May 2001 newsletter

Adobe Acrobat version available here

Zyban and diving

There has been recent publicity regarding the use of zyban and the risk of epileptic seizures. Zyban is manufactured by GlaxoSmithKline and was originally developed as an antidepressant (Wellbutrin) but found more commercial success as a drug to aid smoking cessation.

The concern regarding zyban and diving is the dose dependent risk of seizures and the company estimate the absolute risk to be around 1 in 1000 when taking zyban up to 300mg per day. In higher doses (used for the treatment of depression) the risk was increased to 4 per 1000. The risk is significantly higher in patients with histories of head trauma, previous seizures, central nervous system tumours, severe hepatic cirrhosis and medications that lower seizure threshold.

The risk is also higher in the following settings:

• Excessive use of alcohol
• Abrupt withdrawal from alcohol or other sedatives
• Addiction to opiates, cocaine or stimulants Use of over-the-counter stimulants and anorectics
• Diabetics treated with oral hypoglycaemics or insulin
• Medication including antipsychotics, antidepressants, systemic steroids, theophylline, and antimalarial drugs.

Like any medication zyban is associated with side effects, and the incidence of those relevant to diving is as follows:

Recent concerns were highlighted by the death of a 21 year old flight attendant who collapsed and died while taking zyban and chloroquine. The risk of zyban and chloroquine is due to be highlighted by GlaxoSmithKline and they will emphasise that the two drugs are “incompatible”. The UKSDMC advise that divers should not dive while taking zyban. The drug is usually prescribed for a fairly short course to help patients stop smoking, and it should be emphasised that the risk of diving during this short period is grossly excessive. Zyban can be used as ongoing treatment for depression, and such patients should advised against diving for the same reasons. Further drug information is available from the company directly, or via the internet (www.zyban.com) which includes detailed prescription information and more details regarding the frequency of side effects and drug interactions.