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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