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The Sources of Drugs, Drug Absorption and How Drugs Are Administered

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According to 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 in order to prevent, diagnosed and treat their diseases, without these drugs people who are sick would not be able to be healed or recover quickly and their symptoms would not be able to be relieved. The study of drugs is known as Pharmacology. This term is derived from two Greek word ‘pharmakon’ meaning a drug and ‘logia’ which means study. Pharmacology covers all aspects of knowledge of drugs. (Adams, Holland & Urban, Page 3) The discussions of this essay are as follows: Firstly, it will discuss the sources of drugs, how they are named and examples of medications derived from those sources. Secondly, I will move on to discuss drug absorption and the five factors that affect it. Thirdly, I will elaborate how drugs are administered. Fourthly, I will discuss the adverse effect of drug and drug interaction and lastly I will move on to discuss the drug that I have chosen and an example of the drug that will be discussed is Morphine.

Drugs are derived from natural and synthetic sources. Natural product is defined as a chemical compound or substance produced by a living organism-that is, found in nature, such as plants, animal, microorganism and mineral. An example of medications derived from plant is Digoxin. Digoxin is a drug that comes from the leaves of the plant named Digitalis purpurea. Insulin is an example of a drug that comes from the pancreas of a pork/cow, for animals. For microorganism source, Penicillin is an example of medication that comes from the microorganism named penicilium notatum. Last source is known as the mineral source and an example of a drug that comes from this source is known as ferrous sulphate which is used for treating anaemia and other drugs include iron, iodine and potassium salts. Moving on, synthetic drugs are the opposite of natural drugs because it is created using man-made chemicals. Some of the examples include semisynthetic and biosynthetic drugs. Semisynthetic drugs is prepared by chemical modification of natural drugs, an example is ampillicin from penicillin G. On the other hand biosynthetic drugs are prepared by cloning of human DNA into the bacteria like E. coli and an example of this drug is the human insulin. Researchers had shown that one of the advantages of this chemically developed drug is that they are free from the impurities found in natural substances. (Kluwer. W, 2013) In addition to this, drugs are named using nomenclature whereby a drug can go by three different names. These names include the chemical, generic also known as non-proprietary and trade or proprietary name. The chemical name describes the drugs anatomic and molecular structure. The generic name is an abbreviation of the chemical name and the trade name is selected by the drug company selling the product.

Moreover, “Absorption is the movement of drug particles from the gastrointestinal tract to body fluids by passive absorption, active absorption or pinocytosis”. (Kee, Hayes & Mc cuistion, 2015) It is a process that occurs from the time a drug enters the body to the time it enters the bloodstream to be circulated. Diffusion is an example of passive absorption and it occurs when drugs move across the membrane without requiring any energy. Energy is required for active absorption and pinocytosis is a process by which cells carry a drug across their membrane by engulfing the drug particles. In addition to this it is important to note that lipid soluble and non-ionized drugs absorbed faster than water soluble and ionised drugs. There are some factors that affect drug absorption and this include:

  • Dosage form
  • Route of administration
  • Blood flow to the site of administration
  • Gastrointestinal function
  • Presence of food or other drugs
  • Pain, stress, hunger and fasting

Additionally, understanding the principles of pharmacology is very important in drug administration because if medications are given incorrectly then the patient health condition can deteriorate and eventually lead to death. Instantly, there are eleven ways of administering the drug. The first one is known as the buccal, sublingual and translingual. For buccal the drug such as nitro-glycerine are given in the pouch between the cheek and teeth, under the tongue for sublingual and translingual drugs are given on the tongue. Gastric route is the second route and it allows direct administration of a drug into the gastrointestinal system. The third administration is known as Intradermal whereby drugs are injected into the skin. The fifth one is Intramuscular; this route allows drugs to be injected directly into various muscle groups. The sixth one is intravenous route which allows injection of drugs and other substances directly into the bloodstream through a vein. The seventh one is oral administration where drugs are given orally to patients who are conscious and able to swallow. The eighth one is rectal and vaginal, for this some drugs are applied to the mucosa of the rectum or vagina and can also be absorbed systemically. The ninth administration is known as the subcutaneous administration whereby small amounts of drugs are injected beneath the dermis and into the subcutaneous tissue. Topical route is the tenth route and this route is used to deliver a drug via the skin or a mucous membrane. The last type of drug administration is known as the specialized infusions. These are given directly to a specific site in the patient’s body such as epidural (injected into the epidural space) and intrapleural (injected into the pleural cavity). (Raju, S. M & Chandra. S, 2009)

Adverse effect of drugs also known as the adverse drug reactions is defined as, “ any undesirable or unintended effect following administration of a medical product, whether or not the effect is considered related 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 to reduce morbidity ( quality of being sick) and mortality. There are two basic types of adverse drug reactions: known as the pharmacological and idiosyncratic (Aronson & Ferner, 2003). A pharmacological reaction is typically dose related and is able to be predicted based on the drugs mechanism of action. On the other hand, idiosyncratic reactions often result in mortality because they are unpredictable or changeable. Since pharmacological reaction is dose related and it includes: secondary effects, hyper susceptibility, overdose and iatrogenic effects. Secondary effects are produced by a drug beneficially or adversely. Morphine for example can be used for pain control and can lead to two unpleasant secondary effects which are constipation and respiratory depression. Secondly, hyper susceptibility is a result of having higher than expected blood concentration levels due to alteration of pharmacokinetics (absorption, metabolism and excretion). Thirdly, a toxic drug reaction can occur when an excessive dose is taken (overdose). This can lead to more serious reactions such as, respiratory depression, cardiovascular collapse and even death. Lastly latrogenic effects can mimic or imitate pathologic disorders. Drugs such as antineoplastic, 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 can interfere with the results of a laboratory test or produce physical or chemical incompatibilities. It is important to know that the more drugs a patient receive the greater the chances are that a drug interaction will occur. Obesity Drugs will be discussed as an example. An obesity drug is a type of drugs that obesity patients (with health problems) take in order to improve their health condition with weight loss. These drugs include appetite suppressants and fat blockers (orlistat). Obesity drugs have the following interactions: Appetite suppressants taken with cardiovascular stimulants may increase the risk of hypertension and arrhythmias, when taken with CNS stimulants, appetite suppressants can result in anxiety and insomnia. On the other hand, taking orlistat with fat soluble vitamins blocks vitamin absorption.

Furthermore, the name of the drug that I have identified and will be discussing in this essay is known as morphine. Morphine is a very powerful drug that people use in order to relieve their pain. This drug belongs to a class of drugs known as oploid (narcotic) analgesics. To elaborate on 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 naturally in a number of plants and its primary source is isolation from poppy straw of the opium poppy. It can be found under generic and brand name products including Oramorph SR, Roxanol and kadian. Morphine comes in different form and these include oral solutions, immediate and sustained 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 a hard time in swallowing their pills. Secondly, it is important to note that morphine tablets and capsules that breaking, crushing or chewing these morphine tablets and capsules is not allowed since a lot of it would be released into the bloodstream and can contribute to various problems. Thirdly, morphine injections are commonly used for surgery preparations and lastly morphine suppositories are used when a patient needs a longer lasting dose but having difficulty in swallowing and it should only be inserted into the rectum. In addition to this, morphine is administered through orally (given by mouth), by injection into the muscle and injecting it under the skin. The dosages of this drug are as follows: firstly, the initial dose immediate release tablet is 15 to 30 mg. Secondly, for subcutaneous the initial dose that is given is 10mg every hour 4 hours as needed. Lastly the dosage for IV ranges 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 in which morphine affects the body is that it acts directly to the central nervous system to decrease the feeling of pain. It decreases the transmission of pain impulses in the body by interrupting the pain messages in the spinal cord and interfering with the messages coming from the brain in the central nervous system. In addition to this the nursing advise that I will give to the patients who are being discharged taking morphine as their drugs are as follows: firstly, I will tell the patient to keep the drug tightly closed in the container it came in and out of reach of children. Secondly, I will tell the patient not to throw the drug outside the house, keep it away from pest to avoid poisoning since the drug is highly toxic in nature. Lastly I will tell the patient to inform the doctor if any side effect is shown.

At the end it can be said that drugs is a powerful substances that people use in order to prevent their illness. It has a positive and negative effect to the body. The positive effect is that it reduces illness while allergic reactions for negative effect. This essay helps me fully understand the importance of drugs, also helps me to understand the difference between adverse effects of drugs and its interaction, it also help me to discover the various sources of drugs, how it is administered and how it affects the different system in the body.

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