Pharm week 1

  1. Pharmacology
    - study of drugs & use
  2. Pharmacokinetics
    - what the body does to the drug - drug in and a drug out
  3. Pharmacodinamics
    - what the drug does to the body - therapeutic effect and side effects
  4. Pharmaceutics
    • - science/ engineering of dosage
    • forms ( xl, sr, cr - do not crush)
    • EX - procardia - regular given 3 times a day
    • - procardia xl given once a day
    • - sr - sustained release
    • - cr - controlled release
  5. Toxicology
    - toxicity is a function of the dose, not the substance
  6. Pharmacokinetics - <PK> four phases
    • a) A – Absorption - IN
    • b) D- Distribution –IN
    • c) M – Metabolism – OUT –
    • primary organ = liver - unless told otherwise
    • d) E- Excretion - OUT – primary organ = kidneys – unless told otherwise
  7. PK -Absorption
    Absorption – process of drug entering the bloodstream – IV route bypasses this

    IV rouse is quick – useful in emergency situations – also more exact than other routes – absorption process can alter amt of drug that gets to blood stream
  8. PK - Distribution
    • Distribution – transport of agents throughout the body after they are absorbed - area under the curve –drugs to not distribute to all tissues equally –
    • hydrophillic (likes water – wants to stay in BS) vs. lipophilic (likes lipids – neurons - cross into breast milk (fatty) and placenta, BBB)

    For an antibiotic to kill bacteria enough of the drug has to get to it – antibiotics are chosen based on what tissues it can cross into
  9. PK - Metabolism
    Metabolism –biotransformation - process used by the body to chemically change a drug molecule - Enzymatic process – leads to deactivation of drug and/or making the drug more water soluble (prep for excretion)

    Enzymes – cytochrome p450 enzymes- hepanic enzymes – metabolic enzymes of PK
  10. Enzyme inhibition
    • – Drug “B” gets in the way of drug “A” – drug A not being
    • metabolized as quickly and builds up in the body – risk for toxicity

    • Intake questions – How many prescribed meds? How many OTC? How many Herbal/ alternative?
    • Tagamet – (for stomach )dollar store – enzyme inhibitor. Recreational drugs?
  11. Enzyme induction
    • – drug “B” increases the number of enzymes that metabolize drug “A” – more enzymes available – drugs leave body quicker that should – St. Johns wart, ginco balboa – eating smoky foods more than three times a week –
    • Antibiotics are inducers
  12. PK - Excretion
    – kidneys produce concentrated urine –

    • BUN & Creatine – both waste products that can be measured in blood panel – increase in BUN or
    • Creatin in blood = decrease in renal function & decrease in some drugs rate of leaving the body

    BUN & Creatine should be measured on 8-12 hr fast – protein intake can alter results
  13. Patient Education forTherapeutic Window/ Range
    • Patient Education for Therapeutic Window/ Range
    • -Keep lab appointments
    • -Don’t double dose – too much anti-epileptic can cause more seizures
    • -Take at same time each day
    • -Try to get locally
  14. Half life
    . Half life < T ½ >- amt of time it takes a drug Cp (concentration in plasma) to decrease by half – serial halfing

    • IV Bolus – 100 mg/ L – Half life is 2 hours – 50-25-12.5- 6.25
    • At 5 x T ½ the dugs is considerend gone from the body –
    • multiply T ½ x 5 to know when drug is gone from body

    All drugs have their own halflife

    Can be effected by inducers and inhibiters
  15. First Pass Effect
    • First Pass Effect – PO drugs only – liver could remove significant amount of drug before it gets to BS
    • – PO dose will be higher than IV dose – right dose for right route

    Morphine has high first pass effect 60mg PO = 10 mg IV
  16. What do the following graphs look like?
    • CP vs T graph
    • Induction
    • Ihibited
    • IV bolus
    • Extended release & ER if cushed
    • Loating Dose
    • Multible doses
    • Therapeutic range
  17. Therapeutic Range
    The range in which the drug produces its defied therapeutic aciton. After peeking, the durg plasma level slowly begins to fall out of the therapeitic range due to excretion process

    A dose higher than the therapeutic range might cause the plasma to reach toxic concentration

    A dose lower than the therapeutic range will have no effect on the body
Author
cswett
ID
129764
Card Set
Pharm week 1
Description
Pharm week 1 Pharmacokinetics, Pharmacodynamics, Pharmaceutics - Ch 4, 5, 23
Updated