NURSING FUNDAMENTALS: PHARMACOLOGY

NURSING FUNDAMENTALS: PHARMACOLOGY Pharmacology - ANS-The study of drugs and their interactions with living systems or the science of drug affects Pharmacotherapeutics - ANS-The desired or therapeutic effect of the drug, the indication for giving a drug Pharmacokinetics - ANS-The study of the changes that occur to the drug while it is inside of the body. Four phases, absorption, distribution, metabolism, excretion Pharmacodynamics - ANS-Effects of the drug on the body How are drugs classified - ANS-According to shared characteristics. Chemical ingredients, physiological effects on the body, therapeutic medications desired effect or use in therapy Enteral - ANS-The G.I. tract is used for ingestion and absorption of drugs(oral,NG,G tube) Parenteral - ANS-Circumvents the G.I. tract, injections, intravenous Topical - ANS-Also bypasses the G.I. tract, includes skin or mucous membranes, installations, irrigations, inhalations What is the first pass effect - ANS-Portion of the med is diverted to liver before it hits the bloodstream metabolism more significant with first dose Advantages of oral route - ANS-Most common, safest, least expensive, subject to the first pass effect, multiple preparations. parenteral route - ANS-Bypasses the G.I. track and avoids the first pass effect, fast absorption rapid onset, breaks skin barrier involves sterile technique, patient anxiety, expensive Advantages of topical route - ANS-Applied to circumscribed area of body, multiple preparations, local or systemic effects, local irritation, always wear gloves when administering, safe disposal of patches What factors affect absorption of a drug - ANS-Route of administration, solubility of the drug, PH and Ionization, blood flow to the site of the drug administration What factors affect distribution of a drug - ANS-Protein binding capabilities of a drug can alter the drugs distribution, blood flow to the target tissues, drugs ability to enter the target tissue through the capillary membrane What factors affect metabolism of a drug - ANS-Drug is converted to a less active form which can be excreted from the body Metabolism occurs primarily in the liver by cytochrome p-450 enzymes Factors that effect metabolism: Liver dysfunction, immature systems (neonates, children) may slow metabolism and pt at increased risk for adverse drug effects Cytochrome P-450 system - ANS--family of enzymes within liver responsible drug metabolism -ethnic variations -drugs and other substances may be either enzyme inducers or inhibitors -drugs affecting p450 are responsible for many drug interactions First pass effect - ANS-Rapid hepatic inactivation of some oral drugs on their first pass through the liver before they reach the systemic circulation. Highly metabolize drugs lose much of their therapeutic effectiveness quickly especially oral medications such as nitroglycerin Highly metabolized, oral medications may be given the another route to bypass the liver Excretion - ANS-Removal of the drug from the body. Factors affecting excretion is age and kidney function. Labs used to valuate kidney functioning food creatinine, B UN, EGFR, creatinine clearance Timing of drug response and effectiveness - ANS-Onset of action; the time needed for a drug concentration to reach a high enough blood level for its affect to appear. Duration of action; the links of time that the drug concentration is sufficient to elicit a pharmacological response. Serum drug level; peak level occurs when the drug is at its highest concentration, trough level occurs when the truck is at its lowest concentration Minimum effective concentration (MEC) - ANS-The concentration of drug which must be present in the body to produce therapeutic effect. Plasma drug levels below the MEC May not produce a therapeutic effect.