Prescribing opioids for drug misusers
Palliative care mainly relates to patients with cancer, although it also treats those with non-malignant disease. This means that expertise in the field is generally derived from a single diagnostic grouping, with similar needs. Evidence concerning problem drug use in the palliative care setting is sparse and few studies have looked at iatrogenic problem drug use. However, this is a growing area of concern (see case studies) and one that physicians may need to consider more closely in future.
The incidence of substance misuse varies widely and has been quoted as 6-15 per cent in the US population. In chronic pain services, however, this figure rose to 41 per cent.1 This depends on services looking specifically for the problem, as in one study of a cohort of 233 patients with a non-cancer diagnosis, taking long-acting oxycodone and followed up for three years. In this group, the researchers found only evidence of possible misuse in 2.6 per cent, with no de novo addictions.2
Up to 90 per cent of patients at the end of their life will experience pain3 and this figure can rise if the patients are substance misusers.4
Several Scandinavian studies have found similar rates to those in the US groups, although it was felt that few screening tools were well validated or reliable. However, most guidelines identified addiction as a potential problem. It was presumably with this in mind that the British Pain Society published its guidance on prescribing for substance misusers (see Box 1).5
A recent study in Uppsala, Sweden,6 looked at methadone treatment for patients with chronic non-malignant pain and opioid dependence. Unusually, the researchers studied pain relief and quality of life indices. They found that far from causing problems, their patient group had a higher global quality of life score than the chronic pain group in Sweden, and of 48 patients, only four dropped out because of drug diversion (passing their prescribed drugs to other misusers).
Prescribing opioids for substance misusers
When prescribing opioids for substance misusers, it is essential to involve the multidisciplinary team, including the pharmacist, mental health worker, palliative care team, substance misuse team, and pain team. The focus should be on primary care, because this is where patients will receive most of their treatment. The patient's misuse history should be assessed at an early stage. By being clear and open, the team can take a non-judgmental approach. Careful documentation is needed to prevent prejudicial treatment from other professionals.
Any mental health problems should be identified, evaluated and treated. Then realistic goals should be set; 80 per cent of patients with addiction problems will relapse within a year.7 Total compliance and abstinence may not be achievable and frequent team meetings will be needed for goal adjustment.
Treat the pain properly. Individualisation of the drug dose needed to achieve analgesia is important. Tolerance may necessitate large doses, which some prescribers find difficult because they assume the cause to be aberrant behaviour.
The relationship between patient and prescriber relies to some degree on trust and with that trust must come an explicit set of rules. If the two parties agree to a contract that sets out these rules and defines the consequences of aberrant behaviour, this will provide boundaries for care. These have to be structured for individuals and the clinical setting.8 It is beneficial to be clear about what will happen in the event of prescription loss or adjustment and to communicate that there will only be one named prescriber. Covering clinicians should also be made aware of the contract.9
The prescriber must be prepared to take action if the contract is broken, because all authority is removed unless you are prepared to remove the patient from the unit. This may be difficult to do because it does not feel like palliative care; hence the need for discussion with the multidisciplinary team.
Comorbidities and drug interactions
In a drug-misusing population, it should be remembered that there are often other pathological problems, such as
hepatitis, HIV, cardiac and renal insufficiency, mental health disorders and poor nutrition. Patients may have come from poor social conditions where other members of the household are substance misusers, leading to diversion of prescribed drugs. Drug interactions should also be considered (see Box 2 for possible interactions). Prescribers are advised to contact the HIV pharmacist to discuss this.
There is very little guidance for palliative opioid prescribing in patients with a history of substance misuse. Case histories and personal experience show that palliative care teams have skills that can be applied in working with patients who have drug misuse problems. These patients may not be the stereotypical drug user, but it is beholden on palliative care providers to be equipped to manage their pain safely and well.
|Dr. Chris Farnham is medical director and consultant in palliative care, St John's Hospice and UCH, London. Competing interests: None declared|
1. Manchikanti L. Controlled substance abuse and illicit drug use in chronic pain patients. Pain Phys 2006;9(3):215-25.
2. Portenoy RK. Long term use of controlled release oxycodone for non cancer pain - a 3 year registry study. Clin J Pain 2007;23(4):287-99.
3. Kane RL, Wales J, Bernstein L et al. A randomised controlled trial of hospice care. Lancet 1984;1:890-4.
4. Seale JP. Substance abuse among minority populations. Sub Abuse 1993;20(1):167-80.
5. British Pain Society. Pain and substance misuse: improving the patient experience (consensus document). August 2006.
6. Rhodin A, Gronbladh L, Nilsson LH, Gordh T. Methadone treatment of chronic non malignant pain and opioid dependence - a long term follow up. Eur J Pain 2006;10(8):271-8.
7. Passik SD. Substance abuse issues in cancer patients part 2:evaluation and treatment. Oncol 1998;12(5):729-34.
8. Kemp C. Managing chronic pain in patients with advanced disease and substance related disorders. Home Health Nurs 1996;14(4):225-61.
9. Kirsh KL. Palliative care of the terminally ill drug addict. Cancer Invest 2006; 24: 425-31.
Originally published in the June 2008 edition of MIMS Oncology & Palliative Care.