– a group which includes morphine, codeine, pethidine and methadone. It is a powerful analgesic and cough suppressant, but its capacity to produce euphoria rapidly induces DEPENDENCE. Popular with addicts, its mostly pleasant effects soon produce TOLERANCE; the need to inject the drug, with associated risks of HIV infection, has affected its use by addicts. Withdrawal symptoms include restlessness, insomnia, muscle cramps, vomiting and diarrhoea; signs include dilated pupils, raised pulse rate, and disturbed temperature control. Although rarely life-threatening, the effects of withdrawal may cause great distress, and for this reason methadone, which has a slower and less severe withdrawal syndrome, is commonly used when weaning addicts o? heroin. Legally still available to doctors in the UK, heroin is normally only used in patients with severe pain, or to comfort the dying.... heroin
The importation into Britain of opium is strictly regulated under the Dangerous Drugs Acts. Similar regulations govern the sale and distribution of any preparation of morphine or diamorphine (heroin) stronger than 1 part in
500. (See DEPENDENCE.)
Action The action of opium varies considerably, according to the source of the drug and the preparation used.
In small doses, opium produces a state of gentle excitement, the person ?nding their imagination more vivid, their thoughts more brilliant, and their power of expression greater than usual. This stage lasts for some hours, and is succeeded by languor. In medicinal doses this stage of excitement is short and is followed by deep sleep. When potentially poisonous doses are taken, sleep comes on quickly, and passes into coma and death (see OPIOID POISONING). The habitual use of opium produces great TOLERANCE, so that opium users require to take large quantities daily before experiencing its pleasurable effects. The need for opium also confers tolerance, so that people suffering great pain may take, with apparently little e?ect beyond dulling the pain, quantities which at another time would be dangerous.... opium
The Misuse of Drugs Regulations 1985 de?ne the classes of person authorised to supply and possess controlled drugs, and lay down the conditions under which these activities may be carried out. In the Regulations, drugs are divided into ?ve schedules specifying the requirements for supply, possession, prescribing and record-keeping. Schedule I contains drugs which are not used as medicines. Schedules II and III contain drugs which are subject to the prescription requirements of the Act (see below). They are distinguished in the British National Formulary (BNF) by the symbol CD and they include morphine, diamorphine (heroin), other opioid analgesics, barbiturates, amphetamines, cocaine and diethylpropion. Schedules IV and V contain drugs such as the benzodiazepines which are subject to minimal control. A full list of the drugs in each schedule can be found in the BNF.
Prescriptions for drugs in schedules II and III must be signed and dated by the prescriber, who must give his or her address. The prescription must be in the prescriber’s own handwriting and provide the name and address of the patient and the total quantity of the preparation in both words and ?gures. The pharmacist is not allowed to dispense a controlled drug unless all the information required by law is given on the prescription.
Until 1997 the Misuse of Drugs (Noti?cation and Supply of Addicts) Regulations 1973 governed the noti?cation of addicts. This was required in respect of the following commonly used drugs: cocaine, dextromoramide, diamorphine, dipipanone, hydrocodeine, hydromorphone, levorphanol, methadone, morphine, opium, oxycodone, pethidine, phenazocine and piritranide.
In 1997 the Misuse of Drugs (Supply to Addicts) Regulations 1997 revoked the 1973 requirement for noti?cation. Doctors are now expected to report (on a standard form) cases of drug misuse to their local Drug Misuse Database (DMD). Noti?cation by the doctor should be made when a patient ?rst presents with a drug problem or when he or she visits again after a gap of six months or more. All types of misuse should be reported: this includes opioids, benzodiazepines and central nervous system stimulants. The data in the DMD are anonymised, which means that doctors cannot check on possible multiple prescribing for drug addicts.
The 1997 Regulations restrict the prescribing of diamorphine (heroin), Diconal® (a morphine-based drug) or cocaine to medical practitioners holding a special licence issued by the Home Secretary.
Fuller details about the prescription of controlled drugs are in the British National Formulary, updated twice a year, and available on the Internet (see www.bnf.org).... controlled drugs
The dependence that most concerns modern society is one in which individuals become dependent on or addicted to certain substances such as alcohol, drugs, tobacco (nicotine), caffeine and solvents. This is often called substance abuse. Some people become addicted to certain foods or activities: examples of the latter include gambling, computer games and use of the Internet.
The 28th report of the World Health Organisation Expert Committee on Drug Dependence in 1993 de?ned drug dependence as: ‘A cluster of physiological, behavioural and cognitive phenomena of variable intensity, in which the use of a psychoactive drug (or drugs) takes on a high priority. The necessary descriptive characteristics are preoccupation with a desire to obtain and take the drug and persistent drug-seeking behaviour. Psychological dependence occurs when the substance abuser craves the drug’s desirable effects. Physical dependence occurs when the user has to continue taking the drug to avoid distressing withdrawal or abstinence symptoms. Thus, determinants and the problematic consequences of drug dependence may be biological, psychological or social and usually interact.’
Di?erent drugs cause di?erent rates of dependence: TOBACCO is the most common substance of addiction; HEROIN and COCAINE cause high rates of addiction; whereas ALCOHOL is much lower, and CANNABIS lower again. Smoking in the western world reached a peak after World War II with almost 80 per cent of the male population smoking. The reports on the link between smoking and cancer in the early 1960s resulted in a decline that has continued so that only around a quarter of the adult populations of the UK and USA smokes. Globally, tobacco consumption continues to grow, particularly in the developing world with multinational tobacco companies marketing their products aggressively.
Accurate ?gures for illegal drug-taking are hard to obtain, but probably approximately 4 per cent of the population is dependent on alcohol and 2 per cent on other drugs, both legal and illegal, at any one time in western countries.
How does dependence occur? More than 40 distinct theories or models of drug misuse have been put forward. One is that the individual consumes drugs to cope with personal problems or diffculties in relations with others. The other main model emphasises environmental in?uences such as drug availability, environmental pressures to consume drugs, and sociocultural in?uences such as peer pressure.
By contrast to these models of why people misuse drugs, models of compulsive drug use – where individuals have a compulsive addiction
– have been amenable to testing in the laboratory. Studies at cellular and nerve-receptor levels are attempting to identify mechanisms of tolerance and dependence for several substances. Classical behaviour theory is a key model for understanding drug dependence. This and current laboratory studies are being used to explain the reinforcing nature of dependent substances and are helping to provide an explanatory framework for dependence. Drug consumption is a learned form of behaviour. Numerous investigators have used conditioning theories to study why people misuse drugs. Laboratory studies are now locating the ‘reward pathways’ in the brain for opiates and stimulants where positive reinforcing mechanisms involve particular sectors of the brain. There is a consensus among experts in addiction that addictive behaviour is amenable to e?ective treatment, and that the extent to which an addict complies with treatment makes it possible to predict a positive outcome. But there is a long way to go before the mechanisms of drug addiction are properly understood or ways of treating it generally agreed.
Effects of drugs Cannabis, derived from the plant Cannabis sativa, is a widely used recreational drug. Its two main forms are marijuana, which comes from the dried leaves, and hashish which comes from the resin. Cannabis may be used in food and drink but is usually smoked in cigarettes to induce relaxation and a feeling of well-being. Heavy use can cause apathy and vagueness and may even cause psychosis. Whether or not cannabis leads people to using harder drugs is arguable, and a national debate is underway on whether its use should be legalised for medicinal use. Cannabis may alleviate the symptoms of some disorders – for example, MULTIPLE SCLEROSIS (MS) – and there are calls to allow the substance to be classi?ed as a prescribable drug.
About one in ten of Britain’s teenagers misuses volatile substances such as toluene at some time, but only about one in 40 does so regularly. These substances are given o? by certain glues, solvents, varnishes, and liquid fuels, all of which can be bought cheaply in shops, although their sale to children under 16 is illegal. They are often inhaled from plastic bags held over the nose and mouth. Central-nervous-system excitation, with euphoria and disinhibition, is followed by depression and lethargy. Unpleasant effects include facial rash, nausea and vomiting, tremor, dizziness, and clumsiness. Death from COMA and acute cardiac toxicity is a serious risk. Chronic heavy use can cause peripheral neuropathy and irreversible cerebellar damage. (See SOLVENT ABUSE (MISUSE).)
The hallucinogenic or psychedelic drugs include LYSERGIC ACID DIETHYLAMIDE (LSD) or acid, magic mushrooms, ecstasy (MDMA), and phencyclidine (PCP or ‘angel’ dust, mainly used in the USA). These drugs have no medicinal uses. Taken by mouth, they produce vivid ‘trips’, with heightened emotions and perceptions and sometimes with hallucinations. They are not physically addictive but can cause nightmarish bad trips during use and ?ashbacks (vivid reruns of trips) after use, and can probably trigger psychosis and even death, especially if drugs are mixed or taken with alcohol.
Stimulant drugs such as amphetamine and cocaine act like adrenaline and speed up the central nervous system, making the user feel con?dent, energetic, and powerful for several hours. They can also cause severe insomnia, anxiety, paranoia, psychosis, and even sudden death due to convulsions or tachycardia. Depression may occur on withdrawal of these drugs, and in some users this is su?ciently deterrent to cause psychological dependence. Amphetamine (‘speed’) is mainly synthesised illegally and may be eaten, sni?ed, or injected. Related drugs, such as dexamphetamine sulphate (Dexedrine), are prescribed pills that enter the black market. ECSTASY is another amphetamine derivative that has become a popular recreational drug; it may have fatal allergic effects. Cocaine and related drugs are used in medicine as local anaesthetics. Illegal supplies of cocaine (‘snow’ or ‘ice’) and its derivative, ‘crack’, come mainly from South America, where they are made from the plant Erythroxylon coca. Cocaine is usually sni?ed (‘snorted’) or rubbed into the gums; crack is burnt and inhaled.
Opiate drugs are derived from the opium poppy, Papaver somniferum. They are described as narcotic because they induce sleep. Their main medical use is as potent oral or injectable analgesics such as MORPHINE, DIAMORPHINE, PETHIDINE HYDROCHLORIDE, and CODEINE. The commonest illegal opiate is heroin, a powdered form of diamorphine that may be smoked, sni?ed, or injected to induce euphoria and drowsiness. Regular opiate misuse leads to tolerance (the need to take ever larger doses to achieve the same e?ect) and marked dependence. A less addictive oral opiate, METHADONE HYDROCHLORIDE, can be prescribed as a substitute that is easier to withdraw.
Some 75,000–150,000 Britons now misuse opiates and other drugs intravenously, and pose a huge public-health problem because injections with shared dirty needles can carry the blood-borne viruses that cause AIDS/HIV and HEPATITIS B. Many clinics now operate schemes to exchange old needles for clean ones, free of charge. Many addicts are often socially disruptive.
For help and advice see APPENDIX 2: ADDRESSES: SOURCES OF INFORMATION, ADVICE, SUPPORT AND SELF-HELP – National Dugs Helpline.
(See ALCOHOL and TOBACCO for detailed entries on those subjects.)... dependence
Arrhythmias An abnormal rate or rhythm of the heartbeat. The reason is a disturbance in the electrical impulses within the heart. Sometimes a person may have an occasional irregular heartbeat: this is called an ECTOPIC beat (or an extrasystole) and does not necessarily mean that an abnormality exists. There are two main types of arrhythmia: bradycardias, where the rate is slow – fewer than 60 beats a minute and sometimes so slow and unpredictable (heartblock) as to cause blackouts or heart failure; and tachycardia, where the rate is fast – more than 100 beats a minute. A common cause of arrhythmia is coronary artery disease, when vessels carrying blood to the heart are narrowed by fatty deposits (ATHEROMA), thus reducing the blood supply and damaging the heart tissue. This condition often causes myocardial infarction after which arrhythmias are quite common and may need correcting by DEFIBRILLATION (application of a short electric shock to the heart). Some tachycardias result from a defect in the electrical conduction system of the heart that is commonly congenital. Various drugs can be used to treat arrhythmias (see ANTIARRHYTHMIC DRUGS). If attacks constantly recur, the arrhythmia may be corrected by electrical removal of dead or diseased tissue that is the cause of the disorder. Heartblock is most e?ectively treated with an arti?cial CARDIAC PACEMAKER, a battery-activated control unit implanted in the chest.
Cardiomyopathy Any disease of the heart muscle that results in weakening of its contractions. The consequence is a fall in the e?ciency of the circulation of blood through the lungs and remainder of the body structures. The myopathy may be due to infection, disordered metabolism, nutritional excess or de?ciency, toxic agents, autoimmune processes, degeneration, or inheritance. Often, however, the cause is not identi?ed. Cardiomyopathies are less common than other types of heart diseases, and the incidence of di?erent types of myopathy (see below) is not known because patients or doctors are sometimes unaware of the presence of the condition.
The three recognised groups of cardiomyopathies are hypertrophic, dilated and restrictive.
•Hypertrophic myopathy, a familial condition, is characterised by great enlargement of the muscle of the heart ventricles. This reduces the muscle’s e?ciency, the ventricles fail to relax properly and do not ?ll suf?ciently during DIASTOLE.
In the dilated type of cardiomyopathy, both ventricles overdilate, impairing the e?ciency of contraction and causing congestion of the lungs.
In the restrictive variety, proper ?lling of the ventricles does not occur because the muscle walls are less elastic than normal. The result is raised pressure in the two atria (upper cavities) of the heart: these dilate and develop FIBRILLATION. Diagnosis can be di?cult and treatment is symptomatic, with a poor prognosis. In suitable patients, heart TRANSPLANTATION may be considered. Disorders of the heart muscle may also be
caused by poisoning – for example, heavy consumption of alcohol. Symptoms include tiredness, palpitations (quicker and sometimes irregular heartbeat), chest pain, di?culty in breathing, and swelling of the legs and hands due to accumulation of ?uid (OEDEMA). The heart is enlarged (as shown on chest X-ray) and ECHOCARDIOGRAPHY shows thickening of the heart muscle. A BIOPSY of heart muscle will show abnormalities in the cells of the heart muscle.
Where the cause of cardiomyopathy is unknown, as is the case with most patients, treatment is symptomatic using DIURETICS to control heart failure and drugs such as DIGOXIN to return the heart rhythm to normal. Patients should stop drinking alcohol. If, as often happens, the patient’s condition slowly deteriorates, heart transplantation should be considered.
Congenital heart disease accounts for 1–2 per cent of all cases of organic heart disease. It may be genetically determined and so inherited; present at birth for no obvious reason; or, in rare cases, related to RUBELLA in the mother. The most common forms are holes in the heart (atrial septal defect, ventricular septal defect – see SEPTAL DEFECT), a patent DUCTUS ARTERIOSUS, and COARCTATION OF THE AORTA. Many complex forms also exist and can be diagnosed in the womb by fetal echocardiography which can lead to elective termination of pregnancy. Surgery to correct many of these abnormalities is feasible, even for the most severe abnormalities, but may only be palliative giving rise to major diffculties of management as the children become older. Heart transplantation is now increasingly employed for the uncorrectable lesions.
Coronary artery disease Also known as ischaemic heart disease, this is a common cause of symptoms and death in the adult population. It may present for the ?rst time as sudden death, but more usually causes ANGINA PECTORIS, myocardial infarction (heart attack) or heart failure. It can also lead to a disturbance of heart rhythm. Factors associated with an increased risk of developing coronary artery disease include diabetes, cigarette smoking, high blood pressure, obesity, and a raised concentration of cholesterol in the blood. Older males are most affected.
Coronary thrombosis or acute myocardial infarction is the acute, dramatic manifestation of coronary-artery ischaemic heart disease – one of the major killing diseases of western civilisation. In 1999, ischaemic heart disease was responsible for about 115,000 deaths in England and Wales, compared with 153,000 deaths in 1988. In 1999 more than 55,600 people died of coronary thrombosis. The underlying cause is disease of the coronary arteries which carry the blood supply to the heart muscle (or myocardium). This results in narrowing of the arteries until ?nally they are unable to transport su?cient blood for the myocardium to function e?ciently. One of three things may happen. If the narrowing of the coronary arteries occurs gradually, then the individual concerned will develop either angina pectoris or signs of a failing heart: irregular rhythm, breathlessness, CYANOSIS and oedema.
If the narrowing occurs suddenly or leads to complete blockage (occlusion) of a major branch of one of the coronary arteries, then the victim collapses with acute pain and distress. This is the condition commonly referred to as a coronary thrombosis because it is usually due to the affected artery suddenly becoming completely blocked by THROMBOSIS. More correctly, it should be described as coronary occlusion, because the ?nal occluding factor need not necessarily be thrombosis.
Causes The precise cause is not known, but a wide range of factors play a part in inducing coronary artery disease. Heredity is an important factor. The condition is more common in men than in women; it is also more common in those in sedentary occupations than in those who lead a more physically active life, and more likely to occur in those with high blood pressure than in those with normal blood pressure (see HYPERTENSION). Obesity is a contributory factor. The disease is more common among smokers than non-smokers; it is also often associated with a high level of CHOLESTEROL in the blood, which in turn has been linked with an excessive consumption of animal, as opposed to vegetable, fats. In this connection the important factors seem to be the saturated fatty acids (low-density and very low-density lipoproteins [LDLs and VLDLs] – see CHOLESTEROL) of animal fats which would appear to be more likely to lead to a high level of cholesterol in the blood than the unsaturated fatty acids of vegetable fats. As more research on the subject is carried out, the arguments continue about the relative in?uence of the di?erent factors. (For advice on prevention of the disease, see APPENDIX 2: ADDRESSES: SOURCES OF INFORMATION, ADVICE, SUPPORT AND SELFHELP.)
Symptoms The presenting symptom is the sudden onset, often at rest, of acute, agonising pain in the front of the chest. This rapidly radiates all over the front of the chest and often down over the abdomen. The pain is frequently accompanied by nausea and vomiting, so that suspicion may be aroused of some acute abdominal condition such as biliary colic (see GALLBLADDER, DISEASES OF) or a perforated PEPTIC ULCER. The victim soon goes into SHOCK, with a pale, cold, sweating skin, rapid pulse and dif?culty in breathing. There is usually some rise in temperature.
Treatment is immediate relief of the pain by injections of diamorphine. Thrombolytic drugs should be given as soon as possible (‘rapid door to needle time’) and ARRHYTHMIA corrected. OXYGEN is essential and oral ASPIRIN is valuable. Treatment within the ?rst hour makes a great di?erence to recovery. Subsequent treatment includes the continued administration of drugs to relieve the pain; the administration of ANTIARRHYTHMIC DRUGS that may be necessary to deal with the heart failure that commonly develops, and the irregular action of the heart that quite often develops; and the continued administration of oxygen. Patients are usually admitted to coronary care units, where they receive constant supervision. Such units maintain an emergency, skilled, round-the-clock sta? of doctors and nurses, as well as all the necessary resuscitation facilities that may be required.
The outcome varies considerably. The ?rst (golden) hour is when the patient is at greatest risk of death: if he or she is treated, then there is a 50 per cent reduction in mortality compared with waiting until hospital admission. As each day passes the prognosis improves with a ?rst coronary thrombosis, provided that the patient does not have a high blood pressure and is not overweight. Following recovery, there should be a gradual return to work, care being taken to avoid any increase in weight, unnecessary stress and strain, and to observe moderation in all things. Smoking must stop. In uncomplicated cases patients get up and about as soon as possible, most being in hospital for a week to ten days and back at work in three months or sooner.
Valvular heart disease primarily affects the mitral and aortic valves which can become narrowed (stenosis) or leaking (incompetence). Pulmonary valve problems are usually congenital (stenosis) and the tricuspid valve is sometimes involved when rheumatic heart disease primarily affects the mitral or aortic valves. RHEUMATIC FEVER, usually in childhood, remains a common cause of chronic valvular heart disease causing stenosis, incompetence or both of the aortic and mitral valves, but each valve has other separate causes for malfunction.
Aortic valve disease is more common with increasing age. When the valve is narrowed, the heart hypertrophies and may later fail. Symptoms of angina or breathlessness are common and dizziness or blackouts (syncope) also occur. Replacing the valve is a very e?ective treatment, even with advancing age. Aortic stenosis may be caused by degeneration (senile calci?c), by the inheritance of two valvular leaflets instead of the usual three (bicuspid valve), or by rheumatic fever. Aortic incompetence again leads to hypertrophy, but dilatation is more common as blood leaks back into the ventricle. Breathlessness is the more common complaint. The causes are the same as stenosis but also include in?ammatory conditions such as SYPHILIS or ANKYLOSING SPONDYLITIS and other disorders of connective tissue. The valve may also leak if the aorta dilates, stretching the valve ring as with HYPERTENSION, aortic ANEURYSM and MARFAN’S SYNDROME – an inherited disorder of connective tissue that causes heart defects. Infection (endocarditis) can worsen acutely or chronically destroy the valve and sometimes lead to abnormal outgrowths on the valve (vegetations) which may break free and cause devastating damage such as a stroke or blocked circulation to the bowel or leg.
Mitral valve disease leading to stenosis is rheumatic in origin. Mitral incompetence may be rheumatic but in the absence of stenosis can be due to ISCHAEMIA, INFARCTION, in?ammation, infection and a congenital weakness (prolapse). The valve may also leak if stretched by a dilating ventricle (functional incompetence). Infection (endocarditis) may affect the valve in a similar way to aortic disease. Mitral symptoms are predominantly breathlessness which may lead to wheezing or waking at night breathless and needing to sit up or stand for relief. They are made worse when the heart rhythm changes (atrial ?brillation) which is frequent as the disease becomes more severe. This leads to a loss of e?ciency of up to 25 per cent and a predisposition to clot formation as blood stagnates rather than leaves the heart e?ciently. Mitral incompetence may remain mild and be of no trouble for many years, but infection must be guarded against (endocarditis prophylaxis).
Endocarditis is an infection of the heart which may acutely destroy a valve or may lead to chronic destruction. Bacteria settle usually on a mild lesion. Antibiotics taken at vulnerable times can prevent this (antibiotic prophylaxis) – for example, before tooth extraction. If established, lengthy intravenous antibiotic therapy is needed and surgery is often necessary. The mortality is 30 per cent but may be higher if the infection settles on a replaced valve (prosthetic endocarditis). Complications include heart failure, shock, embolisation (generation of small clots in the blood), and cerebral (mental) confusion.
PERICARDITIS is an in?ammation of the sac covering the outside of the heart. The sac becomes roughened and pain occurs as the heart and sac rub together. This is heard by stethoscope as a scratching noise (pericardial rub). Fever is often present and a virus the main cause. It may also occur with rheumatic fever, kidney failure, TUBERCULOSIS or from an adjacent lung problem such as PNEUMONIA or cancer. The in?ammation may cause ?uid to accumulate between the sac and the heart (e?usion) which may compress the heart causing a fall in blood pressure, a weak pulse and circulatory failure (tamponade). This can be relieved by aspirating the ?uid. The treatment is then directed at the underlying cause.... heart, diseases of
Misuse of Drugs Act 1971 This legislation forbids activities relating to the manufacture, sale and possession of particular (controlled) drugs. These are classi?ed into three grades according to their dangers if misused. Any o?ences concerning class A drugs, potentially the most damaging when abused, carry the toughest penalties, while classes B and C attract lesser penalties if abused.
Class A includes: cocaine, dextromoramide, diamorphine (heroin), lysergic acid (LSD), methadone, morphine, opium, pethidine, phencyclidine acid and injectable preparations of class B drugs.
Class B includes: oral amphetamines, barbiturates, codeine, glutethimide, marijuana (cannabis), pentazocine and pholcodine.
Class C includes: drugs related to the amphetamines, anabolic and androgenic steroids, many benzodiazepines, buprenorphine, diethyl propion, human chorionic gonadotrophin (HCG), mazindol, meprobamate, pemoline, phenbuterol, and somatropin.
Misuse of Drugs Regulations 1985 These regulations de?ne those people who are authorised in their professional capacity to supply and possess controlled drugs. They also describe the requirements for legally undertaking these activities, such as storage of the drugs and limits on their prescription.
Drugs are divided into ?ve schedules and some examples follow.
I: Almost all are prohibited except in accordance with Home O?ce authority: marijuana (cannabis), LSD.
II: High potential for abuse but have
accepted medical uses: amphetamines, cocaine.
III: Lower potential for abuse: barbiturates, meprobamate, temazepam.
IV: Lower potential for abuse than I to III. Minimal control: benzodiazepines.
V: Low potential for abuse: generally compound preparations containing small amounts of opioids: kaolin and morphine (antidiarrhoeal medicine), codeine linctus (cough suppressant).
(See also CONTROLLED DRUGS.)... misuse of drugs
There are three main categories of licensed medicinal product. Drugs in small quantities can, if they are perceived to be safe, be licensed for general sale (GSL – general sales list), and may then be sold in any retail shop. P (pharmacy-only) medicines can be sold from a registered pharmacy by or under the supervision of a pharmacist (see PHARMACISTS); no prescription is needed. P and GSL medicines are together known as OTCs – that is, ‘over-thecounter medicines’. POM (prescription-only medicines) can only be obtained from a registered pharmacy on the prescription of a doctor or dentist. As more information is gathered on the safety of drugs, and more emphasis put on individual responsibility for health, there is a trend towards allowing drugs that were once POM to be more widely available as P medicines. Examples include HYDROCORTISONE 1 per cent cream for skin rashes, CIMETIDINE for indigestion, and ACICLOVIR for cold sores. Care is needed to avoid taking a P medicine that might alter the actions of another medicine taken with it, or that might be unsuitable for other reasons. Patients should read the patient-information lea?et, and seek the pharmacist’s advice if they have any doubt about the information. They should tell their pharmacist or doctor if the medicine results in any unexpected effects.
Potentially dangerous drugs are preparations referred to under the Misuse of Drugs Act 1971 and subsequent regulations approved in 1985. Described as CONTROLLED DRUGS, these include such preparations as COCAINE, MORPHINE, DIAMORPHINE, LSD (see LYSERGIC ACID
DIETHYLAMIDE (LSD)), PETHIDINE HYDROCHLORIDE, AMPHETAMINES, BARBITURATES and most BENZODIAZEPINES.
Naming of drugs A European Community Directive (92/27/EEC) requires the use of the Recommended International Non-proprietary Name (rINN) for medicinal substances. For most of these the British Approved Name (BAN) and rINN were identical; where the two were di?erent, the BAN has been modi?ed in line with the rINN. Doctors and other authorised subscribers are advised to write titles of drugs and preparations in full because uno?cial abbreviations may be misinterpreted. Where a drug or preparation has a non-proprietary (generic) title, this should be used in prescribing unless there is a genuine problem over the bioavailability properties of a proprietary drug and its generic equivalent.
Where proprietary – commercially registered
– names exist, they may in general be used only for products supplied by the trademark owners. Countries outside the European Union have their own regulations for the naming of medicines.
Methods of administration The ways in which drugs are given are increasingly ingenious. Most are still given by mouth; some oral preparations (‘slow release’ or ‘controlled release’ preparations) are designed to release their contents slowly into the gut, to maintain the action of the drug.
Buccal preparations are allowed to dissolve in the mouth, and sublingual ones are dissolved under the tongue. The other end of the gastrointestinal tract can also absorb drugs: suppositories inserted in the rectum can be used for their local actions – for example, as laxatives – or to allow absorption when taking the drug by mouth is di?cult or impossible – for example, during a convulsion, or when vomiting.
Small amounts of drug can be absorbed through the intact skin, and for very potent drugs like OESTROGENS (female sex hormones) or the anti-anginal drug GLYCERYL TRINITRATE, a drug-releasing ‘patch’ can be used. Drugs can be inhaled into the lungs as a ?ne powder to treat or prevent ASTHMA attacks. They can also be dispersed (‘nebulised’) as a ?ne mist which can be administered with compressed air or oxygen. Spraying a drug into the nostril, so that it can be absorbed through the lining of the nose into the bloodstream, can avoid destruction of the drug in the stomach. This route is used for a small number of drugs like antidiuretic hormone (see VASOPRESSIN).
Injection remains an important route of administering drugs both locally (for example, into joints or into the eyeball), and into the bloodstream. For this latter purpose, drugs can be given under the skin – that is, subcutaneously (s.c. – also called hypodermic injection); into muscle – intramuscularly (i.m.); or into a vein – intravenously (i.v.). Oily or crystalline preparations of drugs injected subcutaneously form a ‘depot’ from which they are absorbed only slowly into the blood. The action of drugs such as TESTOSTERONE and INSULIN can be prolonged by using such preparations, which also allow contraceptive ‘implants’ that work for some months (see CONTRACEPTION).... medicines
Opioids, also knows as narcotic drugs, may be abused for their euphoric effects; abuse may cause tolerance (the need for greater amounts of a drug to get the same effect), and physical and psychological drug dependence.
Commonly used opioids include codeine, diamorphine, morphine, and pethidine.... opioid
Surgery may be most common, and is often the only treatment, for some gastrointestinal tumours, soft-tissue tumours, gynaecological tumours and advanced cancers of the head and neck.
Radiotherapy uses ionising radiation to kill tumour cells. Radiation is by naturally occurring isotopes (see ISOTOPE) or arti?cially produced X-RAYS. Germ-cell tumours (see SEMINOMA; TERATOMA) and malignant lymphomas (see LYMPHOMA) appear to be particularly sensitive to irradiation, and many head and neck tumours, gynaecological cancers, and localised cancers of the PROSTATE GLAND and URINARY BLADDER are curable with radiotherapy. It is also a valuable means of reducing pain from bone metastases (see METASTASIS). Unpleasant side-effects are common: chie?y lethargy, loss of appetite and dry, itchy skin symptoms.
Chemotherapy is also an important treatment in germ-cell tumours (see above); in some forms of LEUKAEMIA and lymphoma; in ovarian cancer (following surgery – see OVARIES, DISEASES OF); and in small-cell lung cancer (although most patients die within 18 months – see LUNGS, DISEASES OF). It is also used in some breast cancers (see BREASTS, DISEASES OF); advanced myeloma (see MYELOMATOSIS); sarcomas (see under CANCER); and some childhood cancers (such as WILMS’ TUMOUR).
More than 20 substances are in common use, the major classes being ALKYLATING AGENTS (e.g. cyclophosphamide, chlorambucil, busul fan); ANTIMETABOLITES (e.g. methotrexate); VINCA ALKALOIDS (e.g. vincristine, vinblastine); and antitumour ANTIBIOTICS (e.g. actinomycin D). Choice of agent and the appropriate regimen requires expert guidance. Common side-effects include nausea and vomiting, bone-marrow suppression and ALOPECIA, with each substance having its own spectrum of unwanted effects.
Good doctor-patient communication, with the sharing of information and bringing the patient into the decision-making process, is vital even if time-consuming and exhausting.
Equally imortant treatment is PALLIATIVE, for example to ensure e?ective pain or nausea control. Common sources of pain in cancer may involve bone, nerve compression, soft tissue, visceral, myofascial, constipation, muscle spasm, low-back pain, joint pain (e.g. capsulitis) and chronic post-operative pain. Patients may be suffering from more than one pain, all of which should be identi?ed. The aim should be to eliminate pain.
There are three rungs of the analgesic ladder; if one rung fails, the next one should be tried:
(1) non-opioid drugs – for example, aspirin, PARACETAMOL, NON-STEROIDAL ANTIINFLAMMATORY DRUGS (NSAIDS); (2) weak opioids – for example, CODEINE, DIHYDROCODEINE, dextropropoxyphene; (3) strong opioids
– for example, MORPHINE, DIAMORPHINE, buprenorphine. Oral treatment is always preferable, unless prevented by severe vomiting. (See also CANCER; ONCOLOGIST; PAIN; PALLIATIVE CARE.)... oncology
– an early graded return to activity gives the best long-term results, but doing too much too soon runs the risk of exacerbating the original injury.
Chronic (overuse) injuries affecting the bones (see BONE), tendons (see TENDON) or BURSAE of the JOINTS are common in many sports. Examples include chronic INFLAMMATION of the common extensor tendon where it
attaches to the later EPICONDYLE of the humerus – common in throwers and racquet sportspeople – and stress fractures of the TIBIA or METATARSAL BONES of the foot in runners. After an initial period of rest, management often involves coaching that enables the athlete to perform the repetitive movement in a less injury-susceptible manner.
Exercise physiology is the science of measuring athletic performance and physical ?tness for exercise. This knowledge is applied to devising and supervising training regimens based on scienti?c principles. Physical ?tness depends upon the rate at which the body can deliver oxygen to the muscles, known as the VO2max, which is technically di?cult to measure. The PULSE rate during and after a bout of exercise serves as a good proxy of this measurement.
Regulation of sport Sports medicine’s role is to minimise hazards for participants by, for example, framing rule-changes which forbid collapsing the scrum, which has reduced the risk of neck injury in rugby; and in the detection of the use of drugs taken to enhance athletic performance. Such attempts to gain an edge in competition undermine the sporting ideal and are banned by leading sports regulatory bodies. The Olympic Movement Anti-Doping Code lists prohibited substances and methods that could be used to enhance performance. These include some prohibited in certain circumstances as well as those completely banned. The latter include:
stimulants such as AMPHETAMINES, bromantan, ca?eine, carphedon, COCAINE, EPHEDRINE and certain beta-2 agonists.
NARCOTICS such as DIAMORPHINE (heroin), MORPHINE, METHADONE HYDROCHLORIDE and PETHIDINE HYDROCHLORIDE.
ANABOLIC STEROIDS such as methandione, NANDROLONE, stanazol, TESTOSTERONE, clenbuterol, androstenedone and certain beta-2 agonists.
peptide HORMONES, mimetics and analogues such as GROWTH HORMONE, CORTICOTROPHIN, CHORIONIC GONADOTROPHIC HORMONE, pituitary and synthetic GONADOTROPHINS, ERYTHROPOIETIN and INSULIN. (The list produced above is not comprehen
sive: full details are available from the governing bodies of relevant sports.) Among banned methods are blood doping (pre-competition administration of an athlete’s own previously provided and stored blood), administration of arti?cial oxygen carriers or plasma expanders. Also forbidden is any pharmacological, chemical or physical manipulation to affect the results of authorised testing.
Drug use can be detected by analysis of the URINE, but testing only at the time of competition is unlikely to detect drug use designed to enhance early-season training; hence random testing of competitive athletes is also used.
The increasing professionalism and competitiveness (among amateurs and juveniles as well as professionals) in sports sometimes results in pressures on participants to get ?t quickly after injury or illness. This can lead to
players returning to their activity before they are properly ?t – sometimes by using physical or pharmaceutical aids. This practice can adversely affect their long-term physical capabilities and perhaps their general health.... sports medicine
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