Approval of cytisine for smoking cessation takes step forward

Cytisine could soon be made available to GPs to prescribe for smoking cessation, as the Advisory Committee on Medicines Scheduling (ACMS) undergoes public consultation to amend the current Poisons Standard.
 
While the treatment has never been made accessible in Australia, the Therapeutic Goods Administration (TGA) states ‘there are reports of unregistered cytisine lozenges already available to consumers’.
 
In a new submission to the ACMS, released on Tuesday, RACGP President Dr Nicole Higgins says the college welcomes the move to make cytisine available.
 
‘There is moderately certain evidence supporting the efficacy of cytisine for smoking cessation and while it can cause some mild gastrointestinal symptoms, it has a very low risk of serious adverse effects,’ Dr Higgins writes.
 
Cytisine is a partial nicotine receptor agonist and belongs to the same class of medicine as varenicline.
 
The plant-derived smoking cessation aid has been around for decades and is available overseas.
 
In Australia, the TGA has made an interim decision to create new entries for cytisine in Schedules 3 and 4.
 
Although the TGA says ‘cytisine use is associated with more adverse events than other nicotine replacement therapies’, its report says it is satisfied that ‘pharmacist oversight can sufficiently mitigate these risks’.
 
But Dr Higgins says the RACGP will not go as far as supporting pharmacy prescribing.
 
‘Enabling access to this low cost first-line medicine must be balanced by mitigating the risks of possible contraindications, drug interactions and fragmented care,’ she said.
 
Currently the proposed amendment is only for smoking, with Dr Higgins saying the RACGP would recommend it be expanded to include nicotine dependence and vaping.
 
‘There is a dearth of strong evidence supporting any pharmacological approaches to managing vaping cessation and the RACGP supports the cautious prescribing of cytisine to assist with vaping cessation, in conjunction with behavioural support,’ she said.
 
A 2023 study found cytisine was more effective than placebo and nicotine replacement therapy, but not more than varenicline, however, researchers noted less adverse events compared to varenicline.
 
Common adverse effects of cytisine are gastrointestinal issues, dry mouth, dizziness and increased appetite, but the TGA notes ‘some of these adverse events may be attributable to nicotine withdrawal’.
 
‘Cytisine may also interact with some commonly used medicines such as streptomycin, theophylline, clozapine, ropinirole, and hormonal contraceptive pills, and reduce their effectiveness,’ says the TGA.
 
Chair of the RACGP’s smoking cessation guidelines Expert Advisory Group, Professor Nick Zwar, supports this stance.
 
‘There’s not a lot of evidence yet on what forms of treatment can help support vaping cessation, but there have been a small number of trials of cytosine, with a small number of patients, that have shown some favourable results,’ he told newsGP.
 
Professor Zwar says GPs will need to do some research into the drug before it is greenlit.
 
‘One of the barriers to use of cytisine has been a complex dosage regime where someone needed to take a tablet every two hours,’ he said.
 
‘GPs will have to learn about it, which is yet another task in our busy lives, but another medicine that can help us is welcome.’
 
The TGA has earmarked an implementation date of 1 October to ‘avoid any unnecessary delay to industry’.
 
Dr Higgins said the RACGP is in the midst of updating its smoking cessation guidelines, which will now be revised to include cytisine for nicotine dependence. 
 
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