“I was at my arthritis group yesterday,” she says, “and one of the women there said that she had got some stronger co-dydramol, which had really helped her. Can I have the same?” Parveen glances down and sees that Linda’s script simply says: ‘Co-dydramol tablets, two to be taken four times a day as required for pain x 100 tablets’.
While co-dydramol has been around for many years, the ratio has always been fixed at 50:1 (paracetamol 500mg plus dihydrocodeine 10mg), and this is what the British Pharmacopoeia defines as “co-dydramol tablets”.
However, in recent months, marketing authorisations have been granted to formulations containing 20mg and 30mg dihydrocodeine in addition to 500mg paracetamol. Linda’s friend has presumably started taking one of these.
This move to a range of co-dydramol products has led to the UK drug regulator, the Medicines and Healthcare products Regulatory Agency (MHRA), advising healthcare professionals to specify the strength of the intended formulation when prescribing. This is to minimise the risk of dispensing errors and the chance of an accidental opioid overdose. The packaging for the higher strength co-dydramol products has been designed so the difference is obvious.
In this situation, Parveen should contact the prescriber to clarify the strength, but the chances are it will be the 10mg/500mg formulation as this is what Linda has had in the past. It would be sensible for Parveen to highlight the MHRA guidance to the GP practice.
It is debatable whether an opioid is the best choice for a patient like Linda, who requires long-term pain management. In ‘Opioids aware’, a resource developed for patients and health professionals, the Faculty of Pain Medicine states that opioids are “very good analgesics for acute pain and for pain at the end of life but there is little evidence that they are helpful for long-term pain”. However, it does say that a small proportion of people may achieve good long-term analgesia if the dose is low and use intermittent.
The side-effects of opioids are well documented, but one that has risen to prominence recently is the effect on driving. This is due to the introduction of a new law, which makes it an offence to have any of a range of specified drugs – including opioids and benzodiazepines – at a level higher than that stipulated, regardless of whether driving is impaired or not, although there is provision for a “medical defence” under certain circumstances. This is particularly pertinent as higher strength co-dydramol enters the market.
Have a look at the FPM Opioids aware resource from the Faculty of Pain Medicine.