Medicines management: Why must co-dydramol now be prescribed by strength rather than number of tablets?

With new co-dydramol products now available with a higher strength of opioid analgesic dihydrocodeine, prescribing and dispensing them by strength is vital to ensure patient safety and minimise the risk of accidental opiate overdose, says medicines management expert Matt Griffiths

Co-dydramol is a common analgesic that has been used in healthcare for decades.

It used to be prescribed as one to two tablets, but with new strengths of the drug recently having been given marketing authorisation in the UK, this practice needs to be changed to ensure patient safety is not put at risk.

Co-dydramol, a combination of dihydrocodeine and paracetamol, was previously only available in the ratio 1:50 (co-dydramol 10/500mg). But two other products are now available with a higher strength of dihydrocodeine – co-dydramol 20/500mg and 30/500mg tablets.

Prescribing and dispensing co-dydramol products by strength is therefore vital to ensure patients do not get the wrong dose, and to minimise the risk of accidental opiate overdose.

Prescriptions for co-dydramol should always be written as the dose of dihydrocodeine followed by the dose of paracetamol in each tablet in milligrams (mg).

Risk of errors

So this would be written as 10/500mg, 20/500mg and 30/500mg tablets. The ratio should never be written as 1:50, 2:50 or 3:50.

To differentiate between strengths, manufacturers have altered the packaging for the different co-dydramol products, but ‘lookalike’ and ‘sound alike’ errors can occur, with the risk of errors increasing when there has historically only been one dose of a particular tablet.

All professionals coming into contact with patients taking these medications must be aware of the new doses so that prescribing, dispensing and administering of the drugs can be done safely. Patients taking co-dydramol should also be informed of the changes so they can be vigilant when the medication is dispensed.

If you are made aware of any errors regarding new or old doses of co-dydramol, ensure they are reported via the Medicines & Healthcare products Regulatory Agency’s yellow card scheme so that errors can be monitored.

Matt Griffiths is visiting professor of prescribing and medicines management at Birmingham City University