Pharmacist advice needed in the use of MR paracetamol

The Therapeutic Goods Administration (TGA) has made an interim decision to upschedule modified release (MR) paracetamol tablets from 1 October 2019 due to safety concerns.

The medicine will change from Schedule 2 (Pharmacy Medicine) to Schedule 3 (Pharmacist Only) in modified release tablets or capsules containing 665 mg or less paracetamol. The announcement follows a submission made to the TGA by PSA in support of reclassification in March 2019.

The Advisory Committee on Medicines Scheduling gave numerous reasons for the decision, including:

• the complex and unpredictable pharmacokinetic profile of MR paracetamol following an overdose therefore the severe consequences of overdose are more likely
• the evidence that the increased risk associated with MR paracetamol use, is linked to unpredictable levels and duration of paracetamol in the blood following an overdose with MR paracetamol
• concerns regarding the risk of overdose outweigh the arguments to retain the Schedule 2 entry in some of the public submissions
• MR paracetamol is substantially safe with pharmacist advice as there is the potential for harm if it is used inappropriately
• there is insufficient evidence to show that overdose treatment protocols sufficiently mitigate the risks associated with MR paracetamol use in Australia
• the large pack size increases the risks associated with overdose with MR paracetamol.¹

This decision follows a trend of suspension of MR paracetamol in Europe and the decision to reschedule MR paracetamol in New Zealand.

The TGA said that the medicine is ‘substantially safe’ when coupled with pharmacist advice and an S3 classification. The rescheduling will ensure additional pharmacist supervision while still allowing for public access. The TGA stated the upscheduling of MR paracetamol may impact unintentional overdose through consumer education about the specific indications of the medicine and the difference in dosage in comparison to immediate release paracetamol. Intentional overdose may also be reduced due to increased pharmacist monitoring of sales and the decision not to supply the medicine to consumers they believe to be at risk of inappropriate use.¹

Overdose with paracetamol is common in Australia and other countries, whether intentional or accidental.¹ In 2016 around 10% of paracetamol overdoses reported to the NSW Poison Information Centre (PIC) involved MR paracetamol.³

Overdose is likely due to confusion about the difference in dose between MR and immediate release paracetamol with the maximum dose being 6 tablets per day for the MR formulation rather than 8 tablets per day for immediate release paracetamol.¹

PSA recommendations

In their submission supporting the reclassification, PSA stated that the availability of MR in pack sizes of 96 within an S2 classification ‘poses an unacceptable risk to the Australian population’ and suggested retaining smaller pack sizes within the S2 classification. However, they noted that smaller pack sizes may pose both an inconvenience and increased cost to those who take MR paracetamol for the relief of persistent pain associated with conditions such as osteoarthritis.²

PSA has also emphasised the risk of the availability of paracetamol products in non-pharmacy outlets due to the high rates of use and the potential for harm. The risks are further compounded through the availability of paracetamol in different dosage forms and types of formulation, in different combination products and for different indications, meaning professional medical advice is essential.

A change to pharmacist workload will likely occur as a result of the upscheduling, particularly at the outset, as pharmacists will need to explain the changes to unaware consumers, carers and patients that use the medicine regularly. According to PSA, the impact will be particularly felt in Queensland, due to additional labelling requirements.²

Pharmacist inventory management will also likely be impacted. Pharmacist feedback has indicated that the use of MR paracetamol is substantially greater than immediate release paracetamol (estimated proportions range between 50/50 and 90/10 for modified and immediate release paracetamol respectively). There are 26 MR paracetamol products currently on the Australian Register of Therapeutic Goods, with individual pharmacist stocks taking demographic and consumer needs into account.

PSA noted the need for clear and consistent messaging to patients in order to minimise any confusion or concern, or any impact of long-term therapy. Long-term patient use of MR paracetamol is often based on medical practitioner advice. Therefore, communication with prescribers will also be necessary to ensure they are aware of changes impacting on patients.²

Pharmacists’ role in advising on the safe use of MR paracetamol products

Pharmacists can help minimise the risk of paracetamol overdose by advising patients about the difference between immediate and modified release formulations, their relevant maximum daily doses, and advising against taking different paracetamol containing products concurrently. Pharmacists can refer to the upcoming CPD article in the July issue of Australian Pharmacist, ‘Topical and OTC management of osteoarthritis’, for more information about assisting patients in the management of chronic pain.

References

1. Therapeutic Goods Administration. Interim decision in relation to paracetamol (modified release). June 2019. At: https://www.tga.gov.au/book-page/15-interim-decision-relation-paracetamol-modified-release
2. Pharmaceutical Society of Australia. Consultation: Referral of proposed amendment to the current Poisons Standard to the meeting of the ACMS, March 2019. At: https://www.tga.gov.au/sites/default/files/public-submissions-scheduling-matters-referred-acms-26-accs-24-and-joint-acms-accs-21-meetings-held-march-2019-psa-02.pdf
3. Chiew A. Questions to the Poison Centres in Australia. Sydney: NSW PIC; 2017 (TRIM D1810783417).