According to the Oxford Dictionary of Nursing, a drug is defined as any substance that affects the structure or functioning of a living organism. It is a very powerful and useful substance that people use to prevent, diagnose and treat their diseases, without these drugs sick people could not heal or recover quickly and their symptoms could not be relieved. The study of drugs is known as Pharmacology. This term comes from two Greek words "pharmakon" meaning drug and "logia" meaning study. Pharmacology covers all aspects of drug knowledge. (Adams, Holland & Urban, page 3) The discussions of this essay are as follows: First, the sources of drugs, what they are called, and examples of drugs derived from those sources will be discussed. Secondly, I will move on to discuss drug absorption and the five factors that influence it. Third, I will elaborate on how the drugs are administered. Fourth, I will discuss the adverse effects of the drug and drug interaction and finally I will move on to discuss the drug that I have chosen and an example of the drug that we will talk about is morphine. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay Drugs are derived from natural and synthetic sources. A natural product is defined as a chemical compound or substance produced by a living organism, i.e. present in nature, such as plants, animals, microorganisms and minerals. An example of drugs derived from the plant is Digoxin. Digoxin is a drug that comes from the leaves of the plant called Digitalis purpurea. Insulin is an example of a drug that comes from the pancreas of a pig/cow, for animals. Regarding the source of microorganisms, penicillin is an example of a drug that comes from the microorganism called penicilium notatum. The last source is known as mineral source and an example of a drug that comes from this source is known as ferrous sulfate which is used to treat anemia and other drugs include iron, iodine and potassium salts. Moving forward, synthetic drugs are the opposite of natural drugs because they are created using man-made chemicals. Some of the examples include semi-synthetic and biosynthetic drugs. Semi-synthetic drugs are prepared by chemical modification of natural drugs, an example is ammpillicin from penicillin G. On the other hand biosynthetic drugs are prepared by cloning human DNA into bacteria like E. coli and an example of this drug is human insulin. Researchers have shown that one of the advantages of this chemically developed drug is that they are free from impurities present in natural substances. (Kluwer. W, 2013) Furthermore, drugs are named using a nomenclature whereby one drug can have three different names. These names include the chemical name, generic also known as non-proprietary and trade or proprietary name. The chemical name describes the anatomical and molecular structure of the drug. The generic name is an abbreviation of the chemical name, and the trade name is selected by the pharmaceutical company that sells the product. Furthermore, “Absorption is the movement of drug particles from the gastrointestinal tract into body fluids by passive absorption, active absorption, or pinocytosis.” (Kee, Hayes & Mc cuistion, 2015) It is a process that occurs from the moment a drug enters the body to the moment it enters the bloodstream to be put into circulation. Diffusion is an example of passive absorption and occurs when drugs move across the membrane without requiring energy. Energy is needed forActive uptake and pinocytosis is a process by which cells transport a drug across their membrane by engulfing drug particles. In addition to this it is important to note that fat-soluble, non-ionized drugs are absorbed faster than water-soluble, ionized drugs. There are some factors that influence the absorption of the drug and this includes: Dosage form Route of administration Blood flow at the site of administration Gastrointestinal function Presence of food or other drugs Pain, stress, hunger and fasting Furthermore, understanding the principles of pharmacology is very important in the administration of the drugs drugs because if the drugs are administered incorrectly the patient's health condition can worsen and ultimately lead to death. Right off the bat, there are eleven ways to administer the drug. The first is known as buccal, sublingual and translingual. For the mouth medications such as nitroglycerin are administered into the sac between the cheek and teeth, under the tongue for sublingual and translingual medications are administered on the tongue. The gastric route is the second route and allows the direct administration of a drug into the gastrointestinal system. The third administration is known as intradermal and involves injecting drugs into the skin. The fifth is Intramuscular; this route allows drugs to be injected directly into the various muscle groups. The sixth is the intravenous route which allows the injection of drugs and other substances directly into the bloodstream through a vein. The seventh is oral administration in which drugs are administered orally to patients who are conscious and able to swallow. The eighth is the rectal and vaginal one, which is why some drugs are applied to the mucosa of the rectum or vagina and can also be absorbed systemically. The ninth administration is known as subcutaneous administration where small amounts of drugs are injected under the dermis and into the subcutaneous tissue. The topical route is the tenth route and is used to administer a drug through the skin or mucosa. The last type of drug delivery is known as specialized infusions. These are administered directly to a specific site in the patient's body as epidural (injected into the epidural space) and intrapleural (injected into the pleural cavity). (Raju, S. M & Chandra. S, 2009) Adverse drug effect, also known as adverse drug reaction, is defined as "any unwanted or unwanted effect following the administration of a medical product, regardless of whether the effect is considered related or not to the medical product” ( Woo & Robinson, 2016, page 51) It is important to note that understanding the causes and mechanisms of adverse drug reactions and developing practices to predict and prevent their occurrence can help reduce morbidity (quality of being ill) and mortality. There are two basic types of adverse drug reactions: known as pharmacological and idiosyncratic (Aronson & Ferner, 2003). mechanism of action of the drug. On the other hand, idiosyncratic reactions often lead to mortality because they are unpredictable or changeable. Since the drug reaction is dose-dependent and includes: side effects, hypersensitivity, overdose and iatrogenic effects. Side effects are produced by a drug in a positive or negative way. Morphine, for example, can be used to control pain and can lead to two unpleasant side effects which are constipation and respiratory depression. Secondly, hypersensitivity is the result of higher than expected blood concentration levels due to altered pharmacokinetics(absorption, metabolism and excretion). Third, when an excessive dose (overdose) is taken, a toxic reaction to the drug may occur. This can lead to more serious reactions such as respiratory depression, cardiovascular collapse, and even death. Finally, latrogenic effects can mimic or imitate pathological disorders. Drugs such as antineoplastics, aspirin, corticosteroids, and indomethacin, for example, commonly cause gastrointestinal irritation and bleeding. (Wolters, 2013) Drug interactions occur when a substance affects the activity of a drug when both are administered together. It can occur between drugs or between drugs and foods. They may interfere with the results of a laboratory test or produce physical or chemical incompatibilities. It is important to know that the more medications a patient receives, the more likely a drug interaction is to occur. Anti-obesity drugs will be discussed as an example. An obesity drug is a type of medication that obese patients (with health problems) take to improve their health condition by losing weight. These medications include appetite suppressants and fat blockers (orlistat). Anti-obesity drugs have the following interactions: Appetite suppressants taken with cardiovascular stimulants can increase the risk of hypertension and arrhythmias, when taken with central nervous system stimulants, appetite suppressants can cause anxiety and insomnia. On the other hand, taking orlistat with fat-soluble vitamins blocks the absorption of the vitamins. Furthermore, the name of the drug that I have identified and will discuss in this essay is known as morphine. Morphine is a very powerful drug that people use to relieve pain. This medication belongs to a class of drugs known as oploid analgesics (narcotics). To delve deeper into the history of this drug, it can be said that Friedrich Serturner was a German pharmacist and is best known for his discovery of morphine in 1804. He isolated this active ingredient from a plant between 1803 and 1805. Morphine is found occurs naturally in a number of plants and its primary source is isolation from the straw of the opium poppy. It can be found under generic and brand-name products including Oramorph SR, Roxanol, and Kadian. Morphine is available in several forms and these include oral solutions, immediate- and prolonged-release tablets and capsules, injectable preparations and suppositories. Oral solutions are the first form and this form comes in the form of a liquid. This form is commonly given to patients who have difficulty swallowing pills. Secondly, it is important to note that breaking, crushing or chewing morphine tablets and capsules is not allowed as much of it will be released into the bloodstream and could contribute to various problems. Third, morphine injections are commonly used for surgical preparations and finally morphine suppositories are used when a patient needs a longer-lasting dose but has difficulty swallowing and only needs to be inserted into the rectum. In addition to this, morphine is administered orally (by mouth), by injection into the muscle and by injecting it under the skin. The dosages of this drug are as follows: First, the starting dose of the immediate-release tablet is between 15 and 30 mg. Secondly, for subcutaneous therapy the initial dose administered is 10 mg every hour for 4 hours as needed. Finally, the IV dosage varies from 5 to 15 mg and the initial dose is 4 to 10 mg administered slowly over 4 to 5 minutes. One of the ways that morphine affects the body is that it acts directly on the central nervous system to decrease the sensation of pain..