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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. 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).
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 major depression and seasonal affective disorder (depression that occurs primarily during the fall and winter). 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."
It has been suggested that bupropion and SSRIs may cause depression to worsen and even lead to suicide in a small number of patients. These potential side effects are difficult to evaluate in depressed patients because depression can progress with or without treatment, and suicide is itself a consequence of depression. Moreover, the evidence supporting these potential side effects is weak. Therefore, no conclusions can yet be drawn about the relationship between bupropion and SSRIs and worsening depression and suicide. Until better information is available, patients receiving bupropion or SSRIs should be monitored for worsening depression and suicidal tendencies. | |
