What are medicinal drugs? Explain the sources of medicinal drugs.
The chemical substances that are used in the diagnosis, cure, treatment or prevention of a disease are called medicinal drugs.
Various diseases have been made easier to treat in recent years by the production of medicinal drugs.
SOURCES OF DRUGS
Drugs are obtained from the following sources:
1. Synthetic drugs
2. Drugs from plants
3. Drugs from fungi
4. Drugs from animals
5. Drugs from minerals
6. Drugs from bacteria
1. Synthetic drugs:
Such drugs do not occur naturally but are synthesized in laboratory. Pharmaceutical companies produce these drugs.
2. Drugs from Plants:
Many important drugs are obtained from plants. These medicines include:
• Certain analgesics Examples:
It is a cardiotonic which is used to stimulate the heart.
It is made from the leaves of purple flowered plant, foxglove.
It is a pain reliever. Source:
It is obtained from opium, which comes from the juice of poppy plant.
Many addictive illegal drugs are also obtained from plants e. g.
3. Drugs from Fungi:
Some medicines are obtained from fungi.
The antibiotic penicillin is obtained from a fungus, Penicillium notatum.
4. Drugs from Animals:
Drugs obtained from animals are usually their glandular products.
Examples: The following are obtained from animal sources:
• Fish liver oil
• Bee's wax
• Certain hormones
5. Drugs from Minerals:
Several common drugs are produced from minerals:
The mineral iodine is used in making tincture of iodine.
It is a liquid that helps prevent infection when applied to cuts and bruises.
The powder form of silver nitrate is applied on wounds to stop bleeding and prevent infections.
6. Drugs from Bacteria:
Many antibiotics are obtained from bacteria:
Describe the principal usage of important medicinal drugs.
PRINCIPAL USAGE OF IMPORTANT MEDICINAL DRUGS
The drugs are classified on the basis of
• Chemical properties
• Modes of action
The principal usage of important medicinal drugs is as follow:
These are the pain killers. These reduce pain.
These inhibit or kill bacteria with in or on the body and treat bacterial infections. Examples:
These induce sedation by reducing irritability or excitement.
These are used to develop immunity against viral and bacterial infections.
• Whooping cough
• Hepatitis B
These reduce the possibility of infections on skin.
• Tincttire of iodine
These destroy microorganisms found on non-living objects.
What precautions should be taken before taking medicines?
PRECAUTIONS FOR THE USAGE OF MEDICINES
Medicines can help you feel better. But if medicines are taken incorrectly, they can actually make you feel worse. The following precautions should be kept in mind:
2. Expiry Date
3. Self Medication
5. Treatment Discontinuation
6. Dosage for Children
9. Children's Reach
10. Tampered Medicines
Always check the instructions on doctor's prescription slip and make sure you take the doses of medicine strictly as your doctor prescribed.
2. Expiry Date:
Always check the expiry date printed on the medicine pack. The expired medicines may prove poisonous.
3. Self Medication: •
Never take medicines prescribed for someone else, even if you think you have the same medical problem.
Some medicines - such as antibiotics - must be taken for a specific number of days. Make sure you take the medicine for the fated time. Otherwise the problem may come back again.
5. Treatment Discontinuation:
Always check with your doctor before you top t king a medicine or consider a new treatment.
6. Dosage for Children:
Some medicines are not suitable for children, and there are special children's dosages for many medicines.
7. Darkness: Do not take medicine in the dark.
8. Carriage: If your prescription medicines are crucial for your heath and life, carry medicines and dosage instructions with you, when ever you are out of home.
9. Children's Reach:
Always keep healthcare products out of the reach of children.
10. Tampered Medicines:
Do not use the medicine if there are signs of tampering. Inform the pharmacist and the manufacture of the medicine, about it.
Write a note on addictive drugs.
The drugs that make person dependent on them or addicted are called addictive drugs.
By using addictive drug, the person's body becomes familiar to it and the user can not function well with out it.
CATEGORIES OF ADDICTIVE D_RUGS
The following are major categories of addictive drugs:
These drugs induce sedation by reducing irritability or excitement.
Mode of Action:
These drugs interact with central nervous system to depress its activities.
Effects: Sedative drugs induce:
• Slow brain function
• Depression Long Term Use: Long term use of sedative drugs induces suicidal thoughts.
Narcotics are strong pain killers.
These drugs are often prescribed in conjunction with other less potent pain killers like paracetamol or aspirin.
These are used to relieve pain for patients with chronic diseases like cancer. These are also used to relieve acute pain after operations.
But some people may abuse narcotics for ecstatic effects.
Morphine is derived from opium (poppy). It acts directly on central nervous system to relieve pain. Morphine has a high potential for addiction.
It is also derived from opium.
It is the most commonly abused narcotic. It is semi-synthetic drug from morphine. It effects on central nervous system and causes drowsiness.
Usage in Western Countries:
In many western countries, heroin is prescribed as a strong analgesic under the name diamorphine. Its use includes treatment for acute pain, such as:
• Severe physical trauma
• Myocardial infarction
• Post-surgical pain
Hallucinogens are the drugs•that cause changes in:
Mode of Action:
Physiologically, hallucinogens affect on the sympathetic nervous system causing:
• Dilation of pupils
• Constriction of some arteries
• Rise in blood pressure Examples:
Mescaline is derived from cactus.
Psilocin is derived from a mushroom.
Marijuana is a hallucinogen, which is smoked.
It is obtained from the flowers, stems and leaves of the marijuana plant.
• Cannabis sativa
• Cannabis indica Less Dosage:
Small doses of marijuana result in a feeling of well being that lasts for two to three hours. High Dosage:
High doses increase heart rate.
It also effects the production of sperms in men and also weakens the short-term memory. Usage:
Marijuana is one of the most commonly used drugs in the world, followed by caffeine, nicotine and alcoholic beverages in popularity.
Explain problems with drug addiction.
PROBLEMS WITH DRUG ADDICTION
There is a lung list of drug related associated problems, some of them are as follow: Withdrawal of Social Contact:
Drug abusers go through withdrawal of social contact or communication. The addicts are very weak in their social behaviour. They face social stigma i.e. the society dislikes them because of their unpredictable behaviours.
Problems for Government:
The jails and prisons of our country are full of such people who have committed no other crime than the illegal possession of narcotics.
Increase in Crime Rate:
Many studies by the experts of social sciences prove that there exists a close relationship between drug addiction and crime. The compulsion for narcotic drug makes every drug addict a criminal.
The drug addicts are law violators. Mere possession of a narcotic drug is violation of the law. Thus, every drug addict is subject to arrest by the police.
Drug addicts may commit violent crimes since so many become psychic patients. Other Crimes:
Most narcotic addicts get involved in various types of crimes, like:
• Shop lifting
What are antibiotic? Explain major groups of antibiotics.
An antibiotic is a drug that kills or retards the growth (reproduction) of bacteria. They are the chemicals produced by or derived from microorganisms like bacteria and fungi.
Types of antibiotics:
There are two main types of antibiotics:
The antibiotics that kill the bacteria are called bactericidal antibiotics.
The antibiotics that work by stopping the bacterial growth are called bacteriostatic antibiotics.
GROUPS OF ANTIBIOTICS
There are three major group of antibiotics:
3. Sulpha Drugs — Sulfonamides
Mode of action:
Cephalosporins interfere with the synthesis of bacterial cell wall.
These are bactericidal antibiotics.
Cephalosporins are used to treat
• Sore throat
Mode of Action:
Tetracyclines inhibit bacterial protein synthesis.
These are broad-spectrum bacteriostatic antibiotics.
Tetracyclines are used in the treatment of infections of:
• Respiratory tract
• Urinary tract
Tetracyclines are not used in children under the age of 8, and especially during periods of tooth development.
3. Sulpha Drugs — Sulfonamides:
Sulpha drugs are synthetic antibiotics that contain sulfonamide group.
Sulfonamides are broad spectrum bacteriostatic antibiotics.
Mode of Action:
They inhibit the folic acid synthesis of bacteria.
They are used to treat:
• Urinary tract infections
Write a note on antibiotic resistance.
Antibiotics are extremely important in medicine, but unfortunately bacteria are capable of developing resistance to them. Such bacteria are not affected by commonly used antibiotics. Definition:
The ability of bacteria not to be affected by the particular antibiotic is called antibiotic resistance.
When bacteria are exposed to the same antibiotic over and over, they can change and are no longer affected by the drug.
WAYS OF DEVELOPING RESISTANCE
Bacteria have number of ways of developing resistance.
Stoppage by Internal Mechanism:
Sometimes, their internal mechanism stops the working of antibiotic.
Transfer of Genes:
Bacteria can also transfer the genes responsible for antibiotic resistance between them. So such resistance bacteria make it possible for other bacteria to acquire resistance.
Another reason for increasing antibiotic resistance in bacteria is their use in diseases in which they have no efficacy e.g. antibiotics are not effective against infections caused by viruses. A Growing Problem:
Resistance to antibiotics poses a serious and growing problem, because some infectious diseases are becoming more difficult to treat. Some of the resistant bacteria can be treated with more powerful antibiotics, but there are some infections that do not eliminate even with new antibiotics:
Write a note on vaccines. Explain mode of action of vaccines.
A material containing weakened or killed pathogens and is used to produce immunity to a disease by stimulating the production of antibodies is called a vaccine.
Work of Edward Jenner:
In 1796, a British physician, Edward Jenner, infected a young boy with cowpox. by injecting pus cells. After the boy had recovered from cowpox, Jenner injected the pus cells from a smallpox patient into him. The boy did not get smallpox.
So it became clear that intentional infection with cowpox protected people from smallpox.
This method was named "vaccination" and the substance used to vaccinate was called a "vaccine".
MODE OF ACTION OF VACCINES
Pathogens contain special proteins called "antigens".
When pathogens enter the body (blood) of host, these proteins stimulate the immune response in host i.e. synthesis of "antibodies". Antibodies bind to pathogens and destroy them. Production of Memory Cells:
In addition, "memory cells" are produced, which remain in blood and provide protection against future infections with the same pathogen.
Stimulation of White Blood Cells:
When a vaccine i.e. weakened or dead pathogen is introduced into bloodstream, the white blood cells are' stimulated.
Recognition by B-lymphocytes:
B-lymphocytes recognize the weakened or dead pathogens as enemies and start producing antibodies against them.
Protection against Pathogens:
These antibodies remain in blood and provide protection against pathogens. If real pathogenenter Wood. the already present antibodies kill the