Suspension of sales of dextropropoxyphene-containing products

The Health Sciences Authority (HSA) would like to inform healthcare professionals that the sales of dextropropoxyphene-containing products have been suspended effective from 9 November 2009.

Dextropropoxyphene, a weak synthetic opioid analgesic, was registered by HSA since 1991 for the treatment of mild to moderate pain. It was marketed under two brands namely Dolpoxene® (Singapore Pharmaceutical Pte Ltd) which contains only dextropropoxyphene and Dolpocetmol® (Singapore Pharmaceutical Pte Ltd) which contains a combination of dextropropoxyphene and paracetamol.

HSA's risk-benefit assessment of dextropropoxyphene

HSA has been closely monitoring the safety profile of dextropropoxyphene following withdrawal of dextropropoxyphene-containing products by UK in 20051 and the European Union2 in June 2009. Based on the assessment of the data available to-date, HSA and its Pharmacovigilance Advisory Committee (PVAC) have concluded that the risk of dextropropoxyphene outweighs its benefits in the treatment of mild to moderate pain.

The review took into consideration its limited therapeutic efficacy as compared to commonly used analgesics, the availability of other therapeutic alternatives such as paracetamol, NSAIDs and opioids, the potential risk of fatal overdose associated with dextropropoxyphene as well as the risk-benefit assessments of other regulatory agencies. In addition, it has also been highlighted in several literature articles that norpropoxyphene, the metabolite of dextropropoxyphene, has been associated with cardiac toxicities.3,4

The potential risk of fatal overdose with dextropropoxyphene and cardiac toxicities associated with its metabolite, norpropoxyphene are considered unacceptable in view of dextropropoxyphene's modest efficacy. As such, the importation, sales and marketing of Dolpoxene® and Dolpocetmol® at the wholesale level was suspended with effect from 9 November 2009.

Healthcare professionals are advised not to start new patients on dextropropoxyphene and to consider alternative treatment options for patients currently taking dextropropoxyphene products for pain relief.

References

  1. Press release. MHRA withdraws the pain killer Co-proxamol.
    http://www.mhra.gov.uk/NewsCentre/Pressreleases/CON002065
  2. PRESS RELEASE. EMEA recommends withdrawal of dextropropoxyphene-containing medicines http://www.emea.europa.eu/pdfs/human/press/pr/40106209en.pdf
  3. Chan Gl, Matzke GR. Effects of renal insufficiency on the pharmacokinetics and pharmacodynamics of opioid analgesics. Drug Intell Clin Pharm. 1987; 21:773 – 783
  4. Nagar S, Raffa RB. Looking beyond the administered drug: Metabolites of opioid analgesics. The Journal of Family Practice 2008; Vol 57, No. 6: S25 –S32
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