Basic Principles of Drug Abuse, Dependency (Addiction), and the Classification of Common Drugs of Abuse

Transcription

1 PhClrmCl~Q~ TEL. (902) I I' ft. Consultants in Pharmacology and Toxicology FAX. (902) INCORPORATED '---- Professional Services in: Education, Forensic, Environmental, Workplace, Addiction and SAFE DRIVER Program UNIT 7,101 ILSLEY AVENUE DARTMOUTH, NOVA SCOTIA B3B 1S8 P.O. BOX 3506, D.E.P.S. DARTMOUTH, N.S. CANADA B2W 5G4 Basic Principles of Drug Abuse, Dependency (Addiction), and the Classification of Common Drugs of Abuse By Greg Johnstone, M.Sc. President, PharmaTox Inc. (This article is taken from a publication (1994), entitled "Community Education Guide For Pharmacists", written by Greg Johnstone) PART ONE Understanding the Development of Addiction and the Associated Pharmacological Principles PART TWO CLASSIFICATION OF DRUGS OF ABUSE AND DEPENDENCE

2 2 Basic Principles of Drug Abuse, Dependency (Addiction), and the Classification of Common Drugs of Abuse PART ONE Understanding the Development of Addiction and the Associated Pharmacological Principles Knowledge in the field of drug dependency has developed some fundamental insights which have an application in many fields. In particular those who practice in the the field of law are becoming more aware of the complex ramifications of the ever increasing number of drugs and chemicals affecting health and behavior. The following principles and concepts form the foundation of modern thinking about drug dependency and addictions. A solid understanding of these principles will assist the professional in becoming more effective at sorting out relevant drug related aspects of a given legal matter. 1. Predictable Course of Drug Dependencv Drug abuse and addiction follows a predictable pattern going from experimentation, social/recreational use, problematic use or abuse, to compulsive and addictive use. Along this continuum there are common patterns of impact regardless of the drug(s) involved. 2. Predicting The Occurrence of Drug Dependencv Some people are more prone to develop abuse/addictive patterns of drug use than others. While we do not fully understand the c('mplex interaction, between environment, genetics and many olner factors it appears that some predictors are known. For example, a family history of drug abuse or addiction is associated with a higher probability of drug abuse/addiction. The extent to which this is related to genetics or learned environmental factors is not clear.

3 In the author's opinion, those individuals who are at the "extremes" of how they cope with life, or function generally, are more prone to utilize drugs to help them cope. Their own approach of being too controlled or the other extreme of poor impulse control brings them much emotional and physical stress and discomfort. These symptoms of discomfort are quickly and effectively relieved by many drugs. Those individuals are consequently receptive to such relief, and addiction often ensues Common Elements of Drug Dependencv There are certain common elements characteristic of addictive behaviour which exists whether we are dealing with a drugs, gambling, overeating or workaholic. Addiction to drugs is known to be a chronic condition, that is, a person once addicted cannot return to a non-addictive state. Once an addiction develops, a person is prone to develop addiction to other things. An alocholic can stop drinking and become healthy, but will always be an alcoholic. She cannot go back to "social" drinking. Addiction is progressive in that the person's physical, psychological and emotional condition continues to deteriorate while the drug is being used. Stopping use of the drug will arrest the progression, but does not necessarily ensure a return to a healthy, well-adjusted state. If drug use continues, things will get worse. Finally drug addiction is life threatening. The seriousness of the threat will depend on the drug, on the person and on the circumstances under which the drug is used. 4. Drug Use and Coping Essentially any drug use is a type of coping mechanism. Drugs are usually a fast, effective and reliable solution to a particular problem or need. If this problem or need occurred only once or rarely and is of short duration, the only drug concerns we would have relate to safety and efficacy of the drug used. Once the problem is solved and does not recur there would be no further need or demand for the drug.

4 When there is a recurring need which is met by the use of a drug, we have the ingredients that can lead to abuse and addiction. If the drug is capable of changing the way one feels and is perceived by the user as meeting or solving a recurring need, it becomes very easy for the user to choose this drug solution over other non-drug solutions. The non-drug solution may be a better choice, but might require time, effort, change, challenge, courage and any number of other ingredients to reach the point where it can be utilized. Meanwhile the need persists and the drug solution is known to work quickly, reliably and may have pleasurable effects as it works. These features reinforce the person to use the drug solution each time the need or problem arises. The drug abuse progression is dependent on the rate and frequency of occurrence of the need and subsequent drug use. Eventually the user develops a feeling or belief that this drug solution is the only method capable of meeting this (and related) recurring needs. This is what is often referred to as psychological dependence. It motivates further drug use, which may be in the absence of tolerance and dependence. When using a drug with dependence liability to meet a recurring need, it is just a matter of time before the body's adaptive responses come into play and begin the process which can lead to drug dependence and addiction. Understanding this process and the role the drug plays in each individual case can be very helpful in assisting a person with a drug problem. 5. Adaptive Responses or Tolerance To Drugs In response to a high dose or repeated exposure to a drug the body begins to adapt to the presence and interference caused by the drugs. The adaptive responses which have the greatest impact on the effects of the drug occur at the site of action or in the liver. Those adaptive changes occurring at the site of action contribute the most to the development of tolerance to the drug's actions. As the adjustments occur at the "neura-chemical" level some effects of the drug are diminished. That is, any drug-induced disturbance in a body system is brought back into balance by this adaptive response, thereby allowing the body to tolerate a given dose of the drug while maintaining normal body function. Of course the user eventually realizes that more drug, more often will bring the drug effects back. Tolerance may develop to each drug effect at a different rate and to a different degree. Those body functions most able to adapt to a given effect display the most prominent and intense withdrawal symptoms. It is these very adaptive (tolerance) mechanisms which seem to underlie the physical dependence and related withdrawal symptoms which may develop following repeated drug use.

5 5 6. Acute Effects in the Earlv Stages of Drug Abuse In the early days of drug use before a well established pattern is set, and before tolerance and physical dependence develop the primary concerns relate to the acute or immediate effects of a given drug in each episode of drug use. Of particular concern are: The impairing effects that make the user accident prone Drug interactions (Rx/OTC/illicit) Drug toxicity Therefore, when speaking to young people or their parents about drug abuse they can relate better to immediate consequences such as fights, a car accident, drug overdose or unwanted pregnancy. These points make more sense to them than speaking about the risk of "addiction" in the future or vague criticisms about "not meeting their responsibilities. II Linking these real risks to drug use is an important step in overcoming denial which is an integral part of most drug dependence. 7. Understanding Withdrawal Symptoms Withdrawal symptoms (or abstinence syndrome) occur when the concentration of drug at its' sight of action declines significantly below the level the person had adapted to after an episode of heavy use (binge) or chronic exposure. It is very important to realize that the user does not need to reach a state of total abstinence in order for withdrawal symptoms to occur. Of course, if complete discontinuation occurs then the extent of withdrawal will increase in intensity ("cold turkey"). There are two pharmacological principles which underlie drug withdrawal. The first helps us understand and predict the nature of the withdrawal symptoms. The other relates to the time course and intensity of withdrawal. PRINCIPLE NO.1: Withdrawal symptoms will be the opposite to the pharmacological effects of the drug.

6 That is, the body's adaptive responses lead to tolerance to specific drug effects. It is these very body system or functions which rebound with an intensity related the extent of drug use and hence tolerance. For example, drugs with a central nervous system depressant action will display withdrawal symptoms of over stimulation of the very system depressed by the drug. The pharmacist need only have a general knowledge of the actions of a given class of drugs (e.g.benzodiazepines), to be able to describe in general terms the withdrawal from Benzodiazepines. This principle applies to most drugs to which the body develops tolerance by way of it's adaptive responses. 6 PRINCIPLE NO.2: The time of onset, duration and intensity of withdrawal symptoms are determined by the rate at which the drug leaves it's site of action. This is best determined by the plasma half-life (T 1/2) of each drug. Drugs with a short half-life have a short duration of action. As this short half -life drug is cleared away from it's site of action quickly, the adaptive mechanisms are uncovered and are free to express themselves rapidly in the form of changes in the respective pathway (system or parameter). Withdrawal symptoms have a rapid onset (hours) and high intensity and may need medical management. The reverse of this example is also true. The concentration of long half-life drugs at their site of action declines slowly. Consequently the affected systems or pathways have more time to adjust back to normal so the manifestation of withdrawal symptoms is less pronounced, and spread over a longer period of time. These withdrawal symptoms may be easily mistaken for prior symptoms which were the basis to use the drug in the first place. However, more drug is seldom the right solution. These two pharmacological principles have become the foundation of modern day drug withdrawal management protocols in drug dependency treatment centres throughout the world. 8. Recognizing Drug Abuse and Drug Dependencv There is no one clinical or diagnostic test to identify or confirm the presence of drug abuse or dependence. The most reliable indicator of the presence of tolerance and physical dependence is the development of withdrawal symptoms upon discontinuation or reduction of the drug dose. These symptoms are quickly suppressed by the administration of the drug.

7 However, the most common means of diagnosing drug abuse and dependence involves a full assessment of the whole person and what impact drug use is having on the important aspects of life. Knowing the impact of drug use on the following categories provide important insights: Family life and relationships Financial situation Employment Health Social Conflict with law Another important consideration is the history of drug use, including drug type, frequency, duration, number of doctors and pharmacies utilized, etc. Obtaining all the above information is usually very difficult due to the denial by the user that there are any problems, or if there are problems, they are not seen to be related to the drug use. The more pieces of this complex puzzle you uncover the more effective one can be in dealing with the matter Working Together Due to the multifaceted nature of drug abuse and dependence, a "single handed" effort by any "one" person or professional is seldom successful at bringing about abstinence and/or recovery. Working closely with other resources and the key people in the life of the user are usually necessary and more fruitful. There is a great challenge in working with drug dependent persons and this challenge requires a cooperative effort by community resources. Ultimately, the drug user must walk their own road to reocvery. The helpers can only be the "guide"

8 8 PART TWO CLASSIFICATION OF DRUGS OF ABUSE AND DEPENDENCE 1. Putting your know/edge in perspective As a pharmacist (or other health professional) you know more than most people how difficult it is to keep all the different drugs straight. You know of the continual development and marketing of new drugs. You understand that a trade name may not have any relationship to which pharmacological family a drug belongs. You can imagine how overwhelmed a lay person becomes when trying to make sense of all the drugs they hear about or use. 2. Popular perceptions of drugs The lay person is more concerned about whether a drug does the job it is supposed to do with the least amount of adverse effects and disturbance to normal function. However, when they run into trouble and need help or information they have been instructed to consult their pharmacist or physician. You have an established credibility as a source of drug information. This makes it easier for you to transfer your knowledge to the topic of drug abuse. When it comes to drugs of abuse the public usually have a difficult time grasping the nature of the effects of most illicit drugs. Furthermore, if they need information they are at a loss to know where to turn to learn what they need to know. While there are many drug dependency agencies and information resources available throughout the country, their number doesn't come close to the number of pharmacists or pharmacies in the country. Clinical experience and research have identified the drugs most commonly involved in drug abuse and dependence (see accompanying chart and summary). It is clear from this, that drugs from many therapeutic categories are involved, as well as illegal, restricted, prohibited drugs and commercial chemicals. There is a tendency for the lay person (and many professionals) to think only of illegal drugs when speaking about drug abuse or dependence. It is important that you as a pharmacist do not reinforce such narrow thinking. As you probably know from your professional experience many

9 prescription and over-the-counter drugs are abused and become involved in dependence. From the point of view of abuse and dependence it does not matter whether a drug is over-the-counter, prescription, restricted or illegal in status. What matters is that a given drug (or any related drug) has a pharmacological action which meets the needs of the user, can be abused and/or lead to dependence. 3. Knowing the patient's point of view Drugs can be classified in many ways, by chemical family, by legal status, by prescribing control status, by therapeutic indication, by pharmacological effects, and many more categories. The public think of drugs in terms of: a. the disease or therapeutic purpose for which they are given (for example, "pain killers", sleeping pills, or muscle relaxants). b. or, the general nature of their pharmacological actions, for example, uppers and downers (stimulants and d~pressants). 9 People do not always understand the finer distinctions between an overthe-counter opiate (e.g. codeine) a prescription opiate (e.g. Demerol) or an illegal opiate (e.g. heroin). What really matters is that the nature of the effects of all three of these drugs are essentially the same. Real difference relates mainly to potency, and pharmacokinetic considerations. Yet the public may be lead to believe these drugs differ greauy in the nature of their pharmacological actions because they differ greatly in their legal status. When the public hear of the police referring to cocaine, cannabis, heroin and phencyclidine all as "narcotics" under the law, they think they all have a "narcotic-like" action. This is a common misunderstanding and causes further confusion when they attempt to understand the individual drug effects. Add to this the fact that they are exposed to many points of view about the effects or risks of a given drug. It is not surprising they are uncomfortable in their knowledge of drugs in general and drugs of abuse in particular. A PROVEN METHOD OF CLASSIFICATION Over the years we have tried different approaches to the way we present the drugs of abuse. We concluded that a simple and concise presentation works best and always.

10 10 We recommend this approach when speaking to the public about drugs of abuse: 1. Since the public think of drugs in terms of the purpose and the nature of their effects we suggest grouping them in categories consistent with the public's way of thinking. That is, by their general pharmacological effects. 2. Utilize the broad categories first then divide them into sub-groups based on slightly different, but dominant characteristics of their effects on the whole person. For example, many drugs of abuse and dependence are central nervous system depressants, such as alcohol, barbiturates, opiates, benzodiazepines. However, each of these examples could be discussed in relation to their own dominant characteristics as a group. For example, benzodiazepines and opiates differ in many of their effects. Opiates have a powerful analgesic effect while benzodiazepines do rot. 3. We have found that the more you focus on differences between drugs, the more you will "lose" the audience in your discussion and subsequently in their attention and interest. You may even get lost in the details yourself and cause further confusion. When your audience feels lost and that you are "over their head" they tend to withdraw. They feel the gap between where they are, and where you are, is too large to cover in such a session. Don't be afraid to ask them how you are doing "at making the topic understandable" for them, as you proceed through the presentation. 4. It is appropriate to discuss related information dealing with: - availability/accessability - adverse and toxic effects of significance - common drug interactions - compare generally the relative potency of one drug to another. Usually this sort of information is given in response to ql estions from the audience. But keep it simple and general.

11 11 Similarities vs. Differences We therefore place greater emphasis on those pharmacological effects which are common and which reinforce the user to continue using the drug. There are three main aspects of the drug's action which contribute to meeting the user's needs and reinforcing repeated use. A. The drug could be capable of relieving symptoms of pain or discomfort (physical or emotional) bringing a sense of relief, and associated improvements in mood (e.g. benzodiazepines). B. Many drugs of abuse create their own characteristic "euphoria" or good feelings, which are sought after by the user and can lead to repeated use (e.g. alcohol, cocaine). C. Some drugs can help the user improve performance or accomplish goals they think would not be accomplished without the drug (e.g. anabolic steroids, stimulants). CLASSIFYING THE DRUGS The following five categories have proven to be simple and very effective means of classifying drugs of abuse which the public readily understand. This approach also communicates the basic effects which reveal why they are so abused: 1. Central Nervous Svstem Stimulants We describe this group of drugs as those capable of causing most body systems to speed up. We point out that while there are different subgroups the general nature of their end effects on individual systems (e.g. cardiovascular, sensory-motor alertness) and on the whole body are similar. We give examples of effects on individual body systems to help the audience visualize the effects. Sometimes we even act out the typical effects to add to the imagery. (refer to the chart to see the drugs included in this category). 2. Central Nervous Svstem Depressants We describe this group of drugs as those capable of causing most body systems to slow down. We describe the general nature of this "slowing down process" and how it expresses itself in end behaviour or changes in body systems. Also we make the point (as we do in each category) that drugs in the sub-groups may differ in potency, duration and in other ways but their essential effects are similar. This keeps the facts to a minimum and allows you to focus on the prime issues.

12 12 3. Hallucinogens There are only a few true hallucinogens commonly used in this country. LSD, Lysergic Acid Diethylamide, is the classic prototype to which all others are usually compared. It is also the most available and has been for some time. Psilocybin is the active agent found in "magic mushrooms" which grow seasonally in parts of Canada. Often spoken about, but seldom if ever found in Canada, is mescaline from the peyote cactus plant. These three have similar hallucinogenic capabilities but have greatly different potency. LSD is the most potent of all the drugs of abuse commonly used, requiring only micrograms to bring on a full blown 6-12 hour period trip, including visual and auditory hallucinations and being out of touch with reality. They work by combining sensory stimulation with distortion and blend the various perceptions with the users' emotions and memories. This creates an experience in which the user believes many of the things going on in their mind are real and they behave accordingly, sometimes to their peril. Other drugs can cause hallucinations. Some do this by way of a general disruption in body chemistry resulting in a delirium type state, with vital functions compromised in the process. This is unlike what is seen with LSD. This type of hallucinogenic state is more related to the toxic or overdose effects of a given drug, then true hallucinations. Cannabis products in high doses can cause sensory distortion in combination with a general depressant effect resulting in visual and auditory hallucinations. However, cannabis products are not generally thought of as hallucinogens. 4. Mixed Action Drugs This category is used to cover some diverse agents we divide generally into two sub-groups: A. Organic solvents or inhalants - such as gasoline, nail polish solvents, glue, industrial solvents used in paint and for cleaning, and many similar products. B. Phencyclidine (PCP), (angel dust) - The dominant pharmacological effects of both categories are of the general depressant nature on the central nervous system and the functions controlled by it. However, each category is capable of causing such sensory, mood and emotional distortion that the user commonly experiences a variety of hallucinations and bizarre anti-social behaviour. After

13 the drug effects wear off the user often cannot remember many of the events (drug-induced amnesia or blackout) Image and Performance Enhancing Drugs In these days of intense competition, and the emphasis our society places on success, image and physical appearance, it is not surprising some people will turn to drugs capable of helping them meet these demands. The drugs chosen can be divided into: drugs which help build the body (e.g. anabolic steroids) drugs to help reduce size (e.g. diuretics) or suppress appetite drugs capable of increasing performance and productivity (e.g. stimulants anabolic steroids, analgesics) Once again the issue of what role the drug plays in the life of,the user determines the choice of drug. However, the choice of drug(s) may determine the nature and extent of "drug-related problems". A brief and simple review of key pharmacological effects and concerns related to each drug group can be the basis of a single presentation. Please refer to the following chart summarizing the various categories of drugs of abuse and dependence located at the end of this appendix.

14 14 CLASSIFICA TION OF COMMON DRUGS OF ABUSE AND DEPENDENCE 1. Central Nervous System Stimulants Nicotine (e.g. of sources) Caffeine (e.g. of sources) OTC/non-prescription agents - e.g.decongestants like phenylpropanolamine, and ephedrine Prescription - appetite suppressants,(diethylpropion, phenmetrazine) Amphetamines and derivatives Cocaine HCL (water soluble) (taken intranasaly and intravenously, as well as smokable by free-base liquid or " crack chunks" in pipe or cigarette). 2. Central Nervous System Depressants Alcohol Sedatives and Hypnotics,(benzodiazepines like Valium), OTC/ non-prescription cough and cold remedies, Antihistamine ( e.g. diphenhydramine) Opiates (codeine, meperidine, oxycodone, heroin etc.) Cannabis (marijuana, hashish, hash oil) (tetrabydroqannabinol=thc) 3. Hallucinogens LSD (ly~ergic acid djethylamide="acid" Psilocybin (magic mushrooms) Mescaline (peyote plant) High dose of THC from cannabis Miscellaneous other agents in high doses (e.g. some antihistamines)

15 15 4. Mixed Action - Drugs which act through a mixture of stimulant, depressant and/or hallucinogenic actions. A: Poisons: Cleaning fluids: petroleum, distillates, naphtha Nail polish remover: acetone, toluene Gasoline: petroleum, distillantes, toluene Glues and plastic cements: toluene, Aerosol sprays: variety of toxic chemicals B: Illicit Drug: Phencyclidine-(PCP, "angel dust") (Originally an animal general anesthetic, depressant with hallucinogenic effects) 5. Image and Performance Enhancing Drugs Anabolic steroids to build size and strength. Appetite suppressants to control body size and shape. Stimulants, local anesthetics, pain relievers and corticosteroids, to aid performance.

16 ftharmamou' TEL. (902) "" ft Consultants in Pharmacology and Toxicology FAX. (902) INCORPORATED Professional Services ill: Education, Forensic, Environmental, Workplace, Addiction and SAFE DRIVER Program UNIT 7,101 ILSLEY AVENUE DARTMOUTH, NOVA SCOTIA B3B 1S1 P.O. BOX 3506, D.E.P.S. DARTMOUTH, N.S. CANADA B2W 5G, The following is a brief profile of Gregory 1. Johnstone, M.Sc., President of Ph armato x Inc. GREGORY J. JOHNSTONE, M.Sc. (PharmacologylToxicology) - Mr. Johnstone holds a Master of Science from Dalhousie University specializing in Pharmacology and Toxicology. Mr. Johnstone has developed a unique set of skills which allows him to present the complicated interplay between drug effects, chemicals, people and the environment in an accurate and understandable way. In his private practice as a consultant, he has been designated by the courts as an expert witness in the areas of Pharmacology and Toxicology. He is recognized as such throughout Canada. Mr. Johnstone provides a wide range of services to the legal profession and the courts in relation to the role alcohol, drugs and chemicals play in criminal and civil matters. Mr. Johnstone has developed a number of innovative education programs. The Safe Driver Program is an example of an education program directed at behavioral change in a high-risk, resistant population. He has also developed and delivered the Community Education Guide for Pharmacists across Canada. His teaching experience covers a broad range of students from medical school, health professionals, university and public schools throughout Canada. His experience coupled with his dynamic speaking skills helps audiences grasp complex ideas quickly and accurately. Mr. Johnstone spent 14 years as supervisor of Pharmacology Programs with the Nova Scotia Commission of Drug Dependency. In that capacity he was responsible for the development of treatment standards and played an important role in the clinical management of patients involved in a wide variety of drugs of abuse.