Pharmaceutical

Crushing Circadin® MR tablets

Whether or not it’s OK to crush Circadin® MR tablets is a question that keeps coming up over and over again. This is because it’s the only licensed melatonin tablet in the UK, and it’s probably also the cheapest and easiest to for pharmacies to obtain. This is all good. The problem is that it’s not licensed in kids, and a lot of prescriptions for melatonin are for children. Furthermore, Circadin is a modified release tablet, and as we all know, crushing modified release tablets is a Bad Thing because it’s liable to release all the drug (which someone has taken a great deal of trouble to make release slowly) all at once.

People have died from crushed modified release tablets (though not melatonin).(1-3)

However, in the case of Circadin®, the situation is a little less lethal. Melatonin is often used in immediate-release tablets, and lots of patients don’t need the modified release properties. So it doesn’t matter so much – for those patients – if the modified-release properties are destroyed by crushing.

In fact, the manufacturer – on their Circadin® website, in the Q&A section(4) – states:

Crushing a Circadin® tablet will not damage the active ingredient (melatonin). There are no safety concerns with crushing Circadin®, however it will affect prolonged-release properties of the product. The tablet matrix maintains its prolonged-release properties as long as it is ingested as a whole. The prolonged-release properties will be maintained to some extent also if the tablet is halved or divided into 4 quarters. If it is crushed it will release melatonin similarly to an immediate release formulation. According to the SmPC the tablets should be swallowed whole in order to get the full prolonged-release properties.

The information leaflet on the very nice Medicines for Children website(5) also states:

Modified-release tablets (Circadin) should be swallowed whole unless your doctor or pharmacist has told you otherwise. Your child should not chew the tablet. Sometimes, your doctor or pharmacist may have told you to crush it – this will make it act faster, but the effect will not last as long.

However, anyone advising patients to do this should bear in mind that crushing tablets generally renders them off-licence (although Circadin use is off-licence in children anyway). The GMC has guidance regarding off-licence prescribing here.

So, in short, Circadin® tablets may be crushed if:

  • The patient cannot, or will not, swallow the tablets whole AND
  • The modified release characteristics are not required (e.g. in a patient who would otherwise be prescribed a non-modified release formulation, such as melatonin liquid.

If a patient requires a modified-release formulation, but cannot swallow Circadin® tablets whole, then cutting them in half or into quarters (preferably half rather than quarters if possible) will preserve the matrix formulation which provides the modified-release characteristics to some extent.

Health Warning

If patients (or carers) are advised to crush or divide Circadin® tablets, they should be counselled carefully to ensure that they understand that this recommendation applies only to Circadin® tablets, as it is known that causing the immediate release of all of the drug in the tablet is not harmful in this case.

This advice does not apply to other modified-release products; serious adverse effects have been reported when modified-release formulations have been crushed without first establishing the safety of doing so.

References

  1. ‘I will always blame myself’. BBC [Internet]. 2006 Oct 26 [cited 2015 Aug 5]; Available from: http://news.bbc.co.uk/1/hi/health/6085292.stm
  2. Schier JG, Howland MA, Hoffman RS, Nelson LS. Fatality from administration of labetalol and crushed extended-release nifedipine. Ann Pharmacother. 2003 Oct;37(10):1420–3.
  3. Cornish P. ‘Avoid the crush’: hazards of medication administration in patients with dysphagia or a feeding tube. CMAJ Can Med Assoc J. 2005 Mar 29;172(7):871–2.
  4. Q&A | Circadin® [Internet]. [cited 2015 Nov 13]. Available from: http://www.circadin.com/about-circadin/qa/
  5. Melatonin for sleep disorders | Medicines for Children [Internet]. [cited 2015 Nov 13]. Available from: http://www.medicinesforchildren.org.uk/melatonin-sleep-disorders