Opioid poisoning deaths in New Zealand (2001-2002)

To investigate the rates of opioid deaths in New Zealand relative to the utilisation of opioids.

Deaths from opioid poisonings for New Zealand from 1 January 2001 to 31 December 2002 were identified from chemical injury cases that are routinely collected for surveillance purposes by the Institute of Environmental Science and Research from the Coronial Services Office in Wellington. Prescriptions for medicines containing morphine, methadone, and dextropropoxyphene were identified from the PharmHouse database from 1 January 2001 to 31 December 2002.

There were 92 poisoning deaths involving opioids: morphine in 33, methadone in 31, dextropropoxyphene in 16, and codeine/dihydrocodeine in 12. The rate (95% CI) of deaths per 100,000 prescriptions was 5.94 (4.09 to 8.34) for morphine, 1.34 (0.91 to 1.91) for methadone, and 2.5 (1.45 to 4.12) for dextropropoxyphene. The rate of deaths (95% CI) per 1,000,000 defined daily doses was 0.94 (0.65 to 1.32) for morphine, 0.40 (0.27 to 0.56) for methadone, and 0.14 (0.08 to 0.22) for dextropropoxyphene.

Restrictions in the availability of dextropropoxyphene, and increased monitoring of prescription and dispensing of methadone, should be considered in order to reduce deaths due to opioids in New Zealand.