10th June 2011, Volume 124 Number 1335

Geoffrey Robinson, Graeme Judson, Richard Loan, Timothy Bevin, Patrick O’Connor

Prescription drug abuse has been a long-standing issue in New Zealand,1 which in the past has been overshadowed by imported heroin, cannabis, and more recently by methamphetamine.

Regarding opioids, New Zealand was placed in an unusual situation 30 years ago when the “Mr Asia” supply ring was contained, and imported heroin became increasingly uncommon and virtually unavailable for “street” supply. In this situation prescription opioids became a prime source, and the misuse of buprenorphine was a notable initial consequence, followed by morphine and methadone.2–4

A number of transient “New Zealand innovations” emerged: firstly the “homebake” phenomenon of producing morphine/heroin from over-the-counter codeine (combination) products,5 secondly the development of oral opium ingestion from poppyseed tea,6 and perhaps, more recently, increasing misuse of codeine itself from prescribed or over-the-counter combination sources.7

However continuing prescription drug abuse is of ongoing concern in New Zealand,8 and also particularly in the United States.9–11

We were prompted to evaluate the pattern of current drug use in patients presenting to our drug clinics, as there has not been a recent survey.

Methodology

This study was restricted to new patients (new episode of care) who presented to three provincial clinics, and who were seen by medical staff, usually in the course of assessment for opioid substitution treatment, but also for withdrawal management.
In the course of taking the drug history, the medical officer completed a form on prescription drug use over the previous 7 days. This included the drug(s), daily dose, route of administration, and source (street or prescription). There was a further section to estimate the total costs of each street-sourced drug for the previous 7 days.
This form did not collect information about alcohol, cannabis or tobacco.
This information was collected from October 2009 until April 2010 on consecutive new patients seen by the medical staff.

Results

There were 37 assessments comprised of 12 from Hawke’s Bay, 15 from Taranaki and 10 from Palmerston North.

There were 26 men and 11 women, with a median age of 34 years (21–56 range).

Drugs

Opioids—10 patients reported using intravenous morphine as their only opioid over the previous week. The mean dose/day was 169 mg (median 105), with a range of 40–600 mg/day.

Another 12 reported using intravenous methadone as their sole opioid over the previous week, at a median dose of 50 mg/day, with a range of 27–70 mg/day.

There were a further 11 patients who reported using a mix of opioids over the previous 7 days. Ten of those reported using morphine, which was combined with methadone in seven. Two morphine users were prescribed Dihydrocodeine tartrate (DHC Continus) at doses of 180 mg and 240 mg daily, and another reported street-sourced DHC Continus at 60 mg/day.

One patient reported using a mixture of morphine, methadone and oxycodone, the latter at a mean dose of 70 mg daily. Two patients reported regular use of codeine at 190 mg/day in addition to morphine or methadone. One patient reported regular use of opium in addition to morphine. No patients reported poppyseed tea or codeine-sourced “homebake” morphine use.

We included 2 subjects who reported using over-the-counter codeine combinations, as codeine can be a prescription drug. The doses of codeine were 260 mg/day and 800 mg/day. One patient reported problematic use of prescribed tramadol.

Stimulants—There was one presentation due to street-sourced methylphenidate.

Hypnosedatives—Seventeen patients reported use of hypnosedatives over the previous week. These were prescribed to five patients, and street-sourced in the remainder. This included a wide range of benzodiazepines, and zopiclone in one case. These drugs were all reported being used at usual therapeutic dosages, and often taken irregularly.

Cost

The patients who reported using morphine stated a street price range from 25 cents to $1 per mg—mean 56 cents/mg.

The patients who reported methadone use stated a street price range of 20 cents to $1 per mg—mean 81 cents/mg.

The one patient using oxycodone was paying 50 cents/mg.

For benzodiazepines prices ranged from 40 cents to $6 per tablet, and zopiclone $1 per tablet.

The weekly expenditure on street pharmaceuticals was tabulated at the time of assessment. Excluding those with pharmacy codeine purchasing, and those who were prescribed drugs, the mean cost was $367/week (0–2100) n=31.

Discussion

This survey, although confined to small numbers in a selected group of drug users, confirms our clinical experience over the last 15 years that the principal “street” opioids continue to be long-acting morphine tablets, and methadone solution. In the absence of evidence of morphine importation, it is likely this is mostly diverted by patients prescribed for chronic pain and malignancy; and for methadone from that prescribed by drug clinics for opioid dependence, particularly via “take-home” doses. There may also be some contribution from pharmacy/warehouse break-ins, prescription forgery, internet purchases, or even healthcare employees.

The amounts of morphine reported are likely to be accurate, as users buy the long-acting morphine in specific tablet sizes, in contrast to methadone takeaways which may be diluted by the seller. The amounts and proportions of methadone and morphine are comparable to those reported in a 1995–96 survey.4

Despite limited and sporadic supplies of imported heroin over the last 30 years, opioid misuse has continued, as judged by the increased numbers on opioid substitution treatment for dependency. These numbers have increased from 650 in 1990 to more than 4,000 currently. This probably reflects the considerable increase in prescriptions of morphine, methadone and other Class B opioid pharmaceuticals drugs over the last decade, of which a proportion is diverted to the street market.

Although there was only one patient reporting oxycodone use, it is anticipated that a range of pharmaceutical opioids will emerge onto the streets. In the US in 2002 opioid analgesics accounted for 9.85% of all drug abuse notifications, being oxycodone, morphine, hydromorphine and fentanyl, compared to 5.75% in 1997; heroin accounted for 7.7% in 2002.12

The cost of street opioids is considerable, but may be relatively lower than in the past. Adamson and Sellman4 found the average expenditure on opioids was $882 per week for patients on the methadone waiting list in Christchurch 15 years ago. It is acknowledged that there may well be regional variation in drug use patterns and price. Reasons for the apparent lower current street price of opioids may include the increased provision of opioid treatment services with relatively less opioid dependent persons not in treatment, as well as the increased prescribing of opioids.

Adamson and Sellman also confirmed the frequent association with crime to fund the drugs for opioid dependent persons.4 In addition to the social and legal issues generated by street pharmaceutical costs, injecting drug use is associated with bloodborne virus transmission and infection, sepsis, and opioid overdose. Reith et al13 have reported on opioid-related deaths in New Zealand noting the significant contribution of both morphine and methadone in unintentional deaths. They raised the issue of take-home methadone doses as a contributor.13 A Scottish study found fewer methadone-related deaths despite increasing prescriptions due to improved clinical systems around methadone provision and compliance with guidelines.14

Internationally there is awareness of methadone diversion by patients on maintenance opioids through drug clinics.15 This is of concern as it brings clinics into disrepute through paradoxically providing drugs to the very market they are attempting to treat. There is tension around perceived overly restrictive treatment conditions making programmes unattractive to drug users, versus the risks of diversion via take-home doses, which require careful individual consideration depending on clinical progress.

The factors determining “takeaway” policies are complex and include local heroin availability, treatment availability, access/waiting lists, improved retention in treatment, and employment facilitation.16 In addition Zador reflected on the high mortality from overdose in patients discharged from substitution treatment by “strict” drug clinics.17

We believe prescription opioid abuse is an important and ongoing Public Health issue in New Zealand. However it would appear to have been a lower priority for Police compared to methamphetamine, cannabis and cocaine. It received scant attention in the National Drug Policy (2007–2012). However, the proposed review of the Misuse of Drugs Act indicates an intention for better controls to prevent prescription “drug-seeking”. Some measures have been introduced, including a 10-day maximum dispensing for Class B drugs , and controlled drug prescriptions being recorded on an electronic database by Medicines Control which will improve monitoring of prescribing. There appears to be less activity regarding Drug Abuse Containment publications and propagation of the “restricted persons” schedule.

There are relatively few prosecutions by regulatory bodies or restrictions on Controlled Drug prescribing rights of doctors or other Health Practitioners for improper prescribing. To date responses from various authorities and prescribers of opioids have failed to contain this problem. Sheridan and Butler have provided an in-depth menu of strategies for reduction of prescription drug misuse in New Zealand.8

If there can be a positive in this matter, there was a recent speculative opinion proffering an alternative view that prescription drug abuse may be advantageous in harm-reduction terms, compared to heroin. Not all prescription drugs lend themselves to the injection route and doses are pharmaceutically defined. This reduces overdose risks, costs to users and acquisitive crime. Systems of unsanctioned quasi medical opioid substitution emerge, which may offer some public health benefits.18

Finally, it is acknowledged the balance between prescribing for adequate analgesia versus the risks of diversion of drugs to the street for non-therapeutic purposes is a complex issue needing research avenues.19 Attempts have been made to address these issues by a combined Australasian Medical Colleges publication on Prescription Opioid Policy.20There is a need for better information and support for doctors on analgesic-ladder prescribing, guidelines for opioid treatment of chronic non-malignant pain, and strategies to monitor patient compliance with medication.

Summary

In the absence of imported heroin into NZ, prescription opiate drugs have become the street supply. Prescription opiates have been increasingly misused in the USA. In our region, this study found morphine and methadone were the commonest street opiates being used. The costs to users of these drugs are considerable, but may be reducing. Prescription opiate misuse is a complex Public Health issue which requires multiple responses to contain.

Abstract

Aim

To survey new patients, presenting to three drug clinics, on the patterns, usage and costs of prescription pharmaceuticals.

Method

Consecutive patients seen by the medical staff for assessment had a 7-day history recorded for prescription drug (PD) usage, and the associated costs of these from street sources.

Results

There were 37 patients (26 males) with a mean age of 34 years (21–51). Ten reported using only intravenous (IV) morphine, at a median dose of 105 mg/day (40–600), at a mean cost of 56 cents/mg. Another 12 reported methadone as their sole opioid at a median dose of 50 mg/day (27–70), at a mean cost of 81 cents/mg. A further 11 used a mixture of opioids, predominantly morphine and methadone but also dihydrocodeine (3), oxycodone (1), tramadol (1) and codeine (2). Seventeen reported also using hypnosedatives, but did not report high doses of these. The overall weekly expenditure on PDs was $367/week (0–2100).

Conclusion

Morphine and methadone remain the predominant street opioid PDs in this region. Street prices have reduced, perhaps reflecting greater drug availability in accordance with increased national prescribing of opioids. There is continuing diversion of PDs to the street which is an ongoing Public Health issue requiring coordinated responses, including improved prescribing training, pain guidelines, drug clinic policy and actions by Medsafe, Police and regulatory bodies to contain this problem.

Author Information

Geoffrey M Robinson, Physician, Capital and Coast District Health Board and Medical Research Institute of New Zealand, Wellington; Graeme Judson, Medical Officer, Addictions Services, Taranaki District Health Board, New Plymouth; Richard Loan and Timothy Bevin, Medical Officers, Addictions Services, Hawke’s Bay District Health Board, Napier; Patrick O’Connor, Physician, Alcohol and Drug Service, Midcentral District Health Board, Palmerston North

Correspondence

Dr G M Robinson, Capital and Coast District Health Board, Private Bag 7902, Wellington 6242, New Zealand. Fax: +64 (0)4 3855929

Correspondence Email

Geoff.Robinson@ccdhb.org.nz

Competing Interests

None.

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