Zybansum

MESSAGE FROM PROFESSOR A BRECKENRIDGE, CHAIRMAN OF COMMITTEE ON SAFETY OF MEDICINES ZYBAN- MODIFIED DOSAGE AND SAFETY PRECAUTIONS I am writing to advise you of a modified dosage schedule and new safety precautions for Zyban (bupropion /amfebutamone), a drug licensed as an aid to smoking cessation in nicotine addicted patients. Since its marketing at least 419,000 patients are estimated to have used Zyban. We have received over 5,000 Yellow Card reports, of which 126 were reports of seizures (in approximately 50% of these the patients had predisposing factors for seizure). 1. To minimise the risk of adverse effects, the Committee on Safety of Medicines has advised that, when starting Zyban the lower 150mg dose should be prescribed for the first six days, only increasing to 150mg twice daily on day 7 (The previous recommendation was to increase the dose on day 4). 2. Zyban is associated with a dose-related risk of seizures. There is also an increased risk of seizures occurring in the presence of factors which lower the seizure threshold. To reduce the risk of seizures, prescribers are advised as follows: - with a current seizure disorder or any history of seizures; - current or previous diagnosis of bulimia or anorexia nervosa; - with a known central nervous system (CNS) tumour; - experiencing abrupt withdrawal from alcohol or benzodiazepines. ii) Zyban must not be prescribed in patients with other risk factors for seizures unless there is compelling clinical justification for which the potential benefit of smoking cessation outweighs the increased risk of seizure. In such patients a lower dose of 150mg daily throughout the entire treatment period should be considered. Such risk factors include: - concomitant administration of any drug known to lower the seizure threshold (e.g. antipsychotics, antidepressants, antimalarials, theophylline, systemic steroids, tramadol, quinolones and sedating antihistamines) - alcohol abuse - history of head trauma - diabetes treated with hypoglycaemics or insulin - use of stimulants or anorectic products Due to its complex pharmacology Zyban has considerable potential for interaction with other medicines. Therefore it is important to be aware of all medicines which patients are taking when considering their suitability for Zyban treatment. Please find attached information on important drugs which may interact with Zyban and an information sheet for patients. Further information on drugs which may interact with Zyban can be found in the Pharmaceutical Journal Vol 266 26 May 2001 No 7149 (www.pharmj.com). Smoking is the single greatest cause of premature death in the UK, and is responsible for 120,000 deaths per year. Zyban is clearly effective as an aid to smoking cessation. Its safety will remain under close review - please report any suspected adverse reactions to Zyban via the Yellow Card Reporting Scheme to the Committee on Safety of Medicines/ Medicines Control Agency. Should you require any further information, please telephone MCA on 020 7273 0000. ZYBAN (AMFEBUTAMONE / BUPROPION HYDROCHLORIDE)
IMPORTANT DRUG INTERACTIONS
Effect of interaction
Suggested management
Drugs that lower seizure
threshold, e.g.:
Antipsychotics*
Must not be administered
Antidepressants*
concomitantly with Zyban
Antimalarials
unless there is a
Tramadol
compelling clinical
Theophylline
justification for which the
Systemic steroids
potential medical benefits
Sedating antihistamines,
of smoking cessation
Quinolones
outweighs the potential
risk of seizure. In such
Other predisposing
patients a maximum dose of
factors for seizure:
150mg of Zyban is
Diabetic patients
recommended throughout
treated with
treatment.
hypoglycamics or insulin
Patients taking
stimulants /anorectic
agents
Drugs metabolised by the
CYP2D6 enzyme, e.g.:
Beta-blocke rs e.g.
metoprolol
Type 1c antiarrhythmics
there may be increased should be considered, e.g. e.g. flecainide,
plasma levels of drugs with narrow therapeutic propafenone
Captopril
Loratadine
Codeine/ dihydrocodeine
/dextropmethorphan
*also metabolised by CYP2D6
is added to Zyban should be initiated at the lower end of the dose range. Drugs which may
inhibit/affect the
metabolism of Zyban
Cimetidine
Sodium valproate
Orphenadrine
Cyclophosphamide
Ifosfamide

Levodopa
Monoamine oxidase
inhibitors
should elapse between discontinuation of irreversible MAOIs and initiation of Zyban. For reversible MAOIs the period depends on the ZYBAN - INFORMATION FOR PATIENTS

As with all medicines Zyban is associated with certain side
effects, these have to be carefully weighed up against the known
health benefits of stopping smoking. Zyban may not be suitable
for all patients who wish to stop smoking. It is extremely
important that you discuss with your doctor, who is familiar with
your medical history, your suitability for Zyban treatment.

If you are going to start taking Zyban:
• Tell your doctor if you have ever had a fit or convulsion or
• Tell your doctor or pharmacist if you are taking any other medicines, either those prescribed by your doctor or those bought without a prescription. • When starting Zyban one tablet to be taken once a day for the first 6 days of your treatment course, then one tablet twice a day for the rest of the treatment course. Do not take more than one tablet at any one time and not more than two tablets in a day. If you are currently taking Zyban:
• If you have started Zyban on the original schedule, increasing
the dose on day 4, and feel well, you should continue. • There are certain medicines and medical conditions where it may be necessary that your dose of Zyban is reduced. Tell your doctor or pharmacist : if you have any of the following medical conditions: - If you have ever had a head injury - If you have diabetes that needs to be treated with insulin if you are t aking any of the following medicines: -Anti-malarial medicines (for example, chloroquine, - Certain antihistamines some of which may be used for sleep problems (for example, Piriton, Dimotane, Nytol or Panadol Night) - Medicines to treat depression or medicines to treat other mental illness (for example clozapine, risperidone, thioridazine or olanzapine) - Theophylline, which is a medicine used to treat chest - Steroids taken as tablets or injections (for example, - Certain antibiotics (for example, ofloxacin, levofloxacin - Tramadol, which is a strong pain killer - Slimming medicines or other stimulant medicines • While you are taking Zyban it is very important to tell your doctor or pharmac ist before you take any new medicines.
Please read the Zyban Patient Information Leaflet carefully.

Source: http://www.ash.org.uk/files/documents/ASH_437.pdf