NR508 Midterm Outline complete testbank

NR508 Midterm Outline Chapter 1: The Role of the Advanced Practice Nurse as Prescriber Roles and responsibilities of APRN prescribers • The responsibility for the final decision on which drug to use and how to use it is in the hands of the APRN prescriber. • The degree of autonomy in this role and the breadth of drugs that can be prescribed vary from state to state based on the nurse practice act of that state. Clinical judgement in Prescribing • Prescribing drug results from o clinical judgment based on a thorough assessment of the patient and the patient's environment, o the determination of medical and nursing diagnoses, o a review of potential alternative therapies, o specific knowledge about the drug chosen and the disease process it is designed to treat Collaboration with other providers • collaborate with physicians, pharmacists, podiatrists, mental health specialists, therapists, and other providers, including APRNs who are not NPs, physician assistants (PAs), and other nurses. Autonomy and Prescriptive authority • More states are broadening and expanding the legal, reimbursement, and prescriptive authority to practice for all APRNs, including NPs. Chapter 2: Review of Basic Principles of Pharmacology How Drugs are Developed Preclinical Stage: Identification of promising drugs and their testing in animals • Medicinal chemists - new chemical compounds. • Preclinical studies are performed on cells, isolated tissues and organs, laboratory animals • FDA Approval: Drugs approved by the FDA must be both safe and effective. Screened by pharmacologists, toxicologists Clinical Stage: The safety and effectiveness of new products in humans must be established. • Phase I Clinical Trials: Establish biological effects, safe dosages, and pharmacokinetics in a small number of healthy patients. • Phase II Clinical Trials: New drugs are used to treat disease in a small number of patients and to determine the potential of the drug to improve patient outcomes. If the drug looks promising phase III will occur. • Phase III Clinical Trials: Comparison of the new medication to the standard therapy in a larger number of patients at various sites across the country. New drugs must be at least as good or better than other available drugs. Post-Marketing Surveillance: Health professionals- report adverse events --more people receive the drug than in the clinical trials, and sometimes much more is learned about additional adverse effects that occur infrequently with use of the drug. Drug Responses • before a drug can produce a response it must first overcome homeostasis • Dose-Response Curves provide information on the relationship between dosage or concentration and responses for one or more drugs. o Graphs showing drug responses will show the response on the vertical axis and the concentration or dose on the horizontal axis. • Quantal Responses: May or may not occur. For example, seizures occur or they do not. A rash occurs or it does not. A response that is either occurring or absent. o Prediction of drug dosages or blood levels that produce quantal effects is more reliable for a population of patients than for an individual patient. o Data from a population of patients is used to establish appropriate doses or blood levels to predict quantal effects in a large number of patients. Drug examples: oral contraceptives and seizure medications. • Graded Responses: Biological effects that can be measured continually up to the maximum responding capacity of the biological system. o Most drug responses are graded. For example, changes in BP are measured in mmHg, and patients may experience small or large changes in BP following treatment with drugs. If the patient’s BP is too high or too low, we can adjust the dosage based on the patient’s individualized response to the medication. Examples: BP, HR, diuresis, bronchodilation, pain scale 1-10). • Potency: Difference in concentration or dosage of different drugs required to produce a similar effect. o Drugs that are more potent require a lower dosage or concentration to produce the same response. o For example, compare doses of non- prescription drugs that relieve headache: 200 mg ibuprofen, 325 mg aspirin, and 50 mg ketoprofen. Because ketoprofen requires the lowest dose, it has the highest potency. • Efficacy: Expresses the ability of a drug to produce a maximum effect at any dosage. o There are many drugs that will relieve mild pain. No matter how high we increase the dosage, drugs that work well for mild to moderate pain are usually ineffective for treating more severe cancer-related pain, for example. o Treatment of severe pain requires the use of stronger drugs, such as the opioid analgesics morphine or oxycodone. Morphine or oxycodone have higher efficacy for pain relief than ibuprofen. o Drugs with high efficacy can produce greater effects than lower-efficacy drugs can. • Intrinsic Activity: The ability of a drug to produce a response once it has occupied specific receptors. o some drugs produce the maximum receptor stimulation once they occupy receptors; their response is limited by how many drug molecules occupy receptor sites. o Other drugs with lower intrinsic activity can occupy the same number of receptors but will produce a lesser response. o Drugs can also occupy receptors and produce no receptor stimulation; they merely block the action of neurotransmitters or other drugs. • Drug Selectivity: A ratio of the dose or concentration producing the undesired effect to the dose or concentration producing the desired effect. o This is the same as determining how many times the therapeutic dosage needs to be increased to produce the undesired effect. o A medication that requires one tablet to produce the desired response and does not produce undesirable effects unless five tablets are used would have a selectivity ratio of 5. • Therapeutic Index: Ratio of the lethal dose of a drug to the therapeutic dose of a drug. o The therapeutic index of drugs on the market is, of course, always greater than 1; a therapeutic index of less than 1 means that the drug kills before it cures. o The therapeutic index ranges from 2 for some drugs (cancer chemotherapy, lithium carbonate) to 6,000 for others (penicillin in nonallergic patients) • Brand vs. Generic Differences between brand and generic preparations can occur in the inactive ingredients of the tablet or capsule, such as coloring or filler materials. o There are also differences in the speed or rate of absorption. Receptors: agonists, antagonists • Receptors are the large molecules, usually proteins, that interact with and mediate the action of drugs. Receptors are important because they determine the relationship between dose and effect, the selectivity of drugs, and the actions of pharmacological antagonists. • Agonists: Drugs that produce receptor stimulation and a conformational change every time they bind. o Full agonists do not need all of the available receptors to produce a maximum response. Some agonists can produce their maximum response by binding to less than 10% of the available receptors. The receptors that are left over and not needed for a response are called spare receptors. • Partial Agonists: Bind to receptors, but when they occupy the receptor sites, they stimulate only some of the receptors. This is sometimes called intrinsic activity. o they can act as part agonist and part antagonist. o Partial agonists would require all of the available receptors to produce their full response, and the maximum response for a partial agonist is less than that for a full agonist. o The beta blockers acebutolol, penbutolol, and pindolol are partial agonists. Administration can block the effects of adrenergic nerves on heart rate, but partial agonist activity keeps heart rate from falling too low, as might occur following administration of a pure beta-adrenoceptor antagonist • Antagonists: Drugs that occupy receptors without stimulating them. o Antagonists occupy a receptor site and prevent other molecules, such as agonists, from occupying the same site and producing a response. o Antagonists produce no direct response. o The response we see following administration of antagonists results from their inhibiting receptor stimulation by agonists. o For example, beta blockers such as propranolol and atenolol act as antagonists at the beta-adrenoceptor. Adrenergic nerve activity can raise heart rate, and patients with high heart rates experience a significant drop in heart rate following administration of beta blockers. The same administration may have little effect on patients who lack adrenergic nerve activity and already have a lower heart rate. o The effect of antagonists is dependent on the background receptor activity that it can block. o Antagonists produce a shift in the concentration–effect relationship for agonists acting at that same specific receptor as the antagonist; they make agonists for the same receptor appear less potent. o The effect of an antagonist is dependent on its blood levels and its affinity for the receptor. o Most antagonists in clinical use are competitive reversible antagonists, and it is possible to overcome the antagonist effects with higher concentrations of the competing agonist. o A very small number of antagonist drugs (e.g., echothiophate, phenoxybenzamine) act by irreversibly binding to the receptor; their antagonism remains until new receptors can be produced by the cell. Pharmacokinetics Absorption