A new oral opioid, oxycodone, has been launched by Napp Pharmaceuticals. The drug has, up to now, only been available in a suppository formulation.
Oral oxycodone is being marketed as conventional release capsules and liquid (Oxynorm) and as modified release tablets (Oxycontin), with licences to treat moderate to severe pain in patients with cancer and postoperative pain (see p230).
Napp suggests that the new drug has advantages over morphine. Dr Chris MacDonald (director of medical affairs) said on February 1 that oxycodone had more predictable pharmacokinetics than morphine, making it easier to optimise pain control, and was better tolerated. There was evidence of fewer hallucinations and less itching than with morphine.
Dr MacDonald said that another benefit of oxycodone was that it avoided the stigma attached to use of morphine. There was still a reluctance of doctors to prescribe morphine in palliative care and a reluctance of patients to take the drug. Patients' concerns included fears of addiction and anxiety that use of morphine meant that death was imminent. He believed that patients would be happier to take oxycodone which did not have these "connotations".
Dr Mhoira Leng (consultant in palliative medicine, Aberdeen Royal hospitals NHS trust), who has experience of prescribing oral oxycodone, says that the new drug might have theoretical advantages over morphine but that clinical experience is needed to see where it will fit into practice. Speaking to The Journal on February 1, Dr Leng suggested that, for now, oxycodone was likely to be used as a second line agent when a strong opioid was needed and morphine had caused side effects.
She said that oxycodone had attractive pharmacokinetic features, associated with a high oral bioavailability and lack of significant metabolites. Experience in the US suggested that it was well tolerated. However, if morphine was prescribed well, its side effects could be managed most of the time, although some patients could not tolerate the dose required for adequate analgesia.
Dr Leng said that she would welcome the future addition of a parenteral formulation of oxycodone. This would be important for patients who became unable to swallow.
In the US, oxycodone came to prominence in the 1980s with the use of combined formulations with aspirin or paracetamol. These are used in the same way as codydramol and coproxamol in the UK. The modified release formulation was developed by Purdue, a Napp associate company, and launched in the US in 1996.