WEEk 1 - 4

• Pharmacology


  The study of substances that interact with living systems through chemical processes, especially by binding to regulatory molecules and activating or inhibiting normal body processes
• Drug


  Any substance that, when taken into a living organism, may modify one or more of its functions. The effect is beneficial or harmful
• Pharmacotherapeutics


  • The area of pharmacology that refers to the use of specific drugs to prevent, treat, or diagnose a disease
  • Divided into two functional areas: Pharmacokinetics and Pharmacodynamics
• Pharmacokinetics


  The study of how the body absorbs, distributes, and eliminates the drug
• Pharmacodynamics


  The analysis of what the drug does to the body, including the mechanism by which the drug exerts its effect
• Toxicology


  The study of the harmful effects of chemicals
• Pharmacy


  Deals with the preparation and dispensing of medications
• Pharmacogenetics


  Deals with the genetic basis for drug responses, especially variations in drug response from person to person
• Pharmacoepidemiology


  The study of drug effects at a population level
• Pharmacoeconomics


  A branch of health economics that aims to quantify in economic terms the cost and benefits of drugs used therapeutically
• Chemical name


  Refers to the specific compound's structure and is usually fairly long and cumbersome
• Generic name


  Also known as the official or nonproprietary name, tends to be somewhat shorter and is often derived from the chemical name
• Trade name


  Also known as the brand name, is assigned to the compound by the pharmaceutical company and may or may not bear any reference to the chemical and generic terminology
• Generic drugs are cheaper than branded medicines because the cost of research is not included
• Drugs.com and MedlinePlus are reliable websites recommended by the FDA for information about drugs
• Orphan drugs


  May be indicated for only the relatively small population with the disease, fewer than 200,000 people in the US
• Off-label prescribing


  The use of a drug to treat conditions other than those that the drug was originally approved to treat
• Routes of drug administration

  • Oral
  • Sublingual/buccal
  • Rectal
  • Inhalation
  • Injection
  • Topical
  • Transdermal
• Oral route


  • Easy, safe, convenient
  • Limited or erratic absorption of some drugs; chance of first-pass inactivation in liver
• Sublingual/buccal route


  • Rapid onset; not subject to first-pass
  • Drug must be easily absorbed from oral mucosa
• Rectal route


  • Alternative to oral route; local effect on rectal tissues
  • Poor or incomplete absorption, rectal irritation
• Inhalation route


  • Rapid onset, application for respiratory disorders, large surface area for systemic absorption
  • Chance of tissue irritation, patient compliance is sometimes a problem
• Injection route


  • Provides more direct administration to target tissues, rapid onset
  • Chance of infection if sterility is not maintained
• Topical route


  • Local effects on surface of skin
  • Only effective in treating outer layer of skin
• Transdermal route


  • Introduces drug into body without breaking the skin; can provide steady, prolonged delivery via medicated patch
  • Drug must be able to pass through dermal layers intact
• Dose-response curve


  Provides information about the dosage range over which the drug is effective, as well as the peak response that can be expected from the drug
• Potency


  Related to the dose that produces a given response in a specific amplitude
• Median effective dose (ED50)

  The dose at which 50 percent of the population responds to the drug in a specified manner
• Median toxic dose (TD50)

  The dose at which 50 percent of the group exhibits the adverse effect
• Median lethal dose (LD50)

  In animal studies, the dose that causes death in 50 percent of the animals studied
• Therapeutic index (TI)


  Calculated as TD50 ÷ ED50, the greater the value the safer the drug is considered to be
• Acetaminophen has a therapeutic index of 27, meperidine (Demerol) has a TI of 8, and diazepam (Valium) has a TI of 3
• Bioavailability


  The extent to which the drug reaches the systemic circulation, expressed as the percentage of the drug administered that reaches the bloodstream
• Membrane structure and function

  The lipid bilayer that composes the basic structure of the cell membrane acts as a water barrier, and drugs often need to cross one or more of these membrane barriers to reach the target site
• Cell membrane


  • The lipid bilayer acts as a water barrier, lipid-soluble compounds can pass directly through the membrane, non-lipid-soluble substances can pass through membrane pores
• Ways drugs and other substances pass through biological membranes

  • Passive diffusion
  • Active transport
  • Facilitated diffusion
  • Cytosis process such as endocytosis
• Passive diffusion


  Drugs and other substances will pass through a membrane if there is a concentration gradient and the membrane is permeable to the diffusing substance
• Effect of ionization on lipid diffusion


  Drugs will diffuse more readily through the lipid layer if they are in their neutral, nonionized form, ionization decreases their lipid solubility
• Diffusion trapping


  It is often desirable for the drug to remain ionized while in the urine so that the body will excrete the drug, if the drug becomes nonionized it may be reabsorbed back into the body
• Diffusion between cell junctions

  In some locations, cells form tight junctions and the primary way a drug may diffuse across the barrier is by diffusing into and out of the cells comprising the barrier