​D.1.1 List the effects of medicines and drugs on the functioning of the body.


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Definition of a Drug:
A Drug is any substance that alters normal bodily function when absorbed into the body of a living organism.
Drugs have two classifications:
  • medicinal (pharmaceutical)
  • recreational

Definition of Medicine
A Medicine is any substance or combination of substances which may be administered to human beings or animals with the intent of making a diagnosis or to restoring, correcting or modifying physiological functions in human beings or animals. - Medicine Act (http://genome.wellcome.ac.uk/doc_WTD020943.html)

NOTE: A Medicine is classified as a Drug, but not all drugs are medicines

Medicines can be obtained:
  • In a hospital or pharmacy
  • by a practitioner (prescribed medicine to be picked up at a pharmacy)
  • through supply or retail sale of product (over the counter drugs)
  • illegally

Effects
Generally, a medicine or drug is any chemical that alters one or more of the following:
  • the physiological state, including consciousness, activity level or coordination
  • incoming sensory sensations
  • mood or emotions

NOTE: It is important to remember that the body has natural healing processes that should be given the opportunity to occur.
Also, the Placebo Effect (See below) should be considered when assessing the effectiveness of a drug/medicine.


Examples of effects of medicine:
  • Encourage the production of substances that may be deficient.
    • E.g. Iodine, for hypo-thyroid (disorder)
  • Change the way that cells work in your body.
    • Can occur by influencing the enzymes secreted by cells in the body.
      • An enzyme is a protein catalyst which speeds up chemical reactions in the body.
      • Drugs which inhibit the function of enzymes are called inhibitors.
      • There are two types of inhibitors: competitive (binds to the active site of the enzyme) or non-competitive (binds to the allosteric site of the enzyme).
    • Drugs that change the way a cell functions are called agonists, they:
      • bind to receptors of a neuron (nerve cell) and triggers a response (active potential) by the cell, changing the way a cell functions.
      • mimics the action of a naturally occurring substance (neurotransmitters).
      • blocks re-uptake (the process in which neurotransmitters are rushed back to the sending neuron after it completed sending its message to the receiving neuron) of a neurotransmitter, which can cause the neuron to be constantly stimulated.
    • Drugs that stop the normal function of cell are called antagonists, they:
      • inhibit a neuron's response by binding onto the receptor's active site or allosteric site so as to dampen out or block the effect of a neurotransmitter.
    • Competitive Inhibition: The inhibitor competes with the substrate to occupy the active site to stop the reaction.
      external image 400px-Competitive_inhibition.svg.png
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    • Non-Competitive Inhibition: When the inhibitor occupies the allosteric site instead of the active site to stop the reaction.The inhibitor does not compete against the substrate for the active site.
      external image 400px-Comp_inhib3.png
      http://static.newworldencyclopedia.org/thumb/7/7f/Comp_inhib3.png/400px-Comp_inhib3.png
  • Replace missing or deficient substances
    • E.g. Daily vitamins
      Insulin
      Insulin
      or other supplements
    • E.g. Insulin for diabetics
  • Destroy abnormal cells that cause cancer
    • E.g. Chemotherapy: attacks cancer cells directly and stops or slows their growth and spread.
    • Biological therapy: helps your body's immune system fight cancer
    • Anti-angiogenic therapy: blocks the growth of new blood vessels to a tumor, which may cut off a tumor's supply of oxygen and nutrients.
  • Interfere with microorganisms (germs) that invade your body, kill bacteria and microorganisms, and prevent them from multiplying
    • E.g. Hand Sanitizer to kill bacteria.
  • The effects of medicine can be influenced by other substances previously taken.
    • E.g. alcohol (ethanol) aids in the uptake of drugs by cells, which may lead to overdose. (Don't take medication if you have drank or are planning on drinking alcohol.)

The Placebo Effect


Definition of Placebo
Placebo is a substance that contains no medication, and it is usually just a sugar tablet.
It is used to be prescribed randomly to a part of test group to determine the effectiveness of the medicine.
Placebo comes from the latin term "placebo", which means "I shall please".
First used in medicine in the 1785, as a derogatory term used to describe very ordinary medicine.

Definition of Placebo Effect
Placebo Effect is The physician's belief in the treatment and the patient's faith in the physician exert a mutually reinforcing effect; the result is a powerful remedy that is almost guaranteed to produce an improvement and sometimes a cure.

Types of Placesbo Effect
Placebos (or nocebos) are classified in two groups: inert and actives.
Inert placebo - are those really devoid of any action, be it pharmacological, surgical, etc..
Active placebos - are those that actually have actions, although these actions are not specific to the disease for which they are administered.
It is said that placebos have a positive effect when the patients report some improvement in their ailments, and a negative effect when the patients report that they are getting worse or that unpleasant side-effects have occurred.
All medicines have both their pharmacological effect and placebo effect.



Example:
A man whom his doctors referred to as “Mr. Wright” was dying from cancer of the lymph nodes. Orange-size tumors had invaded his neck, groin, chest and abdomen, and his doctors had exhausted all available treatments. Nevertheless, Mr. Wright was confident that a new anticancer drug called Krebiozen would cure him, according to a 1957 report by psychologist Bruno Klopfer of the University of California, Los Angeles, entitled “Psychological Variables in Human Cancer."
Mr. Wright was bedridden and fighting for each breath when he received his first injection. But three days later he was cheerfully ambling around the unit, joking with the nurses. Mr. Wright’s tumors had shrunk by half, and after 10 more days of treatment he was discharged from the hospital. And yet the other patients in the hospital who had received Krebiozen showed no improvement.


The placebo test is commonly used during the development of medicines. When testing the effectiveness of a drug, while some test subjects are given the real medicine, others are given a placebo. This acts as a control variable.
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