SCHOOL BIOLOGY: DRUGS
Class Handout for BGCSE No 1
| A drug is any substance taken from an external source which alters or affects the body chemical reactions |
METHODS OF DRUG ADMINISTRATION
- Oral – drugs taken through the mouth e.g. tablets & syrup.
- Injection
- Intravenous; directly into the veins.
- Intramuscular; into the muscles.
- Inhalation
- Sniffing, e.g. tobacco snuff.
- smoking e.g. cigarettes
- Other methods include implants (attachments to the skin) and placing the drug into other natural openings such as vagina, anus, ears and eyes.
TYPES OF DRUGS
Medicinal Drugs
These drugs are used to aid the body in fighting infections or diseases OR to help it work in a specific way.
Examples of medicinal drugs
- Painkillers/Analgesics: Act on the part of the brain which interprets pain. Mild painkillers include Aspirin and Paracetemol / Panado. Powerful painkillers include heroin and morphine which come from the opium poppy flower. The body becomes addicted to the powerful painkillers very quickly.
- Antibiotics: they are used to treat bacterial diseases e.g. Amoxicillin and Penicillin.
- ARVs: These are used to suppress the effectiveness of retro-viruses such as HIV.
- Vaccines: they help the body to develop the immune system.
- Contraceptives: they are used for birth control and family planning.
- Antacids: they neutralize excessive gastric acid to prevent heartburn and indigestion.
- Anesthesia: They are used to suppress any feeling of pain and induce numbness during surgical procedures e.g. in tooth extraction.
- Tranquilizers/sedatives: they slow down the nervous system. These drugs are used in cases of mental disorders such as persistent insomnia or schizophrenia.
- Drugs may cause unwanted side-effects e.g. headaches, rashes or more serious allergic reactions.
| Why do you think antibiotics and ARVs must be used according to the Doctor's prescription? |
Examples of non medicinal drugs
These drugs are used for recreation because of their mood enhancing properties e.g. alcohol, cocaine, marijuana, etc. Some drugs which are meant for medicinal purposes may also be abused and fall into this category e.g. morphine.
- Stimulants – Speed up the action of the brain and make you alert.
eg. Caffeine a mild stimulant is found in coffee, tea and Coca Cola. Nicotine is a stimulant found in tobacco. Cigarette smokers are at further risk from cigarette associated disease e.g. lung cancer, bronchitis etc. Cocaine is a powerful stimulant made from the leaves of a plant in South America. It is highly addictive. Misuse of strong stimulants causes severe brain damage.
- Depressants – Slow down reactions, e.g. alcohol.
Reaction time is greatly increased which can lead to harm to both the user and others around. A large number of road traffic accidents in Botswana result from alcohol abuse. There are many other health and social problems associated with addiction and alcohol abuse. These include theft and other criminal activities, family break ups, family violence, mismanagement of personal resources such as finance, tensions, poverty, HIV infection and abuse/rape, and ill health such as liver cirrhosis, malnutrition and mental disorders.
- Hallucinogens - Causes the person to see and feel things that are not real. They affect the nervous system. These include drugs such as cannabis (a.k.a dagga/marijuana/ganja/grass/etc) and LSD (a very dangerous man-made chemical) causes mental and emotional problems (depression).
DANGERS OF DRUG MISUSE
- Drug Dependece - the body becomes used to the drug and cannot function properly without it.
- DAMAGES BODY CELLS - Continued drug use damages cells, tissues and organs. Immunity is reduced and a drug user is more prone to infection.
- Heart disease is more common as excess strain is put on the heart.
- HIV / AIDS is more common in intravenous drug users (injecting the drug with a needle) since needle sharing is common.
- ACCIDENTS and INJURY incidents are increased since the drugged person is clumsy and has slow reaction.
- SOCIAL IMPLICATIONS - money is needed to pay for drugs. This often leads to theft and other criminal activities, family, tensions, poverty and abuse/rape.
Drug Tolerance
When a drug has been taken over a long period of time, the user has to gradually increase the dosage in order to produce the original response/feeling. E.g. a person starting to drink alcohol may require 3 or 4 beers to get drunk. After drinking for several years, the same person may require 8 or 9 beers to get drunk. This means his/ her body tolerates the drug. Excessive consumption of the drug may lead to poisoning of tissues which may eventually result in death.
Drug Dependence
This means a condition whereby a person is unable to live without using the drug/substance. There are two types of dependence
Emotional (psychological) dependence
The user is driven for psychological reasons to use the substance to help him/her to think, work or cope in everyday life. They develop cravings for the drug and may become bad tempered, anxious or depressed without it.
Physical dependence
The body metabolism ahs been altered to accommodate the substance. It involves similar experiences as in emotional dependence. However it also involves physical effects known as withdrawal symptoms if the person is unable obtain the drug. These include nausea, headache, muscular pain, hallucination, vomiting, diarrhea, and uncontrollable shaking. Physical dependence is commonly known as addiction.
ALLERGIC REACTIONS
An allergy is an over reaction of the body immune system (which may be harmful to the body) to a substance that is usually harmless. A substance that triggers an allergic response is known as an allergen. Examples of common allergens are milk, bee venom, pet dander, pollen, moulds, mites, house dust and drugs. Symptoms of allergic reaction include rash, itching, swelling, wheezing (in asthma), sneezing, diarrhea, muscle cramps, watery eyes, and blocked nose.
An allergy is an over reaction of the body immune system (which may be harmful to the body) to a substance that is usually harmless. A substance that triggers an allergic response is known as an allergen. Examples of common allergens are milk, bee venom, pet dander, pollen, moulds, mites, house dust and drugs. Symptoms of allergic reaction include rash, itching, swelling, wheezing (in asthma), sneezing, diarrhea, muscle cramps, watery eyes, and blocked nose.
When an allergic person gets into contact with an allergen, the body produces substances called histamines. These dilate capillaries in the local area and cause fluids to leak into the surrounding tissues. This is in turn causes inflammation (swelling & redness) that result in constricted airways, mucus secretion, lack of intestinal absorption, and other malfunctions.
Allergies may be prevented/treated by
- avoiding contact with the allergen
- use of drugs called anti-histamines
- Desensitization shots (giving small doses of the allergen to get the body used to it, then gradually increasing the dose).
| *Drugs are administred into the body thru several methods *They maybe used for medicinal or non-medicinal purposes *misuse of drugs may lead to health and social problems *Some drugs trigger allergic response |
