PHARMACOLOGY COMPREHENSIVE REVIEW: NUR312 PHARMACOLOGY: PHARM BASICS

PHARMACOLOGY COMPREHENSIVE REVIEW: NUR312 PHARMACOLOGY: PHARM BASICS • Concepts to Understand How do drugs exhibit their effects? How long does it take for drugs to work? How do the liver and kidneys influence drug metabolism? BIOLOGICAL EFFICACY • The phrase biological efficacy refers to the ability of a drug to exert its desired therapeutic effects • In other words, how well did the drug work for the patient? • Most drugs work by complex metabolic actions of the liver and kidneys and many variables influence the effects of the drug on the body and the effects of the body on the drug BIOAVAILABILITY: • Refers to the ability of drugs to exert their effect • It involves physiological concepts such as reaching the target cell PHARMACOKINETICS • The term pharmacokinetics refers to the effect that the body has on the drug • It involves the movement of the drug, which influences the manner in which a drug behaves in the body over time • It involves the phases of absorption, distribution, metabolism, and elimination • Conditions such as renal and hepatic disease impact this mechanism • It’s essential for nurses to understand this concept so they may identify which drugs might be inappropriate for a patient PHARMACODYNAMICS • The term pharmacodynamics refers to the effect that the drug has on the body • This is influenced by the mechanism of action • The response of the drug is controlled by pharmacodynamics SERENDIPITY • The term serendipity refers to the unexpected clinical effects of a medication • A prime example is Viagra, which was originally created as a antihypertensive, was then marketed for erectile dysfunction when it was discovered to have an effect on this condition • Nurses are in the optimal position to be aware of the unexpected effects of drugs and report them KNOW YOUR “RIGHTS” Rights of Med Administration Patient Medication Dose Route Time Documentation Place Situation NEED TO KNOW LAB VALUES These are the labs you need to know with normal values. • ABGs: pH 7.35-7.45 CO 35-45 HCO3 22-26 • • CBC HCT W (36-45) M (42-52) Hgb W (12-15) M (42-52) WBC 5-10k (Questions generally associated with low WBC) PLT 200k-400k (200k=concern) • BUN 5-20 Chloesterol (Total) 200 Glucose 70-100; 120 fasting is indicative of diabetes HgbA1C 4.6%; 7% : indicative of uncontrolled diabetes Potassium 3.5-5 Sodium 135-145 Creatinine 0.6-1.2 PTT, APTT 25-35 sec for non-therapy and 2xs for normal on therapy INR 2-3 Coumadin; 0.8-1.2 not on coumadin NEED-TO-KNOW PHARM TERMS • The therapeutic effect is the desired response or outcome of administering a drug • The term mechanism of action refers to the process that the drug uses to produce the desired therapeutic effect • Indications are situations in which use of the drug is considered appropriate; or simply the approved reasons to use the drug • Off-label use describes a situation in which use of the drug is not considered an indication (or approved use) but may be effective in certain cases • Contraindications are situations in which the drug should not be administered. For example, heparin, a powerful anticoagulant that’s given to prevent blood clots from forming, should be withheld in a patient who suffered a recent fall as it can increase the risk of hemorrhage. Therefore, a recent fall is a contraindication of heparin • Onset of action refers to the duration of time it takes for the drug to exert its effects following administration. In regards to drugs with a high addictive risk profile (risk for addiction), those with shorter half-lives are more likely to be abused • The term half-life refers to the amount of time that it takes for a drug to be metabolized half-way. This concept can often be used to predict how long it takes for a drug to work, exert its full effect, and last in the system. For example, • Peak action refers to the period of time in which a drug exerts the most powerful effects. This is the duration in which the patient is at the greatest risk of side-effects. Example: When administering insulin, the nurse must be extra-vigilant in monitoring for signs of hypoglycemia during the period of time marked by the peak-action • First-pass effect/metabolism is the effect that the hepatic system has on the drug, which is often metabolized by into a different chemical form. This mechanism impacts the use of various drugs, including the route of administration (such as IV over oral). For instance, some substances are broken down completely as they’re metabolized via the oral route, and therefore rendered ineffective by the time they reach systemic circulation (the blood stream); so they’re only given by IV. The first-pass effect is also manipulated to make draw upon the effects of the by-product that’s produced after a substance is metabolized (the by-product is what’s effective). Hepatic function is required for many drugs to exert the desired therapeutic effect • A drug monograph is a summary of a medication that includes key points that describe how it works, uses (indications), and how to administer it HOW DRUGS ARE NAMED Chemical Names • Chemical names are assigned by the International Union of Pure and Applied Chemistry (IUPAC) • Chemical names are usually extremely long and complex Trade Names- almost always capitalized • Trade names are assigned by the pharmacological company that is marketing the drug for sale • The trade names is often easy to pronounce (“catchy”) and may be influenced by more by marketing concepts (designed to elicit a certain thought or feeling) rather than pharmacological ones Generic Names • Generic names are assigned by the U.S.Adopted Name Council • Following expiration of the patent, other companies are free to manufacture generic versions of the drug • Generic names are generally not capitalized SYSTEMS OF MEASUREMENT Metric Measurement • Volume: Liters (L) or milliliters (mL) • Cubic centimeter (cc is the abbreviation, although it is no longer recommended for use, due to risks of errors) • Weight: Kilograms (kg), grams (g), micrograms (the abbreviation is no longer recommended for use, mu) Household Measurement • Ounces (oz) • Tablespoon (Tbs), teaspoon (tsp) • Discourage the use of household items to measure drugs for administration to due inconsistency in size • FDA and Drug Approval THE APPROVAL PROCESS • America has the most stringent drug approval process in the world. Drug approval is overseen by the Federal Drug Administration (FDA). Extensive research must be conducted prior to approval. There are benefits and downfalls to this. There are several phases of approval, including preliminary approval. • Stages of the FDA Approval Process • Preclinical investigation • Clinical investigation • Review of the New Drug Application • Post marketing surveillance DRUG APPROVAL