Pharmacy Author:
Omudhome Ogbru, PharmD
Pharmacy and Medical Editor:
Jay W. Marks, MD
GENERIC NAME: bupropion
BRAND NAME: Wellbutrin, Wellbutrin SR, Wellbutrin XL, Zyban
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. Many experts
believe that depression is caused by an imbalance among the amounts of
neurotransmitters that are released. Nerves, in a process referred to as
reuptake, may recycle released neurotransmitters. Bupropion works by inhibiting
the reuptake of dopamine, serotonin, and norepinephrine; an action that results
in more dopamine, serotonin, and norepinephrine to transmit messages to other
nerves. Bupropion is unique and unlike other antidepressants in that its major
effect is on dopamine, an effect that is not shared by the selective serotonin
reuptake inhibitors or SSRIs [for example,
paroxetine (Paxil), fluoxetine
(Prozac), sertraline (Zoloft)] or the tricyclic antidepressants or TCAs [for example,
amitriptyline (Elavil), imipramine (Tofranil), desipramine (Norpramin)]. The FDA
approved bupropion in December 1985.
PRESCRIPTION: Yes
GENERIC AVAILABLE: Yes
PREPARATIONS: Tablets: 75, 100, and 150 mg. Sustained Release tablets:
100, 150, and 200 mg. Extended Release tablets: 150 and 300 mg.
STORAGE: Tablets should be kept at room temperature, 15-25°C
(59-77°F).
PRESCRIBED FOR: Bupropion is used for the management of
major
depression and seasonal affective disorder (depression that occurs primarily
during the fall and winter). It is also prescribed for smoking cessation.
DOSING: Bupropion usually is given in one, two or three daily doses.
For immediate-release tablets, no single dose should exceed 150 mg and each dose
should be separated by 6 hours.
For depression the recommended dose of
immediate-release tablets is 100 mg 3 times daily (300 mg/day); maximum dose is
450 mg daily. The initial dose is 100 mg twice daily. The dose may be increased
to 100 mg 3 times daily after three days.
The initial dose of sustained-release
tablets is 150 mg daily; target dose is 150 mg twice daily; maximum dose is 200
mg twice daily.
The initial dose of extended-release tablets is 150 mg daily;
target dose is 300 mg daily; maximum dose is 450 mg daily. Extended release
tablets are administered once daily.
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: 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
[for example, diazepam (Valium), alprazolam
(Xanax)]
are at increased risk for seizures.
Carbamazepine (Tegretol) may reduce the effect of bupropion by reducing the blood
concentration of bupropion. Monamine oxidase inhibitors should not be combined
with bupropion because of the risk of severe reactions. At least 14 days should
elapse between discontinuation of an MAOI and initiation of bupropion. Bupropion
may affect the action of warfarin
(Coumadin).
PREGNANCY: There are no adequate studies of bupropion in
pregnant
women. In one study, there was no difference between bupropion and other
antidepressants in the occurrence of birth defects. Bupropion should only be
used in pregnancy if the benefit outweighs the potential risk.
NURSING MOTHERS: Bupropion is secreted in
breast milk.
SIDE EFFECTS: The most common 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.)
Antidepressants increased the risk of
suicidal thinking and behavior
(suicidality) in short-term studies in
children and
adolescents with depression
and other psychiatric disorders. Anyone considering the use of bupropion or any
other antidepressant in a child or adolescent must balance this risk with the
clinical need. Patients who are started on therapy should be closely observed
for clinical worsening, suicidality, or unusual changes in behavior.
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Back to Medications IndexLast Editorial Review: 11/19/2007
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