The Pharmaceutical Journal Vol 267 No 7155 p15-16
July 7, 2001

  Pharmacy technicians
  Education
  Amfebutamone
  Self-checking
  SGM
  Separate registers
  Primary care pharmacy

Amfebutamone

Interaction information often not available

From Dr I. H. Stockley, FRPharmS

Alison Barnet is highly critical (PJ, 23 June, p852) of GlaxoSmithKline’s failure to come up with positive answers to her questions about whether specific drugs interact with amfebutamone (Zyban), but a likely reason is that hard data are largely lacking. She mentions the list which the West Midlands Centre for Adverse Drug Reactions recently published (PJ, 26 May, p721) but it needs to be pointed out that this list is mostly speculative. It is certainly impressive and long (almost 200 drugs or drug groups), but the authors clearly state that it contains “potential” interactions, that it is “provisional”, and that it contains drugs which “might” interact with Zyban. So there is a very large question mark hanging over the whole thing.

Zyban is in spotlight at the moment because of its use in helping people to stop smoking, but it is not a new drug. It was originally introduced in 1989 as an antidepressant which was later found to have a new and useful application. But it is a well-tried drug in another context. About 22 million patients are estimated to have taken it worldwide and millions of them will have been taking other drugs at the same time. Even so there is virtually nothing in the literature to suggest that adverse interactions are a major problem; 12 years is usually long enough for the most important interactions to surface.

I sympathise with Mrs Barnet’s wish to be supplied with answers about interactions with Zyban, but if definitive information from clinical studies simply is not available, then her questions cannot be firmly answered. It obviously leaves things up in the air to be told “we don’t actually know”, but sometimes it is the only truthful thing to say, which is the gist of what Dr Yvonne Greenstreet of GSK wrote in response to Mrs Barnet’s letter.

Ivan Stockley
Loughborough,
Leicestershire

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