Pharmacology

• Pharmokinetics is the study of the rate and extent of drug absorption, distribution, metabolism, and excretion
• Pharmodynamics is the study of the relationship between the pharmacologic and physiologic effects of a drug, it is what the drugs do to the body
• The drug absorption rate is bringing a drug into the bloodstream from the GI tract, it is systemic circulation
• Advantages of the oral drug route are that it is quick and easy to administer, it Is cheap and easy for patients to take home
• Disadvantages of the oral drug route are that is is slowly digested, has the first pass effect and can’t be given to unconscious or uncooperative patients
• Advantages of the buccal drug route are avoiding the first pass effect and rapid absorption
• Disadvantages of the buccal drug route are there is a small dose limit and is inconvenient for some
• Advantages of the rectal drug route are bypassing the liver and stomach, good for children who won't swallow pills and can be used when vomiting occurs
• Disadvantages of the rectal drug route are unpleasantness, slow onset and limited dosage
• Advantages of intravenous drug routes are that they are quick and easy to administer, and they can be used to administer large amounts of drug, they are given straight to the bloodstream
• Disadvantages of intravenous drug routes are increased risk of infection and overdose, and the risk of blood clots and artery damage, have to be trained to give
• Intramuscular drug route advantage is that the sustained effect is possible
• Disadvantages of the intramuscular drug route is you need to be trained to give, sometimes have incomplete absorption
• Subcutaneous route advantages are can be self administered and have complete absorption
• Disadvantages of subcutaneous drug route is that it is painful and max 2ml injection
• Advantages of drugs being inhaled are that they are non invasive, rapidly absorbed and avoid first pass effect
• Disadvantages of inhaled drugs are that they can be expensive and can cause side effects, there is also variability in dosage and need training on patients to administer
• The distribution stage of drugs is the process of getting the drug to the other tissues in the body
• Plasma is the part of the blood that carries RBC and WBC around the body, it contains antibodies to fight infection and is 55% of the blood in the body
• Interstitial fluid is the fluid between cells and tissues in the body, it helps bring oxygen and nutrients to cells and remove waste products
• Intracellular fluids are the fluid inside the cell. It is made up of water, ions, and other molecules.
• Free drug molecules are those that can diffuse across biological barriers and through the aqueous compartments of the cell
• A bound drug is a drug that is bound to a protein or lipid or plasma.
• Displacement in drugs means there is a change in free drug amount due to a disconnection of the drug from its original site of action.
• The bioavailability of a drug is the amount of drug that is absorbed into the bloodstream and becomes available at the site of the drug action
• The maximum plasma concentration is reached when drug elimination rate equals absorption rate
• The therapeutic index is the 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 is, the safer the drug is, the drug must be dosed carefully if the therapeutic index is small
• The therapeutic window of a drug is the range of drug dosages which can treat disease effectively without having toxic effects
• Minimum toxic concentration is the concentration of a drug in plasma above which toxic effects are produced
• Minimum effective concentration is the minimum plasma concentration of a drug needed to achieve sufficient drug concentration at the receptors to produce the desired pharmacological response
• Drug metabolism is the process by which a drug is changed into a different form and can be done through oxidation, reduction, hydrolysis and hydration to make the drug easier to excrete
• The liver is dominantly responsible for metbalolisation of drugs
• A pro drug is a pharmacologically inactive medication that is metabolised into a pharmacologically active drug
• Drug metabolites are less active and less toxic than the parent drug usually
• The first pass effect is where a medication undergoes metabolism in a specific location in the body, combined actions of the liver and the gut
• The first pass effect decreases the active drugs concentration upon reaching the site of action
• Enzyme inhibitors are molecules that lower the activity of the enzyme by binding with the active site
• enzyme inducers are molecules that increase the activity of an enzyme by binding to the enzyme or by increasing the synthesis of the enzyme
• Drug excretion is the final stage and is the removal of the drug from the body