Substance abuse - opiates: heroin, methadone, and buprenorphine.
- Neurobiology of opiates
- Route of administration
- Heroin metabolism
- Patterns of use
- The effects of opiates
- Heroin (and other opiate) withdrawal
- Physical complications
- Opiate overdose
- Psychiatric comorbidity
- Social effects
- Synthetic opiates
- Buprenorphine (Temgesic, Subutex)
- Assessment of the opiate user
- Confirmation of dependence
- Management of opiate dependence
- Pharmacological interventions for opiate users: maintenance and withdrawal
- Prescribing drugs to opiate addicts
- The range of service providers and the impact of treatment
- Special groups
Opium, derived from the ripe seed capsule of the opium poppy (Papaver somniferum), has been used for its analgesic and euphoriant effects since antiquity, with Sumerian ideograms of about 4000 BC referring to the poppy as the ‘plant of joy'. The extract contains the alkaloid opiate analgesics morphine and codeine. Heroin (diamorphine) is the most commonly abused opiate, usually in the form of black-market powder which is usually injected or smoked (‘chasing the dragon'), but is also sometimes snorted. Street purity varies widely (usually 30–60 per cent). Daily consumption is commonly in the region of 0.25 to 2 g.
Neurobiology of opiates
Opiate receptors belong to the G family of protein-coupled receptors, and all inhibit adenylate cyclase and calcium channels. Two subtypes, μ and K, increase potassium conductance. Although the precise mechanisms underlying the development of tolerance to (and dependence on) opiates is not yet clear, there do not appear to be any consistent changes in opiate receptor levels. One contributory mechanism that has been suggested is the downregulation and desensitization of the opiate μ receptor. Acutely, opiates lead to the inhibition of adenylate cyclase with reduced conversion of ATP to cAMP, resulting in reduced firing at noradrenergic neurones located on the locus coeruleus. Following chronic opiate administration, there is compensatory upregulation of cAMP, returning levels towards baseline. On cessation of opiate use (or following opiate receptor antagonism) withdrawal ensues, characterized by a massive surge in unopposed noradrenergic activity (termed the ‘noradrenergic storm') from the locus coeruleus. This noradrenergic hyperactivity is thought to underlie many symptoms of opiate withdrawal, and explains the efficacy of the presynaptic a 2 agonists clonidine and lofexidine in the treatment of the symptoms of acute opiate withdrawal.
Although the changes in noradrenergic activity underlie many of the withdrawal symptoms from opiates, it is likely that other neuroadaptive mechanisms and receptor systems are at work in the development of tolerance and dependence, with recent studies indicating roles for both glutamate and g-aminobutyric acid (GABA). For example, positive reinforcement is thought to be mediated via the dopaminergic mesolimbic system. In the ventral tegmental area, GABA inhibits dopaminergic neurones, which in turn are inhibited via μ opiate receptor activation. Consequently, opiate administration leads to increased dopaminergic activity which is thought to mediate the drive to use and its positive reinforcement. (1)
Route of administration
Whilst smoking heroin is probably the most commonly used route of self-administration, many heroin users subsequently climb the ladder of routes which yield increasing bioavailability, intensity, and speed of onset of the effect, moving from snorting intranasally, through smoking and subcutaneous ‘skin popping', to intravenous use. Different types of heroin are preferentially used for different routes of administration, which themselves are markedly influenced by cultural bias; for example, chasing is common in Southwest Asia. Brown heroin from the Middle East is poorly water soluble but has a high oil content and ‘runs' well on a heated foil, which makes it better for smoking. It may also be cut with caffeine, barbiturate, or methaqualone, which increases the extractability when smoked. (2) In contrast, white heroin from Southeast Asia tends to be more water soluble and better suited for intravenous use, although it may also be snorted or smoked after preparation.
Diamorphine (half-life 2 min) is rapidly metabolized to the psychoactive intermediate 6-mono-acetyl-morphine (the only metabolite that indicates the consumption of heroin specifically as opposed to other opiates) by blood esterases before being converted to morphine (half-life 3 h). Morphine is subsequently metabolized by the cytochrome P-450 system (Cyp2D6) in the liver to codeine which undergoes conjugation before excretion in the urine. In most subjects, about 10 per cent of ingested codeine is converted into morphine, thereby giving a clinically false-positive test result for heroin/morphine. (3)
Patterns of use
Most users who come into contact with services are dependent users who, because of the duration of their use, are often at the greatest risk of opiate-related harm from either the direct pharmacological effects of the drug or the lifestyle changes that accompany drug dependence. Dependent injectors will usually inject three to six times daily to avoid the onset of withdrawal. So-called recreational use of heroin does appear to exist, (4) although this pattern is not the norm. (5)
The United Kingdom Home Office Addicts Index closed in 1997 (leaving only the informal non-identifiable regional drug misuse databases). At that time there were about 40 000 notified opiate addicts in the United Kingdom. Over the previous decade this figure had increased by approximately 20 per cent annually. Although important as a marker of the prevalence of heroin abuse in the United Kingdom, this centralized resource was of limited value since it only provided information on those who presented to doctors. The current prevalence of heroin use in the United Kingdom is thought to be less than 1 per cent (male-to-female ratio of 2:1), with most new addicts seeking treatment being in their 20s. Other indicators of the level of substance misuse include the number of arrests for possession, Customs's seizures, deaths from opiate abuse, uptake of needle-exchange programmes, and household surveys.
Good epidemiological data regarding opiate misuse among younger people are limited, although recent reports from the North of England highlight new outbreaks of heroin use among this group,(6) often through smoking. Concern over the introduction of heroin into the club scene to help the ‘come-down' from stimulant drugs is also a potentially worrying new trend. More important perhaps is the relative paucity of treatment services for young people, in terms of both accessibility and the potential consequences of introducing a vulnerable group to adult services where they may meet experienced drug users. The main initiative should be the targeting of individuals who are likely to experience problematic drug use through two main approaches:
- a better understanding of the interaction between risk factors and developmental processes may allow the development of early identification and intervention;
- a multidisciplinary skill base to address those issues which may be more pertinent in this group (e.g. family and education).
The effects of opiates
The acute psychoactive effects vary depending on dose and route, but include euphoria, sedation, emotional numbing, and induction of a dream-like state.
Heroin (and other opiate) withdrawal
Continued use of heroin (or other opiates) tends to lead to dependence and the development of tolerance (with reduced effect from a given dose or, conversely, the need for an increase in dose to achieve the same effect). Once dependence has been established, abrupt cessation or a marked reduction in dose will result in a withdrawal syndrome, much of which can be considered as a rebound from the previous opiate-induced effects. During this time there is an ‘undoing' of the neuroadaptation which had occurred during the development of tolerance and dependence. The classic withdrawal syndrome for heroin appears within 4 to 12 h, peaks at 48 to 72 h, and subsides by the end of 7 to 10 days. There is often a period of several hours before frank withdrawal symptoms begin, during which the addict becomes agitated and anxious. Characteristic withdrawal symptoms include aching muscles and joints, dysphoria, insomnia, agitation, diarrhoea, shivering, yawning, and fatigue. More objective measures include tachycardia and hypertension, lacrimation, rhinorrhoea, dilated pupils, and ‘goosefleshing' (piloerection) of the skin (hence ‘cold turkey' or ‘clucking'). Insomnia (with increase in REM sleep) and craving for the drug may persist for weeks. Opiate withdrawal is not usually considered to be life threatening.
The harm from any drug will be a function of both its direct pharmacological effects and the route of administration as well as the effects of any psychoactive adulterants or bulking agents. Problematic contamination with adulterants is rare and particulate matter is more of a problem, although there have been reports of granuloma formation in the lung and liver following injection of preparations containing talc. Approximately 60 per cent of deaths occurring in drug addicts are related to drug use, with the annual mortality for opiate-dependent users being in the region of 1 to 2 per cent, mostly from overdose.
The risk of viral transmission (e.g. HIV, hepatitis B and C viruses) is high among injecting drug users, and routine testing with counselling should be available to those at risk. Rates among users show wide geographic variation reflecting differing injecting patterns. Rates of HIV seropositivity amongst injecting drug misusers in the United Kingdom have not increased since the mid-1980s, with recent studies suggesting much lower rates of between 1 and 5 per cent among the injecting population.(7) Much of this reduction in prevalence is believed to be due to the widespread availability of ‘needle-exchange' services and provision of services focused towards ‘harm minimization'.(8) Rates elsewhere in Europe are considerably higher; those in Italy are between 30 and 80 per cent. Although opiate misusers represent the largest group of injecting drug users, some evidence suggests that rates of HIV infection among those who concurrently inject cocaine/crack or who are intravenous amphetamine users are higher than amongst their peers who use only opiates. (9) Other groups at high risk are prison populations, where injecting is more likely to involve sharing of needles, syringes, and related paraphernalia without the precaution of adequate cleaning of used equipment. (10)
Recent surveys of intravenous drug users suggest prevalence of levels in the region of 30 to 50 per cent for hepatitis B and 70 to 90 per cent for hepatitis C. (11) Prognosis is worsened by high levels of alcohol consumption, which are common in many methadone maintenance clients. (12) Therefore education and harm-reduction provision must continue in order to bring about the kind of reduction in prevalence that has been seen with HIV.
Most opiate addicts in treatment have experienced an overdose and many have witnessed it in others, (13) with those who inject being far more likely to overdose than those who smoke.(14) Variability in purity, increased central depressant effects following combination drug use (especially alcohol and benzodiazepines), generalized poor health, and high levels of psychiatric comorbidity make this a vulnerable group for both intentional and accidental overdose. There are times in an addict's career which are associated with an increased risk for overdose, for example early on in their dependence or during relapse such as that seen on return to opiate use after a period of abstinence when tolerance has fallen (e.g discharge following treatment or after release from prison).
The management of opiate overdose should be supportive with standard cardiopulmonary resuscitation and intravenous naloxone (opiate antagonist). However, intravenous access may be problematic in some users, in which case it may be quicker to give naloxone subcutaneously or intramuscularly. Admission to hospital should always be recommended, since the plasma half-life of naloxone is 1 to 2 h with the duration of effect from a single intravenous dose being as short as 45 min compared with 4 to 6 h for the physiological effects of heroin and 24 to 36 h for methadone.
Several studies have found that 70 per cent of addicts meet diagnostic criteria for a current psychiatric disorder, frequently depression, antisocial personality, and alcohol dependency. (15,16) Such diagnoses may be primary or secondary to opiate abuse, and a careful assessment of mental state and social functioning when opiate free should be performed. Many will have had childhood behavioural problems such as conduct disorder, and studies suggest that attention-deficit hyperactivity disorder, truanting, and juvenile offending are markers for subsequent use. (17) Clearly, comorbid psychiatric disorders should be treated in their own right especially if it is felt that they are important in maintaining opiate use. (18) Opiate dependence is also a strong risk factor for suicide, which accounts for up to a third of all deaths among intravenous drug users.(19)
The ramifications among the family and social environment are immense, with high rates of unemployment and divorce. Criminal conviction rates are high (70–80 per cent) with yearly rates of imprisonment being about 2 per cent. Stabilization on methadone or abstinence from opiates is associated with a reduction in associated crime.
Methadone is a synthetic orally effective opiate with a longer half-life than heroin (24–36 h), making it suitable for daily administration. It is the mainstay of treatment for heroin dependency in the Western world. A steady state plasma level is reached within 4 to 5 days, and at doses of above 80 mg it is claimed to provide a reasonable level of opiate receptor blockade such that euphoria from illicit opiates ‘used on top' is diminished. Deaths have been recorded during the induction phase onto methadone, (20) sometimes when the recipient is not as opiate tolerant as was believed or is using other opiate or central depressant drugs such as alcohol and benzodiazepines. Therefore confirmation of the patient's dependent status is paramount and should be attained by a careful and comprehensive assessment. This should not rely on self-reported drug use, but should also seek objective confirmation by repeated urine drug screens, direct observation of the patient whilst withdrawing, and assessment of the effect of a methadone dose administered on site. Most importantly, addicts starting on methadone should ideally be seen daily during the induction period, especially after three or four consecutive daily doses as a significant increase in steady plasma level is achieved after repeated dosing.
Buprenorphine (Temgesic®, Subutex®)
Buprenorphine is a partial μ-receptor agonist and k antagonist. It is used medically as an analgesic (usually sublingually), but it does possess abuse potential and may be injected. (21) However, fatal overdose from respiratory depression is believed to be less likely than with full agonist opiates, and buprenorphine is now being developed as a new drug to be in the used in stabilization and detoxification of addicts. (22)
Assessment of the opiate user
A comprehensive assessment of drug use patterns and associated risks forms the basis of any treatment plan. The most important areas are the confirmation of dependence (see below), which is a prerequisite for the commencement of substitute treatment, and an assessment of risk behaviours such as injecting patterns and other substance use. A suggested plan of enquiry that allows both accurate diagnosis and risk assessment is outlined below.
- Current consumption. How much heroin (or other opiate) is consumed on a typical day, in terms of either weight or money spent, and for how long has consumption been at this level? Where more than one opiate is being taken, amounts should be quantified, as should the amount of heroin used on a day when no other opiate is taken. The route of use (smoking, intravenous injection), number of administrations per day, and the minimum amount of drug required each day to avoid withdrawal symptoms should also be assessed. The patterns of use (and amounts) of other substances, especially central nervous system depressants such as alcohol, benzodiazepines, and other opiates such as methadone, should be established.
- Typical day. By asking users about their typical day one can elicit the appearance of withdrawal symptoms, the use of opiates to relieve these, and very often both the neglect of other interests and the primacy of drug-seeking and drug-using behaviour over other activities. Enquiries should be made about their involvement in risky drug-funding activities, such as theft and prostitution, and about their social network and nutritional intake.
- Drug use history. The age of first use and the psychosocial precipitants of use should be established, as should the development of tolerance and craving through increased frequency of use, escalating dose, and where relevant the onset of injecting.
- Psycho-sociobiological complications of use. Enquiries should be made about episodes of overdose (intentional or accidental), viral disease, imprisonment, family relationships, employment, etc. Specific attention should be paid to injecting behaviour such as use of needle exchanges, sharing equipment, and use of high-risk injection sites such as the groin and neck. Enquire about comorbid psychiatric conditions, especially depression.
- Past treatments and abstinent periods. Have they ever been in contact with treatment services or been maintained on substitute medication? Have they ever been an in- or outpatient at a detoxification unit? What was their longest period of abstinence? What has helped in the past? When and why did relapses occur? What are high-risk situations and other triggers for use? 6.
- Motivation for change. Why seek treatment now? What support is needed? Remember that clients with drug problems often present in crisis. The ‘five Ls' are often precipitants for seeking treatment and can be used to encourage behavioural change:
- L ivelihood (occupational, financial problems)
- L ife (physical health, overdose) L ove life (relationship, family problems)
- L egal problems (prison, arrest)
- L osing it (loss of control over use, mental health problems)
Confirmation of dependence
Although a diagnosis of opiate dependence may to some extent be obtainable from a full drug use history, it should be noted that corroborative confirmation of dependence (and tolerance) to opiates should be sought before commencing substitute treatment. This is of paramount importance, as the greatest risk associated with prescribing methadone is the possibility of consumption by a non-tolerant individual. Details should be sought from the general practitioner or other health-care providers. Physical examination may reveal stigmata of injecting drug use such as evidence of recent intravenous injection sites or ‘track marks' (linear scarring along veins from repeated intravenous use) on the addict's limbs. Sequential urine testing over a few days may allow the confirmation of regular opiate (although not necessarily heroin) consumption. Physiological changes consequent on opiate use, such as meiosis and sedation, may be observable in the clinic. Objective signs of opiate withdrawal (tachycardia, hypertension, sweating, mydriasis, etc.) following a period of abstinence are also very helpful in confirming dependence, especially if their reversal is observed following a measured dose of opiates administered on site, since this also indicates the level of tolerance.
Management of opiate dependence
There are three major initial considerations in the treatment of the dependent opiate user.
- How can the client be engaged within the service?
- What is the aim of the intervention (abstinence or maintenance with harm minimization)?
- What modalities should be used?
Engagement with statutory services may be through self-referral or from primary care and hospital services. Often ‘street' voluntary agencies or outreach workers will be the first point of contact, and such agencies can be important sources of information, needles, and support for the opiate user. Although methadone is often seen as one of the major attractions of engaging with services, the provision of health-care screening as well as legal and social advice can also be useful facilities to offer.
Attainment of either maintenance or abstinence may be achieved using a range of pharmacological and psychosocial interventions, with the nature of prescribing and counselling determined as much by clients and their current needs as by the agency's treatment philosophy.
Pharmacological interventions for opiate users: maintenance and withdrawal
Methadone may be used as substitute opiate drug, prescribed long term with the aim of achieving stable (non-injecting) opiate dependence (methadone maintenance) or it may be prescribed in the short term to aid withdrawal. In the latter case, a methadone mixture (usually linctus) is prescribed in a reducing dose over 10 to 21 days. Assessing the methadone dose equivalent of reported street heroin use is difficult because of the reliance on self-report and the variable purity of illicit heroin. Broadly speaking, 30 to 40 ml of 1-mg/ml mixture is approximately equivalent to 0.5 g of street heroin. Methadone gives a different urine drug screen test result from heroin with both immunoassay and chromatographic drug screening, thereby allowing non-prescribed opiate use to be identified.
Oral methadone is a cost-effective treatment either as outpatient maintenance or as a means of in- or outpatient detoxification through dose reduction. Studies suggest that a minimum effective dose in excess of 60 mg/day is required to optimize the benefit from maintenance treatment (recommended doses for substitute prescribing are above 50 mg/day), and significantly higher doses will be used in the treatment of many addicts (usual range 40–100 mg/day). However, it must be remembered that these doses are potentially fatal if taken by individuals without tolerance to the effects of opiate drugs.
The benefits of methadone treatment are as follows:
- reduced rates of injecting drugs
- reduced rates of other illicit drug use
- reduced rates of criminal activity
- reduction in suicide/overdose
- allows treatment contact with possibilities of further harm reduction.
Whilst methadone has been shown to be protective against suicide, it is worth noting that there are now proportionately more fatal overdoses involving opiates than 20 years ago. Other substitute opiates such as buprenorphine, dihyrocodeine, and even diamorphine itself have also been used, although problems of diversion of prescribed drugs and risks of continued injecting make the routine prescribing of injectable preparations of diamorphine and other opiates contentious. Clinicians in all specialties should be aware of the misuse potential for all opiate-containing analgesics to develop into iatrogenic dependence. Repeat prescriptions of such analgesics should be carefully reviewed, especially when some preparations may involve the consumption of dangerous amounts of paracetamol.
Substitute prescribing in isolation is of limited efficacy. Like insulin treatment for diabetes in the absence of other lifestyle changes, such as diet and stopping smoking, the effectiveness of methadone in the treatment of opiate dependence will be enhanced by the use of psychosocial support encouraging appropriate behavioural change. Methadone is not a treatment on its own, but encourages engagement with services and forms one part of a multidisciplinary psychosocial pharmacological treatment package.
Management of opiate withdrawal
Although a slow reduction in the dose of a full agonist (or a partial agonist such as buprenorphine) may be used to detoxify dependent users, other methods are now available. The a 2 agonists clonidine and lofexidine may also be used to alleviate the distress associated with the central noradrenergic hyperactivity that is responsible for many of the symptoms of opiate withdrawal. The dose of lofexidine should be titrated against the symptoms and signs of withdrawal, while being careful to avoid hypotensive episodes. Lofexidine may be used in both outpatient and inpatient settings; it can significantly reduce the discomfort of withdrawal and is as effective in opiate withdrawal as methadone. (23,24) Lofexidine should be considered as the preferred non-opiate method of assisting opiate withdrawal and can safely be used in conjunction with benzodiazepines and simple analgesics. Withdrawal may also be hastened by administering the long-acting opiate antagonist naltrexone, which ‘kicks' the addict into intense but shorter-lived withdrawal during which symptomatic relief may be given with clonidine and benzodiazepines. (25) In others this precipitant withdrawal is speeded up even further, with the detoxification procedure being completed under general anaesthetic in about 24 h, although this is not without risk. (26) In the future, the use of buprenorphine and the long-acting L-a-acetyl methadol (LAAM) as substitute opiates for long-term maintenance may become more widespread.
Prescribing drugs to opiate addicts
In the United Kingdom all doctors may prescribe methadone for the treatment of dependence and other opiates for analgesia or other clinical indications except dependence. Only doctors in possession of a Home Office license are able to prescribe heroin for the treatment of dependence. In recent years there has been growing concern over the diversion of licitly prescribed methadone to the illicit ‘grey' market, with such diversion contributing to many of the deaths related to methadone (i.e. in non-tolerant users). Prescriptions for abusable drugs like methadone may contain directives that determine how and when the prescription is dispensed by the pharmacist, and such considerations may limit the diversion of such drugs. For example, the prescription may dictate that the drug is dispensed daily from a named pharmacist or, as is increasingly the case in some areas, methadone is prescribed so that it is taken on site in the pharmacy (supervised administration) or is administered daily from a specialist clinic. Liaison between the pharmacist, the general practitioner, and the specialist is likely to become more important as these shared-care approaches become more commonplace. Supervised daily consumption of methadone and the integration of primary care in treatment delivery to drug users are both recommendations laid out in new United Kingdom government guidelines for the management of drug misuse (the ‘Orange Guidelines'). (27)
The range of service providers and the impact of treatment
Those who experience problems with opiates may present to wide range of professionals within the health-care, social, and legal systems. The range of treatment options available within statutory and non-statutory agencies will vary, as will the provision of either maintenance or detoxification for opiate dependents depending upon differing treatment philosophies and treatment settings. Partly in response to this diversity of resource provision, an ongoing multicentre prospective outcome study (National Treatment Outcome Research Study) was set up in 1995 to compare the impact of different treatment approaches on subsequent drug use as well as upon psychosocial and physical outcomes. Preliminary results (28) suggested that all four types of intervention (residential rehabilitation, inpatient drug dependency units, methadone maintenance, and reduction) led to reductions in illicit drug use and criminal activity as well as reductions in injecting and sharing behaviours. Least impact was noted on heavy alcohol consumption, which is a particular problem in those with hepatitis C. Recent results from the same group suggest that for every extra £1 spent on treatment, there is a return of more than £3 in cost savings associated with lower levels of victim costs of crime and reduced demands upon the criminal justice system.
There are numerous psychological approaches that are currently used in the management of substance misusing individual including cognitive-behavioural therapy, relapse prevention, and psychotherapy (individual, family, and group). The most influential approach in recent years has been the relapse prevention model, (29) which includes identification of cues or triggers for craving (often people, places or paraphernalia, or a certain mood state such as boredom or stress) and learning techniques (distraction, relaxation, imagery) to handle high-risk situations. Recently, motivational interviewing, based on the work of Miller in the United States, has become increasingly popular. It aims to move the client along a ‘cycle of change' (30) from pre-contemplator (no interest in changing current using behaviour) to contemplator, and then to determination and action without confrontation. (31) MotivationaI interviewing is based on five key principles that have utility within the fields of both addiction and eating disorders, but may also be used in any aspect of the doctor–patient relationship where the patient is ambivalent about implementing a change that in the doctors opinion would be beneficial. The five principles are:
- express empathy
- help the client to see discrepancies in their behaviours
- avoid argument
- roll with resistance
- support the patient's sense of self-efficacy.
This is very different from the usual paternalistic and authoritarian approach on which doctors are reared. It is not enough for doctors to expect patients to do something just because the doctor tells them to do it. People only successfully change their behaviours when they perceive that they are able to (perceived competence) and that they will be better for it. Motivational interviewing is a technique that all health-care professionals could utilize to great therapeutic effect, and we strongly recommend anyone interested in improving their ability to assist any of their clients to implement change in a successful manner to read the referenced text. (31) Involvement with Narcotics Anonymous and support groups such as Mainliners should be encouraged.
Many addicts, especially those who are homeless, do not engage with or have access to primary health care services. High levels of physical and psychiatric morbidity may go undetected or untreated, and increasingly local drug services are finding themselves as stopgap providers of basic medical care ensuring adequate nutrition, contraception, screening, and check-up facilities. Shared care between drug agencies and primary care should be encouraged, with special attention focused on provision of hepatitis testing and vaccination to all users.
Social and educational support
The drug user may stand alone, but all available potential supports should be considered whether family, friends, or support agencies such as Narcotics Anonymous. Educating the drug user about safe practices and harm-reduction techniques is important, as is appropriate liaison with other agencies such as social services or voluntary sector supports. Therapeutic communities and ‘concept houses' based on a religious or abstinent theme offer longer-term care.
Young people with opiate problems often have other emotional and/or behavioural problems, and frequently fall between the adult and child psychiatric services as well as the addiction services, compounding difficulties in the delivery of service. In addition to the absence of a dedicated service for young people with substance misuse problems, there is the added problem of engaging this group with services. There is a twofold need to break down the ‘us and them' barrier at the patient–doctor and the child–adult level. Service delivery is further compounded by the need to address developmental issues, cognitive and emotional immaturity, education rather than employment problems, and the greater importance of the family and child protection issues. These issues are uncommon in the adult addiction service and this points to the need for the development of a new skill base. Such a service should be comprehensive, competent, child centred, and lawful. Separation of such a service from adult providers would also assist in preventing experienced drug users from influencing more naive users. Ultimately a tiered approach would appear appropriate, since it would allow maximum utility of current services and focused development of new services. Generic services in primary health care could provide accurate screening with initial referral to youth-oriented services within existing departments. Beyond this, referral to specialist and super-specialist regional services could be employed to provide secure environments with the option of residential rehabilitation and therapeutic communities. Full and accurate assessment will be the key issue, with the adage of history, examination, and special investigations being as valid here as elsewhere in medicine. It will only be through early identification and accurate assessment that this vulnerable group will be accessible to service providers. Once engaged they will be able to receive the full range of possible therapies from family work and cognitive-behavioural therapy to pharmacotherapy and self-help groups.
Maternal opiate use abuse may harm both mother and fetus with damage mediated through the bio-psychosocial consequences of drug use. For the injecting drug user, continued exposure through risk behaviours to pools of infections combined with vertical transmission makes intervention in this group of paramount importance. Increased rates of stillbirth, premature birth, antenatal complications, low birth weight, and neonatal withdrawal are all associated with maternal opiate use, through the pharmacological and lifestyle consequences of drug use. In considering the management of the pregnant drug user, liaison between the primary health care team (especially if also the prescriber) and the drug and pregnancy services is paramount to promote both engagement and compliance with treatment.
General aims of managing the pregnant drug user
- Engage the patient.
- Maintain contact with the patient.
- Promote the health and well being of the mother and fetus.
- Aim to reduce risk-taking behaviours (sharing needles, prostitution).
- Stabilize on non-injectable alternatives such as methadone.
- If considering detoxification, this should be done in the middle trimester.
- Provide good primary health (nutrition) and psychological care.
- Liaise with obstetric, midwifery, and paediatric teams, and with social services where appropriate.
- Social stability and provisions for motherhood.
- Social work/parenting assessment.
- Ensure that other drug and alcohol behaviours are assessed.
- HIV and hepatitis screening (vaccination where appropriate).
Stabilization of the mother on an oral substitute drug should always be the initial aim. Where possible, the mother should be encouraged to become abstinent prior to delivery—indeed this is often what both doctor and mother want. However, such a move may not always be in the best interests of the infant and mother, and it may often be more appropriate to keep the mother in contact with services on low-dose maintenance. The long-term outcome in women who enter methadone treatment programmes during pregnancy is better in terms of their pregnancy, childbirth, and infant development, irrespective of continuing illicit drug use. (27)
Although there is no clear relationship between maternal methadone dose and the intensity of neonatal withdrawal (or likelihood of experiencing it), the pregnant opiate user should be encouraged to try and reduce the dose since lower doses (15 mg) are probably associated with a reduction in severity of neonatal withdrawals. Benzodiazepines and opiates are slowly metabolized by the newborn infant, so that peridelivery administration may result in hypotonia and respiratory depression. Both opiate and benzodiazepine dependence in the mother may be associated with protracted withdrawal syndromes in the infant, with the risk of seizures. There is some evidence to suggest that transferring the pregnant mother onto buprenorphine during the second trimester is associated with lower rates of neonatal withdrawal. Methadone is not a contraindication to breast feeding, although there is wide variation in local recommendations. Issues such as maternal nutritional and viral status also need to be taken into account when deciding whether breast feeding is appropriate.
About one-third of remand prisoners have a substance abuse dependency problem, most commonly alcohol and opiates. Access to illicit substances is not prevented by imprisonment; indeed some users may increase their ‘habit' while in prison. Poor levels of identification on screening at entry and as yet inadequate prison treatment services and court diversion schemes for drug-dependent offenders mean that their considerable needs will continue to be unmet. Education and good primary health care are vital. Recent interest in drug treatment and testing orders may allow those dependent users who are convicted of crimes associated with acquisitive offending to receive a treatment order as opposed to a custodial sentence.
There are high rates of comorbidity of personality disorders, depression, and anxiety disorders among opiate users, with the severity of premorbid pathology being an important determinate of outcome. (32) Appropriate assessment and treatment of depressive disorders is important in reducing relapse rates and maintaining engagement, remembering that suicide accounts for a high percentage of deaths in opiate users. Again, liaison with adult mental health teams is important.
Reducing high-risk behaviours by those with HIV is important in limiting the spread of the disease. Stabilization on methadone with abstinence from injecting, needle-sharing, and unprotected sex should be encouraged. Liaison with medical and psychiatric services is important.
Outcome in opiate dependence is not unitary. It is a dynamic process with bio-psychosocial facets. Outcome parameters may include the individual's level of alcohol and drug use, his or her personal and social functioning, and the impact upon public health and safety. Figures will depend on the particular population of users that is followed up and on the level of intervention they received. Regarding treatment contact samples, what is clear is that longer treatment contacts are associated with better outcomes. (33) It is thought that methadone treatment has to continue for at least 2 years for significant gains to be made, although earlier health benefits may be seen.
Generally, the greater the range of treatment services provided (health care, family therapy, cognitive-behavioural therapy, etc.), the better is the outcome. (34) Abstinence rates following treatment vary widely, but 10 to 40 per cent of treated patients would still be drug free at 6 months. (35) The majority of those who relapse following treatment do so within 3 to 4 months of discharge. The greater the severity of pretreatment psychopathology and dependence the worse is the outcome. Suicide and accidental overdose account for between one-third and half of all death of opiate addicts, with risk factors including alcohal use, recent dropout from treatment, and social isolation. A 22-year follow-up of 128 heroin addicts revealed that 43 had died (18 due to drug over-dose), with annual mortality running between 1 and 2 per cent, and an excess mortality ratio of about 12. (36) Among the strongest correlates of mortality in this group are level of disability, heavy alcohol use, heavy criminal involvement, and tobacco use.
Long-term follow-up studies suggest that eventual cessation of opiate use is a very slow process and becomes increasingly unlikely if users continue into their late thirties. Chapter
1. Simonato, M. (1996). The neurochemistry of morphine addiction in the neocortex. Trends in Pharmacological Science, 17, 410–15.
2. Strang, J., Griffiths, P., and Gossop, M. (1997). Heroin in the United Kingdom: different forms, different origins, and the relationship to different routes of administration. Drug and Alcohol Review, 16, 329–37.
3. Wolff, K., Farrell, M., Marsden, J., et al. (1999). A review of biological indicators of illicit drug use, practical considerations and clinical usefulness. Addiction, 94, 1279–98.
4. Blackwell, J. (1983). Drifting, controlling and overcoming: opiate users who avoid becoming chronically dependent. Journal of Drug Issues, 13, 219–35.
5. Zinberg, N. (1984). Drug, set and setting: the basis for controlled intoxicant use. Yale University Press, New Haven, CT.
6. Parker, H., Burry, C., and Eggington, R. (1998). New heroin outbreaks amongst young people in England and Wales. Police Research Group, Home Office, London.
7. Crawford, V. (1997). Injecting drug use. Current Opinions in Psychiatry, 10, 215–19.
8. Stimson, G.V. (1995). AIDS and injecting drug use in the UK, 1987–1993: the policy response and the prevention of the epidemic. Social Sciences and Medicine, 41, 699–716.
9. Hunter, G.M., Donoghue, M.C., and Stimpson, G.V. (1995). Crack use and injection on the increase among injecting drug users in London. Addiction, 90, 1397–1400.
10. Power, K.G., Markova, I., Rowlands, A., McKee, K.J., Anslow, P.J., and Kilfedder, C. (1992). Intravenous drug use and HIV transmission amongst inmates in Scottish prisons. British Journal of Addictions, 87, 35–45.
11. Fingerhood, M.I., Jasinski, D.R., and Sullivan, J.T. (1993). Prevalence of hepatitis C in a chemically dependent population. Archives of International Medicine, 153, 2025–30.
12. Best, D., Lehmann, P., Marsden, J., Farrell, M., and Strang, J. (1999). Eating too little, smoking and drinking too much; wider lifestyle problems among methadone maintenance patients. Addiction Research, 6, 489–98.
13. Powis, B., Strang, J., Griffiths, P., et al. (1999). Self reported overdose among injecting drug users in London: extent and nature of the problem. Addiction, 94, 471–8.
14. Gossop, M., Griffiths, P., Powis, B., Williamson, S., and Strang, J. (1996). Frequency of non-fatal heroin overdose. British Medical Journal, 313, 402.
15. Rounsaville, B.J., Kosten, T.R., Weissman, M.N., and Kleber, H.D. (1986). Prognostic significance of psychopathology in treated opiate addicts: a 2.5 year follow up study. Archives of General Psychiatry, 43, 739–45.
16. Robins, L.N. and Reiger, D.A. (ed.) (1993). Psychiatric disorders in America: the Epidemiologic Catchment Area Study. Free Press, New York.
17. Lloyd, C. (1998). Risk factors for problem drug use: identifying vulnerable groups. Drugs: Education, Prevention and Policy, 5, 217–32.
18. Hall, W. and Farrell, M. (1997). Comorbidity of mental illness with substance misuse. British Journal of Psychiatry, 171, 4–5.
19. Frischer, M., Bloor, M., Goldberg, D., Clark, J., Green, S., and McKeganey, N. (1993). Mortality among injecting drug users: a critical reappraisal. Journal of Epidemiology and Community Health, 47, 59–63.
20. Caplehorn, J. and Drummer, O.H. (1999). Mortality associated with New South Wales methadone programs in 1994: lives lost and saved. Medical Journal of Australia, 170, 104–9.
21. Hammersley, R., Lavelle, T., and Forsythe, G.A. (1990). Buprenorphine and temazepam abuse. British Journal of Addictions, 85, 301–33.
22. Ling, W., Charuvastra, C., Collins, J.F., et al. (1998). Buprenorphine maintenance treatment of opiate dependence: a multicentre randomised clinical trial. Addiction, 93, 475–86.
23. Bearn, J., Gossop, M., and Strang, J. (1996). Randomised double blind comparison of lofexidine and methadone in the inpatient treatment of opiate withdrawal. Drug and Alcohol Dependence, 43, 87–91.
24. Strang, J., Bearn, J., and Gossop, M. (1999). Lofexidine for opiate detoxification: a review of recent randomised and open controlled trials. American Journal of Addictions, 8, 366–77.
25. Kleber, H.D., Topazian, M., Gaspari, J., et al. (1987). Clonidine and naltrexone in the opiate treatment of heroin withdrawal. American Journal of Drug and Alcohol Abuse, 13, 1–17.
26. Bearn, J., Gossop, M., and Strang, J. (1999). Rapid opiate detoxification treatments: a review. Drug and Alcohol Review, 18, 75–81.
27. Department of Health (1999). Drug misuse and dependence: guidelines on clinical management. HMSO, London.
28. Gossop, M., Marsden, J., Stewart, D., et al. (1997). The NTORS in the UK. Six month follow up outcomes. Psychology of Addictive Behaviours, 11, 324–37.
29. Marlatt, G.A. and Gordon, J.R. (ed.) (1985). Relapse prevention: maintenance strategies in the treatment of addictive behaviour. Guilford Press, New York.
30. Prochaska, J.O. and Di Clemente, C.C. (1986). Towards a comprehensive model of change. In Treating addictive behaviours: process of change (ed. W.R. Miller and N. Heather). Plenum Press, New York.
31. Miller, W. and Rollnick, S. (1991). Motivational interviewing. Guilford Press, New York.
32. Rounsaville, B.J., Wiseman, M.M., Kleber, H., and Wilber, C. (1982). Heterogeneity of psychiatric diagnosis in treated opiate addicts. Archives of General Psychiatry, 39, 161–6.
33. Simpson, D., Joe, G., and Brown, B. (1997). Treatment retention and follow up outcomes in the Drug Abuse Treatment Outcomes Study (DATOS). Psychology of Addictive Behaviours. 11, 294–307.
34. McLellan, A.T., Arndt, I.O., Metzger, D.S., Wood, G.E., and O'sBrien, C.P. (1993). The effects of psychosocial services in substance abuse treatment. Journal of the American Medical Association, 269, 1953–96.
35. McLellan, A.T., Alterman, A.I., Metzger, D., et al. (1994). Similarity of outcome predictors across opiate, cocaine and alcohol treatments: role of treatment services. Journal of Consulting and Clinical Psychology, 62, 1141–58.
36. Oppenheimer, E., Tobutt, C., Taylor, C., and Andrew, T. (1994). Death and survival in a cohort of heroin addicts from London clinics: a 22 year follow up study. Addiction, 89, 1229–1308.