13. Substance Misuse Definitions Misuse or abuse this is the taking of something with the intention of producing pleasurable mind-altering effects, intoxication or altered body image. The mind-altering effects often include a buzz, high or rush a sudden intense euphoria after intravenous use or inhalation. The generalised term substance misuse includes misuse of things not traditionally labelled as drugs (e.g. alcohol). Dependence this occurs when someone develops a need to keep taking a drug every day even though there may be physical, behavioural or mental impairment as a result. Drug taking, and the results of it, can consume a large proportion of these people s time, and they may feel out of control. The user may show tolerance and withdrawal reactions. For some substances, daily administration for a long time is needed to cause dependence (e.g. alcohol), for others a few doses may be enough (e.g. IV stimulants). Withdrawal this is an established pattern of symptoms which occur when regular use of a drug is curtailed, the dose reduced or an antagonist is given. Tolerance this happens when the body adapts to the continued presence of a particular dose of a drug so that the desired effects are diminished. In practical terms the dose of a drug required to produce the effects can be increased to counteract this. Principal Drugs Involved The grouping of drugs into convenient categories for discussion is fraught with difficulties. However, one grouping according to predominant pharmacological effects would be: Stimulants cocaine, amphetamine, caffeine, OTC decongestants (e.g. pseudoephedrine). CNS depressants opioids, alcohol, benzodiazepines, volatile substances. Drugs altering perception LSD, cannabis, ecstasy, gamma hydroxybutyrate, ketamine. Tobacco. Drugs altering body image anabolic steroids. Routes of Administration Most street drugs can be given in a variety of different ways. Some are commonly taken orally such as ecstasy, LSD, benzodiazepines and certain types of anabolic steroid. However, the majority are administered by injection (cocaine, heroin, amphetamine, anabolic steroids) or via the airways; both routes carry a greater dependence potential than oral administration. Airways administration involves heating drugs up to make a vapour (e.g. solvents, crack cocaine), smoking (e.g. cannabis, heroin) or nasal inhalation of a dry powder (e.g. amphetamine, cocaine). 13.1
Withdrawal For drugs that can cause a withdrawal reaction, the duration of continuous daily exposure is probably the biggest determinant of whether it will actually occur when drug administration ceases. However, for any given drug not all patients will actually experience withdrawal; it is only seen in one third of chronic benzodiazepine users, for example. Also, the severity and duration of withdrawal varies considerably between drugs and between individuals. When assessing a patient for withdrawal symptoms, look for objective signs of withdrawal rather than relying totally on what the patients says (i.e. don t rely on subjective signs alone). Some drugs do not classically produce a major withdrawal reaction. Examples include anabolic steroids, cannabis and LSD. For those that do, typically the withdrawal effects are broadly opposite in character to their usual effects (e.g. amphetamine/cocaine withdrawal causes tiredness, lethargy and depression; benzodiazepine withdrawal causes anxiety and insomnia). Where withdrawal is a known potential problem, there are four basic methods of dealing with it: 1. Unmedicated Cessation. In highly motivated individuals it may be acceptable to simply stop the substance in question without any prescribed medication. Personal motivation and the support of others are important determinants of success (e.g. an option for many tobacco smokers). 2. Gradual Withdrawal. For other drugs, such as benzodiazepines and opioids, a gradual tapering down of the levels of drug exposure can be used to help wean the patient off. Sometimes the misused drug is substituted with a long-acting alternative first (e.g. methadone in heroin users, diazepam in benzodiazepine dependents). This tends to make the withdrawal less intense although it does last longer. 3. Support Medication. For some drugs, the best option may be to stop with agreed support medication (e.g. antidepressants in stimulant users, benzodiazepines in alcohol withdrawal). These medicines don t stop the withdrawal, but they make it more bearable. 4. Substitution Therapy (Not Withdrawing). For example chronic maintenance on methadone. Treatment of Opioid Dependence 13.2 Chronic exposure to opioids is not life-threatening in adults and neither is withdrawal. It is acute overdose, and the behaviour associated with misuse that cause problems (e.g. polydrug use, injecting and infections, criminality, mixing with alcohol). Although other drugs such as buprenorphine and dihydrocodeine are used, methadone remains the commonest opioid prescribed for the management of heroin misuse. Street heroin is impure and users may lie about the quantities that they take. It is therefore not possible to accurately convert them to methadone. To overcome this, it is common practice when heroin users are admitted to hospital to give a stat dose of methadone orally, supplemented by smaller doses at regular intervals if objective withdrawal symptoms persist. A dose of 40mg methadone in 24 hours should generally not be exceeded on the first day. Naloxone should always be written up when required at the same time in case of accidental overdose (be aware of the possibility of illicit drug taking occurring on the ward). The following day, the methadone dose from the day before can be repeated or the dose adjusted up or down depending upon response. It takes several days to reach steady state drug levels so increase doses with care. Whenever a heroin user enters hospital it is important to contact the local drug dependency team, GP or community pharmacist as soon as possible, so that arrangements can be made for ongoing care after discharge.
In the UK, many psychiatrists and specialists do not exceed a daily dose of methadone of 80mg, although higher doses are becoming more common. It is also very rare for intravenous methadone to be prescribed. Although some users start methadone and then are gradually weaned off, a lot of users are started on methadone and stay on it for many years. This maintenance therapy is a legitimate aim which removes users from the risks associated with injecting heroin (infection, crime etc). For advice on the use of high-dose buprenorphine (Subutex ) as maintenance therapy, or to achieve opioid withdrawal, consult the SPC. As a partial agonist it may block the rewarding effects of heroin which is an advantage; there are also handling advantages for pharmacists as it is not a liquid, and it can be given three times weekly instead of daily (unlicensed). Disadvantages are that the small water-soluble sublingual tablets can be easily injected, and that supervised self-administration is more difficult than with methadone. Buprenorphine s partial agonist action can also trigger withdrawal symptoms at the initiation of treatment if care is not taken, and it may block the actions of opioid analgesics if they are needed. Treatment of Alcohol Dependence Alcohol withdrawal normally starts within 24 hours of the last intake of alcohol. It is not possible to prevent alcohol withdrawal with medication. Sedative drugs such as chlordiazepoxide help to make withdrawal more bearable, but they do not prevent it. When alcohol detoxification is performed in hospital, a high dose of sedative drugs is prescribed initially and this is then gradually reduced usually over a seven day period. Care should be taken to use reduced doses in the elderly in case of excessive CNS depression. Sedatives should NOT be prescribed to alcoholics leaving hospital or as a maintenance therapy, as this serves no purpose and merely encourages dependence on sedatives as well as alcohol. Sedatives and alcohol can also interact to cause dangerous CNS depression. Chronic alcoholism depletes the body of vitamin B1 (thiamine) due to decreased dietary intake, decreased absorption and the inhibition of vitamin activation by alcohol. It is advisable to take every opportunity to replace this in alcoholics, in order to prevent the serious disorders Wernicke s encephalopathy and Korsakoff s psychosis. In those already showing symptoms, very high intravenous doses of vitamin B1 are given (e.g. Pabrinex). For those without symptoms, oral doses of up to 300mg per day can be prescribed for the duration of hospital admission. Questions to Ask an Enquirer When asked about the misuse of drugs, consider the following questions: How certain are you that the amount of drug taken and the frequency of use is correct? Users may lie about the quantities consumed and the purity of street drugs also varies very widely. Has a urine screen been organised? What were the results? Does use of the drug relate to a single exposure, short-term use or a persistent habit? How is the subject taking the drug (e.g. injection, oral)? Is the subject taking other drugs? It may be important to know about other substances (e.g. tobacco, prescribed drugs): some enquirers panic when they hear about an illicit drug, or automatically blame it for all the patient s problems, and don t ask further questions. If the enquirer has used slang terms for drugs that you are not familiar with, ask them to clarify. Many enquiries concern side effects, interactions or use in pregnancy. You should consider the questions posed in the Tutorials on these subjects to guide you in these situations. 13.3
When asked about drug withdrawal in any context, it is essential to know: What is the reason for withdrawal? If for urgent medical reasons, withdrawal may need to be immediate, with the actual withdrawal effects assuming secondary importance. Does the patient agree with the decision to withdraw the drug? Without the patient s co-operation, attempts at withdrawal are not likely to succeed. Has withdrawal been attempted before? How was it done? What happened? Is withdrawal the only option? Have other options been considered if appropriate (e.g. maintenance therapy)? Example Sources to Use in Answering Enquiries Drugs of Abuse by Wills (Pharmaceutical Press 2005) is a great place to start if you are not very familiar with this area. The Department of Health s 2007 Drug Misuse and Dependence Guidelines (also known as the the Orange Guide ) are helpful if you are asked to give advice about the clinical management of patients who misuse drugs. It s available as a hard copy or at www.nta.nhs.uk/uploads/clinical_guidelines_2007.pdf There are useful sections in both The Maudsley Guidelines and the Psychotropic Drug Directory on a range of common scenarios. Toxbase is helpful for a range of substance misuse enquiries including those on legal highs just put the substance you are looking for in the Search box. There are many helpful websites too including the US government s National Institute on Drug Abuse at www.drugabuse.gov/ Helpful UK sites include: DrugScope, an independent centre for expertise on drugs and drugs policy at www.drugscope.org.uk. Click on the Drug Information tab, then Good practice/research and then Treatment for some helpful guidelines. Substance Misuse Management in General Practice which has lots of helpful guidance in their Resource Library at www.smmgp.org.uk/. Talk to Frank which is intended for members of the public at www.talktofrank.com Further Reading It is difficult to recommend further general reading because this subject is too big! Browse through the above sources and become familiar with them, especially the National Institute on Drug Abuse website. Exercises Have a go at the Test Yourself! questions on the next page. Read through the example enquiry on page 13.7. Tackle the real enquiries with your tutor on page 13.8. 13.4
Test Yourself! 1. A patient who used to take 10mg nitrazepam at night, now asks for the dose to be increased to 15mg at night because the tablets are no longer working. What is happening here? 2. If asked about methods of drug withdrawal, why do you think the patient s co-operation in the process is a key to success? 3. What side effects might you expect to be associated with drugs described as CNS depressants? 4. What is the brand name of the intravenous product containing vitamin B1 used to treat deficiency in patients with alcoholism? How would you find out the dose to use in acute severe deficiency? What is it? 5. Is it true that withdrawal reactions only last as long as it takes for the drug to leave the body? 13.5
6. Give three or four examples of prescription medicines that can cause withdrawal reactions. 7. What would you do if a hospital doctor phoned and asked for advice on how to manage a suspected heroin overdose? 8. Why do you think that injecting or inhaling drugs with dependence potential is more likely to cause dependence than taking them by mouth? 9. What is the difference between drug misuse and drug dependence? 10. Why do you think that successfully maintaining a heroin user on prescribed methadone for life would be seen as a sign of treatment success? 13.6
Example Enquiry The following e-mail was sent in response to an enquiry from an outreach oncology nurse. He wanted to establish which antidepressant(s) would be suitable in a patient using cannabis oil. 13.7
Real Enquiries This section helps you to think about the enquiry answering process. Below are given the details of three real enquiries, as received by a regional MI centre. Decide with your tutor which of these enquiries to do. Then for each one describe: (a) Any further questions you would like to ask the enquirer. (b) The top sources that you would use to answer the enquiry. Your tutor will go through these with you when you have finished. If you like, research a full answer using the MiDatabank Trainer on MiCAL to document it, but discuss this with your tutor first. 1. Interactions involving cocaine A psychiatry registrar contacts you. She would like to know if it is acceptable to prescribe atypical antipsychotics to a patient who is a cocaine user. He has become very violent after a recent stroke. Further questions for enquirer Sources to use 13.8
2. Abuse of prescription medicine A GP asks you if procyclidine can be abused. He suspects a patient who was originally prescribed it to treat Parkinsonian symptoms. Further questions for enquirer Sources to use 3. Withdrawal of anabolic steroids A police surgeon rings you to find out more about anabolic steroids. He needs to know if they can be stopped suddenly in a man who is currently in police cells. Further questions for enquirer Sources to use 13.9
Notes 13.10