It would be fair to say that eyes are generally not my thing. Watching clamped eyes being operated on makes me squeamish and removing corneal foreign bodies with the help of a 21 gauge needle and a slit lamp was never my most favoured activity in A&E. And as a GP, assessment and management of eye problems remains an area with ‘room for improvement’! However, I thought I was pretty much OK with conjunctivitis. Or that was the case until this week, when information filtered into my sphere, culminating in an alert from my local medicines management team saying that chloramphenicol eye drops are now contra-indicated in children under 2 years old. Eh?
So what on earth is this all about? Well, it’s all about boron, you see. I thought boron was a pretty inert substance, but apparently there have been concerns that boron may impair fertility if given above certain levels. It is used as a buffer agent in chloramphenicol eye drops and that is why we’re run into problems. Back in 2017 this was addressed by the EMA which made recommendations on thresholds of boron that were acceptable in medicines, and that for children under 2 years old the maximum exposure should be 1mg/day.
As discussed in a very helpful DTB editorial this month this has all of a sudden got significant implications for us in General Practice, as the majority of chloramphenicol eye drop products are now not licensed for children under 2. Given that there has been no official communication from the MHRA, this has caught many of us on the hop, with the concern that the first some of us may hear about this is when a prescription is challenged at the dispensing stage.
So what are the risks? The Royal College of Ophthalmologists have posted a useful safety alert putting this in context. It states that ‘Chloramphenicol eye preparations have been widely used in children of all ages for many years with no documented adverse effects on fertility. To our knowledge there is no new scientific data from human studies to support this change to the product license’. They go on to state that if given at a standard dose of 1 drop QDS the amount of boron absorbed will still be well below the 1mg/day threshold.
Okay, so why don’t we just prescribe something else? And that, as discussed in the DTB and by the RCOphth, is the snag. We don’t really have any other suitable products. Fusidic acid has a much narrower spectrum of activity and may not give suitable cover (and is horribly expensive at £35/tube, making it black listed on many formularies). Quinolone and cephalosporin products obviously have real risks of driving resistance, and are specifically not recommended by the RCOphth for bacterial conjunctivitis as they should be reserved for severe eye disease e.g. keratitis. So that basically leaves us with chloramphenicol eye ointment (which does not contain boron), but trying to apply eye ointment to a wriggling toddler is likely to be well-nigh impossible. So while the the RCOphth state that ‘the benefits of chloramphenicol eyedrops in paediatric ophthalmic practice for appropriate indications and with courses of appropriate duration outweigh the possible risks posed by boron ingestion’, it will be very difficult for us in primary care to prescribe when the SPC for many products now states that ’This medicinal product must not be given to a child less than 2 years old as it contains boron and may impair fertility in the future.’
However, there could be a silver lining here. It is an opportunity for us to remind parents that conjunctivitis is not a serious condition, that it self resolves (whether viral or bacterial) in the majority of cases within 10 days, and indeed the NHS advice is not to see a GP unless conjunctivitis has not resolved by 2 weeks (unless for a child under 1 month old). It’s a reminder that the current first line treatment recommended by NICE/PHE is self care (e.g. cotton wool and cooled boiled water) and that exclusion from child care settings is not needed. And if time and self care really don’t sort the problem out, it appears a ‘trial by chloramphenicol eye ointment’ for the under 2s is probably all we have to offer - with a ‘good luck’ to the parents.