapine, to reduce the excessive
daytime drowsiness and / or
weight gain associated with 5HT2 / 5HT3 antagonist / alpha-2 antagonist use for the treatment of disorders, such as, depression,
schizophrenia,
anxiety disorders, sleep-related
breathing disorders,
insomnia,
migraine headache, chronic tension-type headache, hot flashes, lower
back pain,
neuropathic pain and functional somatic syndromes. Formulations of
dopamine-releasing compounds or anticonvulsants with 5HT2 / 5HT3 antagonist / alpha-2 antagonists are provided. In particular embodiments,
combination therapy with
mirtazapine and
zonisamide provides relief from chronic
low back pain, while reducing or avoiding side effects associated with monotherapy with
mirtazapine or
zonisamide.