GENERIC NAME: bupropion
DRUG CLASS AND MECHANISM: Bupropion is an antidepressant
medication that affects chemicals within the brain that
nerves use to send messages to each other. These chemical
messengers are called neurotransmitters. The neurotransmitters
that are released by nerves are taken up again by the
nerves that release them for reuse. (This is referred
to as reuptake.) Many experts believe that depression
is caused by an imbalance among the amounts of neurotransmitters
that are released. Bupropion is unrelated to other antidepressants.
It works by inhibiting the reuptake of dopamine, serotonin,
and norepinephrine, an action which results in more dopamine,
serotonin, and norepinephrine to transmit messages to
other nerves. Bupropion is unique in that its major effect
is on dopamine, an effect which is not shared by the selective
serotonin reuptake inhibitors or SSRIs (e.g. paroxetine,
Paxil; fluoxetine, Prozac; sertraline, Zoloft) or the
tricyclic antidepressants or TCAs (e.g. amitriptyline,
Elavil; imipramine, Tofranil; desipramine, Norpramin).
PRESCRIPTION: yes
GENERIC AVAILABLE: no
PREPARATIONS: Wellbutrin, round tablets: 75 mg (orange),
100mg (red). Zyban, round tablets: 100 mg (blue), 150
mg (purple). Wellbutrin SR, round tablets: 100 mg (blue),
150 mg (purple). Wellbutrin XL, tablets: 150 and 300
mg.
STORAGE: Tablets should be kept at room temperature,
15- 25＜C (59-77＜F).
PRESCRIBED FOR: Wellbutrin, Wellbutrin SR, and Wellbutrin
XL are used for the management of depression. Zyban
has been approved as an aid to patients who want to
quit smoking.
DOSING: Bupropion usually is given in two or three
daily doses. When used for smoking cessation, bupropion
usually is started as 150 mg once daily for three days,
and then the dose is increased if the patient tolerates
the starting dose. Smoking is discontinued two weeks
after starting bupropion therapy. Wellbutrin SR is given
as two daily doses. Wellbutrin XL is given as one dose
daily.
DRUG INTERACTIONS: Although no systematic studies have
been done to assess the potential of bupropion to interact
with other drugs, bupropion should be used cautiously
in patients receiving drugs that reduce the threshold
for seizures. Such drugs include prochlorperazine (Compazine),
chlorpromazine (Thorazine), and other antipsychotic
medications of the phenothiazine class. Additionally,
persons who are withdrawing from benzodiazepines (e.g.
diazepam, Valium; alprazolam, Xanax) are at increased
risk for seizures.
PREGNANCY: Although there are no adequate studies of
bupropion in pregnant women, studies in pregnant animals
using doses much higher than those used in humans, have
demonstrated that bupropion is safe. Bupropion, therefore,
can be used in pregnancy if the physician feels that
it is necessary.
NURSING MOTHERS: It is not known if bupropion is secreted
in breast milk.
SIDE EFFECTS: The most commonly noted side effects
associated with bupropion are agitation, dry mouth,
insomnia, headache, nausea, constipation, and tremor.
In some people, the agitation or insomnia is most marked
shortly after starting therapy. Some patients may experience
weight loss. Uncommonly, patients may experience manic
episodes or hallucinations. Four of every 1000 persons
who receive bupropion in doses less than 450 mg/day
experience seizures. When doses exceed 450 mg/day, the
risk increases ten-fold. Other risk factors for seizures
include past injury to the head and medications which
can lower the threshold for seizures. (See drug interactions.)
"If antidepressants are discontinued abruptly,
symptoms may occur such as dizziness, headache, nausea,
changes in mood, or changes in the sense of smell, taste,
etc. (Such symptoms even may occur when even a few doses
of antidepressant are missed.) Therefore, it is recommended
that the dose of antidepressant be reduced gradually
when therapy is discontinued."
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