Essay Example on Define pharmacodynamics and pharmacokinetics

These antibiotics may bind to the calcium forming an insoluble substance in the stomach and make body unable to absorb the antibiotic Pickled Cured and Fermented Foods and MAIOs Tyramine rich foods can increase blood pressure among patients taking monoamine oxidase inhibitors MAIOs and certain medications for Parkinson s disease Vitamin K Rich Foods and Warfarin Taking warfarin to maintain a consistent intake of vitamin K and avoid introducing kale spinach and other leafy greens to their diets Vitamin K produces clotting factors that help prevent bleeding but anticoagulants like warfarin exert their effect by inhibiting vitamin K An increased intake of vitamin K can antagonize the anticoagulant effect and prevent Warfarin from working 5 Compare active transport vs passive diffusion Active transport is the process of moving a molecule or ion against the concentration gradient using energy ATP across a plasma membrane Passive diffusion is when small molecules diffuse across a cell membrane from a region of high concentration to one of low concentration 6 How does distribution of drugs through the CNS differ from other systems Diffusion occurs through the blood brain barrier BBB by trans membrane diffusion for drugs to pass through the CNS This is a very specific process that requires molecules to pass through channels Fat soluble substances pass through the BBB while water soluble substance has difficulty passing through The BBB is selective by solubility factors of drugs Drugs must pass through cells rather than between them Drugs that have a high lipid water partition coefficient can penetrate the tightly apposed capillary endothelial cells 7 Explain the P450 cytochrome system 

The P450 cytochrome enzyme system is primarily responsible for the metabolism degradation and elimination of drugs and primarily found in liver cells 8 What is the first pass effect Give an example when this is important The first pass effect is when the concentration of a drug is reduced greatly before it reaches circulation due to the absorption first in the gut and liver thus reducing it s overall effectiveness An example is Morphine 30 Bioavailability because 70 is metabolized via 1st pass effect if taken orally The drug is absorbed from the GI tract and passes into the liver where some drugs are metabolized Only a proportion of the drug reaches the circulation 9 What is half life What is steady state Why do these matter Half life is the time taken for the plasma concentration of a drug to reduce to half its original value For example the half life of Adderall is about 10 hours For every 10 hours half of the previous amount of Adderall in the body disappears IF 10mg of Adderall was taken at 12AM midnight at 10AM 5mg of Adderall will be left in the body Steady state is when the overall intake of a drug is in dynamic equilibrium with its elimination The time taken to reach the steady state is about five times the half life of a drug Maintenance medications must be taken to insure a steady state is kept in place 10 Define the therapeutic window and index Therapeutic window is the range of doses of a drug that produces an effective response without being harmful or causing any significant adverse effects Therapeutic index is a ratio that compares the blood concentration at which a drug becomes toxic and the concentration at which the drug is effective The larger the therapeutic index TI the safer the drug is If the TI is small the difference between the two concentrations is very small the drug must be dosed carefully and the person receiving the drug should be monitored closely for any signs of drug toxicity