Lecture one, units 1 2 pharm


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Lecture one, units 1 2 pharm

  1. 1. + Lecture 1 Units 1 & 2 N307:Pharmacology for Nursing By Juan M Gonzalez BSN, RN
  2. 2. + History of Pharmacology (from Greek words meaning medicine and study)  Began with the use of plants (Herbal Medicine)  Known as “Materia Medica”  Term Pharmacology  1st used in text 1693 (Samuel Dale)  Modern Pharmacology  Fredrick Serturner (morphine from opium) 1805  Injected himself and 3 friends with massive dose… survived it  1st Dept. of Pharm 1847 in Estonia  American Pharm John Jacob Abel  Father of American Pharmacology  1890 1st Pharm Dept in US  University of Michigan
  3. 3. + Nursing & Pharmacology  Pharmacology was developed in the early stages to relieve suffering  To comprehend pharmacology, other areas such as patho and chemistry must be understood  Medications used improperly is the most common cause of harm to our patients  Nurses are the frontline of medication in patients  It‟s not enough to know the medication, you must know the patient  All medications are potentially fatal
  4. 4. + Definitions  Therapeutics  Branch of medicine to relieve suffering and disease prevention  Pharmacotherapy  Application of drugs for disease prevention and relief of suffering  Drug  Chemical agent before it‟s administered  Medication  Chemical agent that has been given  Biologics  Naturally produced agents (hormones, antibodies)  OTC  Over-the-counter  Formulary  List of drugs and their recipes
  5. 5. + Regulations & the FDA  1906- pure food & drug act  1912- Shirley amendment  1938- Food, drug, & cosmetic act (FDA)  1st law preventing sale of non-tested drugs  1988- FDA established (improved)  Agency of the US Dept of Health & Human Services  Center for Drug Evaluation & Research (CDER)  Center for Biologic Evaluation & Research (CBER)  Center for Food Safety & Applied Nutrition (CFSAN)  1994- Dietary supplement health & education act
  6. 6. + FDA  US Dept of Health & Human Services  1988- FDA established as an agency  Center for Drug Evaluation & Research (CDER)  Controls PTC & Rx drugs  Must show safety & efficacy before selling drug  Decides if they are allowed to be used in US  All information should be clear for safe use  ALL Rx MUST get FDA approval to be used in US  Center for Biologic Evaluation & Research (CBER)  Regulations vaccines, blood, & serums  1986- Childhood vaccine act  Center for Food Safety & Applied Nutrition (CFSAN)  Monitors & regulates herbal supplements  These do not have to have FDA approved (1938)
  7. 7. + Approval Stages  4 Phases  1. Preclinical investigation  2. Clinical investigation  3. Review of the New Drug Application (NDA)  4. Postmarketing surveillance
  8. 8. + Preclinical Investigation  Can take up to 3 years  Use of animal studies & cultured cells  Need to try and determine safety  Will it cause harm to humans?  Tested in variety of doses  Actual human risk is not determined  Results are inconclusive
  9. 9. + Clinical Investigation  3 Stages  Clinical Phase trials 1-3  Longest part of approval process  Can take up to 10 years  Average is 5 years  Start with healthy individuals, then large groups with the disease
  10. 10. + Clinical Phase Trials  Phase I  A „new drug application‟ must be submitted before moving to the next stage  An IND (investigational new drug) application may be submitted for Phase I if there is enough evidence to prove safety in humans and there are significant benefits to getting the medication out to the public (cancer, AIDS)  Naming the drug begins here  Phase II  Phase III
  11. 11. + NDA review  Finalizing the „brand name‟ of the drug  Clinical Phase III and animal testing continue depending on results from pre-clinical testing  May take up to 24 months  FDA has 6 months to initially review this by law  Approved- will move to next stage  Rejected- process is suspended until concerns are addressed
  12. 12. + Postmarketing surveillance  Final stage in the FDA approval process  Looking for any harmful effects in a very large population  Looking for adverse effects that take time to be discovered
  13. 13. + FDA Recalls  At any given time, the FDA has the power to pull drugs that have been approved off the market  There must be significant harm to humans before they pull a drug  The benefits must outweigh the risks for any drug
  14. 14. + Recent Changes  Due to the cost ($802 million) to bring a drug to market and the lengthy waiting time for the approval process, the Prescription Drug User Fee act (1992-1996) was negotiated. Over a 5-year period, manufacturers provide a yearly product fee that goes to fund more personnel and restructuring in the approval departments. This decreases the time needed to reach approval status  In 1997, the FDA Modernization Act reauthorized the Prescription Drug User Fee Act  In 2007 the FDA Amendments Act expanded the reform  In 2008 target base revenue for new drugs was over $392 million
  15. 15. + Nursing & Approval Process  Most commonly nurses participate in the approval process during the postmarketing surveillance  In clinical trial phase II & III, nurses monitor for side effects, adverse effects, and therapeutic benefits
  16. 16. + Definitions in Classes and Schedules of Drugs Therapeutic classification Combination drug Pharmacologic classification Bioavailability Mechanism of action Negative formulary list Prototype Dependence Chemical name Withdrawal Generic name Scheduled drugs Trade name Controlled substance
  17. 17. + Classification of Drugs  Therapeutic classification- how it‟s useful in treatment of a disease (usually too broad to really learn the drug)  Pharmacologic classification- the way it works at a molecular or system level (more specific)  See tables 2.1 & 2.2 page 12 in text  Nurses use both of these classifications to learn the drugs, and to monitor their patients‟ safety and benefits from the drugs
  18. 18. + Prototypes  A drug that is well understood in the classification  May be one that is seldom used now due to newer, safer drugs available  If you learn the prototype correctly, you will be able to ascertain outcomes and averse effects of any drug in the same class  Prototypes differ from text to text and source to source
  19. 19. + Drug Names  Combination Drugs  Chemical Name  Has only 1  Names the physical and chemical properties  Very hard to remember most of these  Generic Name  Assigned by the US Adopted Name Council  Usually less complicated than the chemical names  Only 1 generic name  Lower case  Trade Name  Assigned by the company that marketed it  US gives them the rights for 17 years after a NDA is submitted  Helps the developing company get back some of the cost  Also called the product or brand name  Capitalized
  20. 20. + Brand Name or Generic??? Does it really matter?  Dosages may be the same, but the formulary may not be  May have a different „look‟ (tablet, capsule)  Look for the bioavailability of the drug  How long it takes to get to the source of the problem  Inert ingredients can hinder this  Negative Formulary List (Florida)  Can‟t dispense as generic version  Brand Name  For the 1st 17 years, the only available form is the brand name drug  It‟s typically expensive because it has „cornered‟ the market  Generic Name  Less expensive (usually) than brand name  Some can be automatically used in lieu of brand name  No generic if prescription states do not substitute
  21. 21. + Controlled & Scheduled  Scheduled drugs are classified by their potential to be abused  Not all scheduled drugs are controlled  I-V (V has lowest potential of abuse)  II- has a LOT of limitations  I- usually in cancer patients OR research  DEA #s are recorded and monitored as to how much each provider dispenses  Some states are trying to limit the amounts providers and pharmacies can dispense  Controlled is a drug that has restrictions, and requires a „count‟ at the end and beginning of all shifts  Doesn‟t have to be a scheduled medication  Some hospitals count Protonix
  22. 22. + Pharmacokinetics (Definitions) Pharmacokinetics Active Transport Absorption Passive (diffuse) Transport Distribution Affinity Drug-protein Complexes Blood-Brain Barrier Fetal-Placental Barrier Conjugates Cytochrome P-450 Prodrugs Enzyme induction 1st Pass Effect Excretion Minimum Effect Concentration Toxic Concentration Therapeutic range Plasma ½ Life Loading Dose Maintenance Dose
  23. 23. + How the Body Handles Meds  Pharmacokinetics means „medicine‟ & „movement/motion‟  The greatest barrier is crossing membranes  As a drug is taken, it changes formulary each time it crosses a system or membrane  Depending on how the drug enters the body determines which barriers it comes up against  Stomach acid  Liver enzymes  Immune system  If seen as a threat to the body
  24. 24. + Passing Through  Lipid Bilayers  May use other means to produce effects  Bind to receptors  Activate a 2nd messenger within the cell  Impermeable to large molecules/ions & water soluble  Ionized drugs & water soluble drugs  Easily permeated if molecules are small, nonionized, and lipid soluble  Urea, alcohol, water (lipid soluble)  Active Transport  Passive (Diffuse) Transport
  25. 25. + Active transport  the movement of solutes (or molecules) across a plasma membrane from a region of low concentration to a region of high concentration which requires energy.  Think of this as you requiring energy to carry pebbles from the bottom of a mountain up and putting them on a huge pile of pebbles at the top of the mountain.
  26. 26. + Diffuse (Passive) Transport  the movement of solutes down the concentration gradient across a plasma membrane from a region of high concentration to a region of low concentration.  Think of this as flowing down the concentration gradient: going from being crowded to not crowded. The molecule wants space so this is what it will naturally do, so it doesnt take any energy, like a waterfall.
  27. 27. + Medication Absorption  Involves movement from the site of administration, across membranes, to circulating fluids  Can be across skin or membranes  Primary factor determining how long it takes to get an effect of the drug  Speed of absorption depends on form of drug  The critical nature of a patient‟s condition depends on a faster absorption rate of a medication
  28. 28. + Absorption Factors  Dose of medications can affect the rate of absorption  Ionization of the meds  pH of the local environment  Drug-Drug & Food-Drug factors affect it as well
  29. 29. + Absorption in the Lifespan  Pregnancy & Lactation  Hormone changes  Slowed GI motility & increased acidity  Increased respiratory rate  Teratogens  Categories (7.1)  Lactating  Shorter ½ life is best  High protein-binding ability best  Children  IM sites vary on age & muscle mass  Safety containers  Middle-Age  Health-wise is comparable with the young adult until after the age of 45  Elderly  Need lower doing  Polypharmacy is an issue  Higher rate for adverse effects  Slower absorption rate, faster toxicity levels
  30. 30. + Distribution  How the drug (agent) is transported through the body to the system  Factors that can affect this include:  Amount of blood flow to the tissues  Lipid solubility of the med  Type of tissue and affinity  Adipose tissue, bone marrow, teeth, eyes  Calcium salts, lipid-soluble vitamins, valium  Drug-Protein complexes have to be unbound  Competing medications  Barriers  Blood-brain  Fetal-Placental
  31. 31. + Lifespan & Distribution/Metabolism/Excretion  Pregnancy & Lactation  Higher circulating volume  Children  Depending greatly upon development age and maturity of systems  Middle-Age Adult  After 45 y/o, may begin taking multiple meds for Dz  Elderly  Increased body fat leads to more drug storage  Have decrease in plasma levels because of this  Easily dehydrate, increasing toxicity possibility  Aging liver, heart, kidneys
  32. 32. + Metabolism  Chemical conversion of a drug to a form the body can access and then eliminate  Sites of metabolism  Liver  Primary site for majority  Cytochrome P-450 enzyme  Can inactivate a drug to be excreted  Can increase activation of a drug  Prodrugs have no action until they are changed into their active form  Enzyme induction is the increase of metabolic activity in the liver  They need higher doses to reach a beneficial effect  Kidney  Cells
  33. 33. + Metabolism Factors  Age  Elderly and children  Always start low and go slow  Can become toxic easily  First Pass Effect  Oral meds are the biggest problem here  These meds need to be administered in alternate forms if too much of the med is inactivated by the 1st pass (hepatic metabolic reaction)
  34. 34. + Excretion  Removing the drugs from the body  Factors that can affect this:  Renal failure  Liver failure  Sites of excretion  Bile  Biliary secretion can take several weeks  Saliva, sweat, breast milk  Respiratory  Faster the breaths per minute the faster the excretion  Kidneys (most common)  Glomerulus  Renal tubule  Distal tubule of the nephron
  35. 35. + Plasma, ½ Life, Dosing  Therapeutic responses correlate with plasma levels  Minimum effective concentration  Toxic concentration  Therapeutic range  ½ Life  Determines how long a drug stays in circulation  Determines dosing regimen  Loading Dose  Larger than the maintenance dose  To bring up plasma levels  Maintenance Dose  To keep plasma levels at a constant
  36. 36. + Pharmacodynamics  Means „medicine‟ & „change‟  Therapeutic indexes, dose-response relationships, & drug-receptor interactions determine course of treatment  Therapeutic index  Tells us the safety issue in the range of dosing  Median lethal dose (LD50)  Differentiate between toxic and lethal  The higher the LD50 the safer the drug  Dose-response relationship  To find the most beneficial dose at the lowest mg  Potency- the more potent the drug, means a therapeutic effect is reached at a low dose range  Efficacy- MORE important… it works best for the problem  Drug-receptor interaction  Drugs bind to specific receptors  They can stimulate or inhibit  They compete for receptor sites (survival of the fittest)
  37. 37. + Psychosocial, Cultural, & Gender Issues  Holistic Care  Taking into account the entire individual  Psychosocial Influences  It‟s not just about the disease, but how they view themselves spiritually, have hope, and support  Worrying about how other‟s view them  Cultural & Ethnic Influences  Does it go along with their belief system  Does it correlate with their religious practices  Community & Environmental Influences  Financial restraints  Transportation issues  Genetic Influences  Certain ethnicities are predisposed to diseases  Some drugs have been found to either work better or are less than effective depending on the ethnicity  Gender Influences  Men and women are vary different when it comes to medications  Some meds work better for men, others for women  Some side effects of meds effect the genders in ways that will prevent compliance with the regimen