This is an update to a previous post titled: Nearly a year on, Bupropion is still not available

I was worried the previous post might cause confusion to those who came across it hoping for the return of bupropion. Below, I’ve tried to go into a little detail about the potential reasons for the announced return – but please bear in mind I might have easily misinterpreted certain details, and an announcement from a secondary source does not mean resupply is confirmed. I’ve also given an update on the current availability of bupropion in the UK.

UPDATE: Zyban might be back in stock already, GSK‘s medications out-of-stock page has removed Zyban, and the NCSCT has put a notice up on October 16th saying that Zyban is back in stock and being supplied – check with your local pharmacy to confirm if this is in fact true.

UPDATE #2: GSK‘s medications out-of-stock page now says that Zyban will return in late November 2023

So, a notice popped up about a week ago in the form of an exclusive article by David Lipanovic of the Pharmaceutical Journal. It announced that bupropion will once again be supplied to the UK starting around December 2023.

Why has the resupply been announced?

The Pharmaceutical Journal article explains that the decision to resupply bupropion was a result of “updated guidance from the European Medicines Agency (EMA) on nitrosamine impurities, published in July 2023, which sets out a 1500 nanogram/day limit for acceptable daily intake of n-nitroso-bupropion.

Looking a bit closer at the updated guidance, it seems like the EMA categorised medications according to a potency score, ranging from 1 – 5 (1 is the highest potency, 5 is the lowest potency). They name this the “Carcinogenic Potency Categorization Approach” which is based on “structure-activity relationship concepts” described by recent scientific research on N-nitrosamine compounds (see references included in the EMA document linked above)

Much of the process they describe has gone well over my head – I was never very good at chemistry! So either please find your nearest chemist (the scientist not the building) for a better explanation, or if you are a chemist, please do contact me telling me where I’ve gone wrong!

From my sketchy understanding, they seem to suggest that N-nitrosamine compounds that are more favourable to the inclusion of a hydroxyl group (-OH) are more likely to be carcinogenic. Therefore, they have devised a decision tree to assess the chemical structure of each medication with an N-nitrosamine impurity. The result of the decision tree gives the classification and helps to indicate the acceptable limit of N-nitrosamine impurities for each medication (in nanograms per day). I should note that the EMA report does state that these classifications are conservative.

The bupropion impurity structure (n-nitroso-bupropion) is given a “5” classification (meaning very low carcinogenic potency) with an acceptable limit of 1500 ng/day. This may suggest why GSK has announced the proposed reintroduction of Bupropion on a relatively short timescale (upscaling production takes a lot longer than most assume). My hunch is they have made no change to the production process at all. I am guessing the amount of n-nitroso-bupropion impurities they originally found was much less than 1500 ng per day.

Compare this to Champix (Varenicline), which has a much lower daily allowance of only 37 ng/day. This may suggest why it has been out of production for much longer than bupropion, and from my current knowledge, why there hasn’t been a similar announcement of resupply.

Updates on the current availability of Bupropion

  • A Question to the Department of Health and Social Care from the 19th of July has revealed that there is a suggestion that an unlicensed supply of bupropion has been sourced for UK residents.
  • Two suppliers are mentioned on the NHS medication supplier info website
  • A Reddit comment has suggested that Hive Pharmacy have an unlicensed supply of Bupropion and are accepting NHS prescriptions
  • I have followed this up and they have told me that they do in fact have a supply of imported (therefore unlicensed) Bupropion MR 150 mg tablets.
  • Hive Pharmacy advise that you get in contact with them via WhatsApp (see bottom of this page) to confirm the availability of Zyban and for instructions on the prescription process