May 2007: Harm reduction the key to managing problem drug users
How are GPs involved in managing drug addiction?
How can patients be assessed?
Which treatments are effective?
How are GPs involved in managing drug addiction?
How can patients be assessed?
Which treatments are effective?
?the effective management of drug misusers involves the detection of harm related to drug misuse, reducing that harm and retaining the patient to ensure that they make the necessary lifestyle changes to prevent further harm to themselves, their family and the wider community.1 In the UK, four million people a year use illicit drugs, and one million of these use heroin and cocaine, in a market worth £6.6bn.2 Illicit drugs are involved in a third of fatal road traffic accidents and homicides.2 There are an estimated 250,000-300,000 problem drug users in England and the most recent figures show that 125,500 of these are receiving treatment.3 Drug users have 13 times the mortality rate of the general population.4,5 More screening is now needed to detect these problem drug users and motivate them to engage with effective interventions.6,7
The model for drug services was updated in 2006.8 The updated model has four tiers of ‘drug interventions' rather than a classification of services as in the 2002 model.9 These are summarised in table 1, attached. Each successive tier has increasing patient commitment and specialist input. Many agencies are involved, necessitating cooperative, shared care.8,9
A specialist in this context is someone who manages substance misuse exclusively. This is usually – but need not always be – a psychiatrist.
Various epidemiological studies from 1990 to 2001 have found lifetime prevalences of 16.7-22% for substance-related disorders in the general population.10-12 The one year prevalences of substance-related disorders range from 4 to 7%.10-12
Smokers are 12 times more likely to be dependent on another substance than non-smokers, and people with alcohol-related harm are six times more likely than those who use alcohol safely.12 Substance users place increased demand on all types of medical services.4 Opiate users place the greatest demand on services and are likely to have spoken to their GP about their problem.4
Screening for hazardous drug consumption is done by biochemical testing, questionnaires or clinical interviewing. The use of a checklist can enhance history taking. In general, the most reliable information that can be gained from the patient will relate to current use over the previous 24 hours. However, it is helpful when assessing change to enquire in a systematic manner about longitudinal use.13 The Maudsley Addiction Profile14 is a useful tool; a modified version is shown in figure 1, attached. This is a low threshold drug screen that evaluates the past 12 months.
Chemical testing of biological fluid is the most objective means of diagnosing drug use. The fluid sample must be collected by a reliable method and supervision of sampling is essential to prevent dilution or contamination.1 Urine testing is the method of choice and the most frequently used. Table 4, attached, shows how long the various drugs and their metabolites can be detected in urine following ingestion.
Rapid detection devices or near-patient test kits have recently been developed. The great advantage of these tests is they can be done on site to obtain a rapid result. The disadvantage is that there are limitations to the accuracy of the result, and any result must be confirmed by laboratory assay.15
These tests should only be used and interpreted by trained staff.
• Saliva has a great advantage over urine in that it is easy to collect. Some oral swabs contain irritants to cause buccal bleeding and in effect provide a blood sample.
The disadvantage of saliva testing is that it is expensive and results still need to be confirmed by laboratory testing, which is the gold standard. In the future, with further refinement, this form of testing is likely to prove very useful.16
• Hair testing is at the development stage. It has the advantage that the detection period can be as long as three months.16
• Blood testing is accurate and best used for monitoring drug levels.
Blood testing is mandatory before commencing a patient on opiate substitution with either methadone or buprenorphine.16
A reliable positive opiate test needs to be obtained before opiate substitution is initiated.1
Dependent opioid use is associated with increased mortality, mostly because of respiratory depression following accidental overdose. The sites used to inject drugs, and the consequences, are summarised in table 5, attached. Opioids are the drugs most commonly injected, but cocaine, benzodiazepines and barbiturates are also used intravenously. If veins are destroyed, then injection into the skin or muscle can occur. As well as local infection, there may be dissemination of bacterial infection to other sites such as the lung, brain, bone and heart.5
Stimulants such as cocaine and amphetamines raise blood pressure and heart rate, and can lead to arrhythmias, cardiac failure, myocardial infarction and cerebrovascular accidents.5 Table 6, below, summarises the local effects of cocaine.
Common side-effects at recreational doses include a dissociative state, perceptual changes and hallucinations.
Drug dependence is treated by a combination of pharmacotherapeutic and psychosocial interventions. Trials report benefits of drug misuse treatment, for example in the National Treatment Outcome Research Study (NTORS) rates of injecting dropped from 61% to 29-37% depending on the setting.17 Although abstinence is the ultimate harm reduction, it is difficult to achieve – hence the focus on modifying behaviours.
A significant factor in achieving better outcomes is treatment retention, as the longer a patient is kept in treatment the greater the lifestyle changes.17 The harm reduction model aims to reduce risk behaviours to prevent viral, especially HIV, spread and reduce crime by interventions that encourage safer and reduced use of drugs. The concept of harm reduction was developed in the context of reducing HIV?spread, and prevention of HIV also leads to prevention of hepatitis B spread. Harm reduction now aims to prevent hepatitis C spread, but this has been less successful. The components of this approach are listed in table 7, below. The effectiveness of needle exchanges in reducing HIV transmission with no increase in level of injecting is well established.
Harm reduction is now embracing resuscitation training and take-home naloxone in response to the high mortality rate among opiate users. Most of these deaths are caused by accidental overdoses and it is estimated that up to two-thirds of them are preventable.18
The effectiveness of brief interventions such as simple advice and education is well established in the treatment of alcohol-related problems. There is less evidence available about their use in drug misuse, but it is reasonable to assume that, with their use, 25–45% of patients would reduce their drug use significantly.19
Drug counselling has been shown to be more effective than no intervention, with a competent therapist and longer, rather than more intense, therapy producing the best outcomes.20
Support groups improve the patient's environment by recruiting family, friends and local community resources to support the patient. Narcotics Anonymous is a formal support group of former drug addicts.
Motivational interviewing is a therapy that helps the patient to develop the motivation to change.21 This is done by encouraging the patient to elicit problems with his/her substance use, define them, acknowledge the benefits of changing and translate this into goals. The essence of this technique is that the therapist acknowledges the positive aspects of drug use, which then encourages the patient to look at the negative aspects of drug use. It has a good research base that demonstrates its effectiveness.19
Even as few as three sessions can be effective, suggesting that this approach can be adapted to a general practice setting.
Relapse prevention and cognitive behaviour therapy assume that substance misuse is a means of coping and the patient is taught how to manage high-risk situations using alternative cognitive and behaviour strategies. Even though patients usually attend only 50% of the time, there is a modest overall effect.5
Detoxification from opiates is one of the most widely used treatments but one of the least effective, as the majority of opiate addicts cannot sustain abstinence over the long term.
Methadone has a half-life of 24 hours. This allows once-daily dosing and a steady state is reached after four to five days. Once the patient is stabilised, detoxification is done gradually to ensure that the symptoms are tolerable. Clonidine and lofexidine reduce the somatic symptoms of withdrawal. There is no difference in outcome between these agents and methadone in detoxification.22,23,24 Both can cause hypotension and sedation, but lofexidine less so than clonidine. Ultra-rapid opiate detoxification under general anaesthesia is not effective and there are serious concerns about safety.25
The safety and efficacy of methadone maintenance has been unequivocally established.26 An effective dose is usually 60-120mg a day and must be accompanied by appropriate psychosocial intervention.22,24,27
Buprenorphine is comparable in effectiveness to methadone.22,23,27
It has the advantage that there is less risk of overdose and a smoother withdrawal, but it is more expensive and has a higher risk of being injected.
A buprenorphine and naloxone combination preparation has recently been licensed for use in the UK. Naloxone is an opioid antagonist that only has bioavailability if taken parenterally. The buprenorphine and naloxone combination may prevent street diversion for IV use. The rationale is that if the combination is injected it induces opioid withdrawal, which is not the case if taken sublingually as prescribed.
Naltrexone is used to prevent relapse, as it prevents the euphoria and other effects of heroin. It is indicated for those with opioid dependence seeking to maintain abstinence, who are highly motivated.28
Antidepressants, dopamine antagonists and anticonvulsants have been used for detoxification from stimulants, but the evidence for their effectiveness is not convincing.23,24 This is in contrast to the evidence for psychosocial interventions, which is the treatment of choice for stimulant-related problems.
Over the past decade the increase in drug misuse has been matched by the development of effective treatments for drug misuse. These interventions are being honed further to give more tailored treatments. The NTORS study recruited more than 1,000 patients from 54 community and residential programmes. The study evaluated
four broad types of treatment, maintenance, detoxification, short-term and long-term residential services. At four- to five-year follow-up, this study showed sustained significant improvement in outcome.17 The NTORS study shows that curbing the rise in substance-related problems is possible, as six-month outcomes for primary care services positioned to treat opiate addicts are comparable with those achieved by more specialised services.29
The 2005 report on the UK drug situation found that the harm caused by drug use had fallen by 9% since the launch of the Government's drug strategy.3Authors
Dr William Flannery
specialist registrar, National Alcohol Unit, Maudsley Hospital, London
Dr Michael Farrell
senior lecturer, National Addiction Centre, London, and consultant psychiatrist, South London and Maudsley NHS Trust