Bupropion chemical structure
Find information on thousands of medical conditions and prescription drugs.

Zyban

Bupropion (amfebutamone) is an antidepressant of the amino ketone class, chemically unrelated to tricyclics or selective serotonin reuptake inhibitors (SSRIs). It is similar in structure to the stimulant cathinone, and to phenethylamines in general. It is a chemical derivative of diethylpropion, an amphetamine-like substance used as an anorectic. Bupropion is both a dopamine reuptake inhibitor and a norepinephrine reuptake inhibitor. more...

Home
Diseases
Medicines
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
Zafirlukast
Zagam
Zalcitabine
Zaleplon
Zanaflex
Zanamivir
Zantac
Zarontin
Zelnorm
Zerit
Zestoretic
Zestril
Zetia
Zevalin
Ziagen
Zidovudine
Zileuton
Ziprasidone
Zithromax
Zocor
Zofran
Zoladex
Zoledronic acid
Zolmitriptan
Zoloft
Zolpidem
Zometa
Zomig
Zonegran
Zonisamide
Zopiclone
Zosyn
Zovia
Zovirax
Zyban
Zymar
Zyprexa
Zyrtec
Zyvox

History

Bupropion was first synthesized by Burroughs Research in 1966, and patented by Burroughs-Wellcome (later Glaxo-Wellcome, and, as of 2000, GlaxoSmithKline) in 1974. It was approved by the FDA in 1985 and marketed under the name Wellbutrin as an antidepressant, but clinical trials indicated that incidence of seizure was two to four times greater than other antidepressants and the drug was quickly pulled from the market. It was subsequently discovered that reducing the dose by about half greatly reduced the risk of seizures. Glaxo then developed a sustained-release (SR) version of Wellbutrin which releases bupropion hydrochloride at a slower rate. The SR formulation is taken twice a day, in order to further decrease the possibility of adverse side effects and seizures. It is also available in generic form (Bupropion SR). Extended Release bupropion, Wellbutrin XL, is the most recent formulation of bupropion and is taken orally once a day. Because of this altered mechanism of delivery and reduced dosing, incidence of seizures with bupropion is comparable to, and in some cases, lower than that of other antidepressants.

In 1997, bupropion HCl was approved by the FDA for use as a smoking cessation aid. Glaxo subsequently marketed the drug under the name Zyban to help people stop smoking tobacco by reducing the severity of craving and addiction/withdrawal symptoms. It can be used in combination with nicotine replacement therapies. Bupropion treatment course lasts for seven to twelve weeks, with the patient halting the use of tobacco around ten days into the course.

Bupropion is also being investigated as a weight loss drug.

Mode of action

Bupropion is a selective catecholamine (norepinephrine and dopamine) reuptake inhibitor. It has only a small effect on serotonin reuptake. It does not inhibit MAO. The actual mechanism behind bupropion's action is not known, but it is thought to be due to the effects on dopaminergic and noradrenergic mechanisms.

Pharmacokinetics

Bupropion is metabolised in the liver. It has at least three active metabolites: hydroxybupropion, threohydrobupropion and erythrohydrobupropion. These active metabolites are further metabolised to inactive metabolites and eliminated through excretion into the urine. The half-life of bupropion is 20 hours as is hydroxybupropion's. Threohydrobupropion's half-life is 37 hours and erythrohydrobupropion's 33 hours.

Chronic hepatotoxicity in animals

In rats receiving large doses of bupropion chronically, there was an increase in incidence of hepatic hyperplastic nodules and hepatocellular hypertrophy. In dogs receiving large doses of bupropion chronically, various histologic changes were seen in the liver, and laboratory tests suggesting mild hepatocellular injury were noted.

Read more at Wikipedia.org


[List your site here Free!]


Study examines Zyban's use in smoking cessation, weight loss - Brief Article
From Drug Store News, 10/22/01

A Mayo Clinic study suggests prescription drug Zyban (wellbutrin) may help keep ex-smokers off cigarettes and help them maintain or even lose weight. More than half of the 800 smokers studied stopped smoking after seven weeks on the drug. Half of that group continued taking the drug for a year. At the end of the year, 55 percent of the Zyban group was still smoke-free. Two years later, however, similar numbers of the Zyban and non-Zyban groups had relapsed. Women in both groups gained some weight, but those on Zyban gained less up to two years later.

Zyban maker GlaxoSmithKline funded the study. GSK recently distributed important safety information about Zyban in response to the Canadian Health Department's belief that the drug is linked to 19 deaths in the country. The supplemental information indicates that the drug can cause nausea, headache, seizures and high blood pressure.

COPYRIGHT 2001 Reproduced with permission of the copyright holder. Further reproduction or distribution is prohibited without permission.
COPYRIGHT 2001 Gale Group

Return to Zyban
Home Contact Resources Exchange Links ebay