| Brand Name |
Zyban |
| Generic Name |
Bupropion Hydrochloride - Sustained
Release Tablets |
| Company |
Glaxo-Wellcome |
| Indication(s) |
An aid to smoking cessation
treatment. |
| Contraindications |
Patients treated with Wellbutrin or any other
medications that contain bupropion, in patients with a current or prior diagnosis
of bulimia or anorexia nervosa, in patients taking mono-amine oxidase inhibitors
(MAOIs) and in patients who have shown a hypersensitivity to bupropion. Patients
who have taken MAO inhibitors must wait at least 14 days between the
discontinuation of MAO inhibitor therapy and the commencement of Zyban
therapy. |
| Mechanism of Action |
Inhibitor of the neuronal uptake
of norepinephrine, serotonin and dopamine. |
| Dosage Form(s) |
150 mg tablets |
| Administration |
The recommended and maximum dose of Zyban
is 300 mg/day given as 150 mg, twice daily. Dosing should begin at 150 mg/day
for the first three days followed by an increase to the usual dose of 300
mg/day. Treatment should be initiated while the patient is still smoking
and a target date for smoking cessation should be within the first two weeks
of Zyban treatment. Zyban therapy should continue for 7 to 12 weeks, depending
on the effect of the therapy. If the patient has not reduced smoking by the
seventh week of Zyban therapy, it is unlikely that he/she will quit during
that attempt and Zyban therapy should be discontinued. |
Common Side Effects
Adverse events were compiled from two clinical studies, a
dose-response trial and a comparator trial. Adverse events noted in the
dose-response trial occurring at a frequency of greater than 2 % and greater
in the Zyban group than in the Placebo group are listed in the following
table:
| Adverse Event |
Incidence Rate (%) |
Zyban
100 - 300 mg/day
(n=461) |
Placebo
(n=150) |
Dry mouth
Insomnia
Dizziness
Arthralgia
Pruritis
Rash |
11
31
8
4
3
3 |
5
21
7
3
<1
<1 |
Adverse events noted in the comparator trial occurring at
a frequency of greater than 2 % and greater in the Zyban group than in the
Placebo group are listed in the following table:
Adverse
Event |
Adverse
Event Incidence in Comparative Trials (%) |
Zyban
300 mg/day
(n=243) |
Nicotine Transdermal System
(NTS)
21 mg/day
(n=243) |
Zyban and NTS
(n=244) |
Placebo
(n=159) |
Abdominal Pain
Nausea
Dry mouth
Constipation
Diarrhea
Anorexia
Myalgia
Arthralgia
Insomnia
Dream abnormality
Anxiety
Disturbed concentration
Dizziness
Nervousness
Rhinitis
Increased cough
Pharygitis
Application site reaction
Rash
Pruritis
Taste perversion |
3
9
10
8
4
3
4
5
40
5
8
9
10
4
12
3
3
11
4
3
3 |
4
7
4
4
4
1
3
3
28
18
6
3
2
<1
11
5
2
17
3
1
1 |
1
11
9
9
3
5
5
3
45
13
9
9
8
2
9
<1
3
15
3
5
3 |
1
4
4
3
1
1
3
2
18
3
6
4
6
2
8
1
0
7
2
1
2 |
The second series of clinical trials examined the adverse
events associated with Zofran treatment for the prevention of post-operative
nausea and vomiting. These were placebo controlled trials:
Drug Interactions
In vitro studies indicate that bupropion is metabolized by
the cytochrome P-450 2B6 enzyme. Therefore, there is potential for a drug
interaction between Zyban and drugs that effect CYP2B6 such as orphenadrine
and cyclophosphamide. Certain drugs such as carbamazepine, phenobarbitol,
and phenytoin may induce the metabolism of bupropion while others such as
cimetidine may inhibit its metabolism. No formal studies have been conducted
in humans to assess the effects of drug interactions.
Bupropion is the same active ingredient found in the
anti-depressant Wellbutrin. Therefore, patient's being treated for depression
with Wellbutrin should not take Zyban as it would increase the plasma levels
of bupropion.
Two clinical trials were carried out to determine the
effectiveness of Zyban as an aid in smoking cessation. The first trial was
a dose-response trial during which the endpoint was abstinence from week
4 of the study.
| Abstinence From
Week 4 through Specified Week |
Quit
Rates by Treatment Groups (%) |
Placebo
(n=151) |
Zyban
100 mg/day
(n=153) |
Zyban
200 mg/day
(n=153) |
Zyban
300 mg/day
(n=156) |
| Week 7 |
17 |
22 |
27 |
36 |
| Week 12 |
14 |
20 |
20 |
25 |
| Week 26 |
11 |
16 |
18 |
19 |
The second trial was a comparator trial that also measured
abstinence from week 4 of the study.
| Abstinence From
Week 4 through Specified Week |
Quit
Rates by Treatment Groups (%) |
Placebo
(n=160) |
NTS
(n=244) |
Zyban
300 mg/day
(n=153) |
Zyban
300 mg/day and NTS
(n=245) |
| Week 7 |
23 |
36 |
49 |
58 |
| Week 10 |
20 |
32 |
46 |
51 |
| 