NURS 5334 Pharmacology Exam 1

pharmacology study of drugs & their interactions with living systems clinical pharmacology study of drugs in humans Therapeutics (pharmacotherapeutics) the use of drugs to diagnose, prevent, treat disease or prevent pregnancy chemical, generic, and proprietary drug names Chemical name = description of the drug using nomenclature of chemistry Generic name/nonproprietary name = less complex, indicates pharmacological class Brand name/trade/proprietary name = the name under which the drug is marketed (FDA approved) The objective of drug therapy is to provide maximum benefit with minimum harm! agonist, partial agonist, antagonist Agonists= molecules that activate receptors and mimic the body's own regulatory molecules Partial agonists= mimic the action of the body's endogenous regulators and produce responses of moderate intensity Antagonist= block the actions of agonists and body's regulatory molecules by binding to receptor sites drug interaction vs. side effect vs. adverse reaction drug interaction= can occur whenever a patient is taking two or more drugs, may be intended and desired or unintended and undesirable. may occur with foods/other substances as well (grapefruit is super common and increases blood levels of many drugs) side effect=nearly unavoidable secondary drug effect produced at therapeutic doses (ex: GI distress, drowsiness). generally predictable adverse reaction= any noxious, unintended, undesired effect occurring at normal drug doses What properties are important in considering an ideal drug? 1. Effectiveness - most important property a drug can have 2. Safety - drug cannot produce harmful effects 3. Selectivity - drug elicits only the response for which it is given -there is no such thing as a wholly selective drug because all drugs cause side effects -Additional ideal properties: reversible action, predictability, ease of admin (inconvenient dosage time), freedom of drug interactions, low cost, chemical stability (drug sensitivity to heat/cold), simple generic name What factors determine intensity of drug responses? 1. dose and potency 2. pharmacokinetics (absorption, distribution, metabolism, excretion) 3. pharmacodynamics (drug affinity and receptor signaling pathways) 4. patient specific factors (age, disease state, genetics, weight, etc) 5. drug interactions 6. route of administration 7. timing and frequency of administration What are basics of the four main processes that make up pharmacokinetics? 1. Drug absorption: movement of drug from admin site into bloodstream 2. Drug distribution: transportation of drugs into body fluids via bloodstream to various tissues and organs of body 3. Drug metabolism: medication is inactivated and ready for excretion (liver/kidneys) 4. Drug excretion: drug molecules are removed from site of action and eliminated from the body (liver/kidneys) Drug Absorption - factors affecting absorption: GI conditions, water vs fat solube, pt ability to swallow, route -Absorption is enhanced by rapid drug dissolution, high lipid solubility of the drug, large surface area for absorption, and high blood flow at the admin site. -Lipid soluble drugs can cross membranes easily, whereas drugs that are polar or ionized cannot (water soluble) -Rate of absorption determines how soon effects of drug will begin (rate affected by rate of dissolution, high blood flow, lipid solubility will increase rate of absorption) -Amount of absorption determines how intense effects will be Drug distribution Three factors influencing distribution: 1. blood flow to tissues - pt circulation 2. the ability of the drug to exit the vasculature 3. to a lesser extent, the ability of the drug to enter cells -drugs pass between capillary cells rather than through them, so movement into interstitial space is not impeded -in blood brain barrier, drug must pass through cells of capillary wall due to unique tight junctions -only drugs that are lipid soluble or have a transport system can cross the BBB to a significant degree Drug metabolism - biotransformation/chemical alteration of drug structure - mostly taking place in the liver (hepatic drug metabolizing enzymes, P450 complexes) -Kidneys are unable to excrete drugs that are highly lipid soluble so lipid soluble drugs must be converted into water soluble forms via metabolism in the liver Drug excretion -When healthy, kidneys serve to limit the action of drugs - when kidneys are dysfunctional the duration and intensity of drug responses may increase -Steps in urinary excretion 1. glomerular filtration 2. passive tubular reabsorption 3. active tubular secretion -Infants & elders have a limited capacity to excrete drugs due to kidney development/decreased renal fx -Breastmilk: lipid soluble drugs move across easily, other drugs in smaller concentrations but still concerning -Metabolism + excretion= elimination What is the role of the nurse in understanding the time course of drug responses? -there is a direct correlation between therapeutic and toxic responses and the amount of drug present in plasma 1. Correct timing: Nurses must administer medications at the correct times to maintain therapeutic drug levels and avoid peaks and troughs that could lead to toxicity or non therapeutic effects 2. Therapeutic and toxic effects: monitor patients for the desired therapeutic effects of medications. Including understanding the expected time frame for the onset, peak, and duration of the drug's action. also watch for and document any side effects or adverse reactions and know when these are most likely to occur 3. Vulnerable pt: Understanding how the time course of drug responses may vary in populations (elderly, children, pregnant women, those with comorbidities) What is the clinical importance of a drug's therapeutic range? -The objective of drug dosing is to maintain plasma drug levels within the therapeutic range (above minimum effective and below toxic) -drugs with a wider therapeutic range are more easily administered safely -drugs with a narrow therapeutic range need carefully monitored to prevent toxic effects -facilitates patient care by focusing more attention on patients who are on drugs with narrow ranges for s/s of toxicity in case intervention is needed What are the individual factors that affect drug responses and their clinical significance? -small patients need smaller doses than large patients (body surface area AND weight) -infants and older adults are more sensitive to drugs -kidney disease can decrease excretion and should be dosed at reduced amount -liver disease can decrease metabolism and may need to adjust dosing -patients who become tolerant to a drug may need increased doses -genetic variations can alter immune reactions, how drug receptors are structured, how pt responds to drugs Every patient needs to be treated uniquely and all of these factors should be considered! There is no one size fits all! What are basic considerations of drug therapy during pregnancy and breastfeeding? -dosages may need increased during pregnancy d/t increased hepatic metabolism and glomerular filtration -lipid soluble drugs readily cross placenta and into breast milk but all cross to some extent -must balance benefits vs risks but often don't have solid understanding of the risks -most teratogenic effects happen in week 3-8 of pregnancy -avoid drugs when breastfeeding as much as possible -lack reliable data for most drugs about effects on pregnancy What are patient signs and symptoms of hyper and hypovolemia? Hypervolemia: -high BP -edema -tachycardia -increased respiratory rate -crackles in lungs -weight gain Hypovolemia: -dry mucus membranes -weight loss -weak pulses -low BP -dizziness What are the body cells and tissues that most depend on insulin to provide glucose as the main metabolic fuel? insulin is the key that allows for glucose to enter cells 1. stimulates cellular uptake of glucose, amino acids, nucleotides, potassium 2. promotes conversion of glucose into glycogen in liver key cells using glucose = muscle, liver, adipose tissue What are patient signs and symptoms of hyper and hypoglycemia? Hyperglycemia: -polydipsia -polyphagia -polyuria Hypoglycemia: -tachycardia -palpitations -sweating -headache -confusion -drowsiness -fatigue -if serious, can lead to convulsions and coma How is fluid balance is regulated physiologically? 1. Osmoregulation: Managed by ADH, controlling water reabsorption in the kidneys 2. Volume regulation: Managed by the RAAS, aldosterone, and natriuretic peptides, controlling sodium and water balance 3. Thirst mechanism: Driven by osmolarity and blood volume changes that encourage fluid intake 4. Baroreceptor reflex: Maintains blood pressure and volume through neural and hormonal responses What is the impact of diuretic side effects on nursing care of patients? 1. risk for electrolyte imbalances -monitor lab values and stay aware of signs of imbalances, especially potassium -monitor cardiac function for potential potassium imbalance 2. risk for hypotension/dehydration -monitor blood pressure and vital signs, have patients get up slowly if hypotensive 3. monitor daily weights, edema, Is&Os to assess for changes in fluid balance 4. monitor for hyperglycemia in patients with diabetes using FSBS and educate patients on changes associated with diuretics What are the physiologic effects of insulin on carbohydrate, lipid, and protein metabolism? Carbohydrates: -glycogen converted into glucose when in catabolic state -increase glucose uptake, oxidation, storage -increase gluconeogenesis in liver Lipids: -lipids converted into glycerol and free fatty acids in catabolic state -increase synthesis of triglycerides in adipose tissue Protein: -proteins degraded into amino acids when in catabolic state -insulin increases uptake of amino acids, release of amino acids, and protein synthesis in muscle We have an expert-written solution to this problem! What is glycosylated hemoglobin (hemoglobin A1c) and the clinical importance for nurses? -hemoglobin A1C should be measured every 3-6 months to monitor longterm glycemic control -diabetes is diagnosed if = 6.5% 1. monitor for risk of complications: Higher Hgb A1c levels are associated with an increased risk of diabetes-related complications, such as cardiovascular disease, neuropathy, nephropathy, and retinopathy 2. monitoring disease progression: By tracking changes in Hgb A1c over time, nurses can help identify patients who may be at higher risk for complications and require more intensive management 3. inform patient education and necessary changes to treatment plan Loop diuretics: therapeutic uses, adverse effects, nursing implications and any special safety considerations or points of emphasis for patient education Examples (most end in "semide"): furosemide (Lasix) budesonide (Bumex) torsemide (Demadex) -before administering: assess BP and electrolyte values -works by blocking the reabsorption of sodium and chloride in the loop of Henle, thus not reabsorbing extra water -contraindicated: hypotension and hypokalemia -Administer loop diuretics early in the day to prevent nocturia and improve patient compliance -oral or IV -can be used in pt with low GFR -adverse effects: dehydration, hypotension, hypokalemia, ototoxicity -Watch for signs of dehydration, such as dry mucous membranes, poor skin turgor, and decreased urine output -Nursing actions: 1. Loop diuretics can cause significant potassium loss. Nurses should monitor serum potassium levels to prevent hypokalemia 2. Assessing Renal Function and Fluid Balance: Regularly check renal function tests to ensure the kidneys are not adversely affected by the diuretic therapy, monitor intake and output to assess fluid status and detect early signs of dehydration or fluid overload 3. Monitoring blood pressure to prevent hypotension 4. Daily weights: Weigh the patient daily to monitor fluid status 5. Monitoring for ototoxicity: at high doses or with rapid intravenous administration can cause ototoxicity Thiazide diuretics: therapeutic uses, adverse effects, nursing implications and any special safety considerations or points of emphasis for patient education Examples (most end in "thiazide"): hydrochlorothiazide (HCTZ) most common chlorothiazide (Diuril) metolazone (Zaroxolyn) chlorthalidone (Thalitone) -first line treatment for primary hypertension -work by blocking sodium and H2O reabsorption early in the distal convoluted loop -potassium wasting, not as effective at diuresis as loop diuretics -all thiazide diuretics are PO Assess: renal function, daily weights, edema, BP, potassium levels Risks: hypotension, hypokalemia, dehydration Caution in use: 1. Diabetes: Thiazide diuretics can increase blood glucose levels, so monitor blood sugar levels in diabetic patients 2. Gout: Thiazides can increase uric acid levels, potentially exacerbating gout. Monitor uric acid levels and watch for signs of gout 3. Renal impairment Potassium sparing diuretics: therapeutic uses, adverse effects, nursing implications and any special safety considerations or points of emphasis for patient education spironolactone (Aldactone) MoA: blocks action of aldosterone in the distal tubule in nephron uses: hypertension and edema. Commonly used in combination with a thiazide or loop diuretic to prevent hypokalemia -minimal diuretic effect on its own assess for: potassium levels (HOLD if K+5.0mEq), edema, daily weights, fluid balance cues adverse effects: endocrine-hormonal changes (gynecomastia, menstrual irregularities, impotence, hirsutism, deepening of voice), hyperkalemia nursing implications: 1. nurses should wear gloves and gown when crushing the tablet as it can be hazardous to providers 2. do not administer to pregnant/breastfeeding women patient education: 1. avoid excessive use of salt-substitutes (often high in potassium) or potassium supplements, foods high in K+ Potassium Chloride: therapeutic uses, adverse effects, nursing implications and any special safety considerations or points of emphasis for patient education normal K+ value is 3.5 to 5.0 mEq/L HYPOkalemia= K+3.5mEq/L s/s: weakness, fatigue, muscle cramping tx: replace IV continuous KCl or PO HYPERkalemia= K+5.0mEq/L s/s: peaked T waves, arrhythmias, long PR intervals tx: hold K+ in diet (and supplements, salt-substitutes), hold K+ sparing diuretics, insulin, kayexalate, calcium gluconate, dialysis if severe nursing implications: NEVER IV PUSH K+ check labs and cardiac rhythm Magnesium Sulfate: therapeutic uses, adverse effects, nursing implications and any special safety considerations or points of emphasis for patient education normal Mg++ value is 1.7 to 2.2mg/dL HYPOmagnesemia: Mg1.7mg/dL s/s: hyperexcitable CNS tx: IV or PO magnesium sulfate HYPERmagnesemia: s/s: mild weakness, hypotension, sedation, ECG changes tx: IV calcium nursing implications: check cardiac rhythm and labs Rapid-acting insulin: therapeutic uses, adverse effects, nursing implications and any special safety considerations or points of emphasis for patient education Examples: Insulin lispro (Humalog) Insulin aspart (NovoLog) Insulin glulisine (Apidra) -Onset in 10-30 minutes -Given within 15 minutes before meal -- make sure the tray is ready! -subQ injection or insulin pump infusion -postprandial glycemic control -Clear preparation, can be Nursing implications: -check FSBS before administration -make sure the tray is available before administration -can still be given when patient is NPO for sliding scale coverage (adjusted scale for NPO) Adverse effects: Hypoglycemia or hypokalemia Short-acting insulin: therapeutic uses, adverse effects, nursing implications and any special safety considerations or points of emphasis for patient education Examples: Regular Insulin (Humulin R or Novolin R) -subQ injection, subQ infusion, or IV infusion -given 30 minutes before meals or inpatient settings/emergencies via IV (U-100 strength only in IV) Nursing Implications: -check FSBS before administration -if given with a meal, tray needs to be ready before administering Adverse effects: hypoglycemia, hypokalemia Intermediate-acting insulin: therapeutic uses, adverse effects, nursing implications and any special safety considerations or points of emphasis for patient education Examples: NPH Insulin (Novolin N, Humulin N) -onset in 1-2 hours, duration 12 hours -cloudy suspension -blood sugar control between meals, usually BID (twice a day) -subQ injection -can be mixed in same syringe as fast acting (lispro or aspart) IF clear before cloudy (think "I am gonna be an 'RN'" for Reg-NPH) Nursing implications: -no meal needs to be available, but FSBS should still be checked Adverse effects: hypoglycemia, hypokalemia Long-acting insulin: therapeutic uses, adverse effects, nursing implications and any special safety considerations or points of emphasis for patient education Examples: Insulin glargine (Lantus) Insulin detemir (Levemir) -given subQ daily for basal control and often paired with rapid acting for postprandial coverage with meals -not safe to mix or for IV infusion -onset 2-4 hours, lasts 24 hours Adverse effects: hypoglycemia Nursing implications: check FSBS past 12-24 hour trends before administration to make sure no dips have occurred Oral anti-diabetics/biguanide: therapeutic uses, adverse effects, nursing implications and any special safety considerations or points of emphasis for patient education Example: metformin (Glucophage, Fortamet) -decreases glucose production by the liver and increases the tissue response to insulin adverse effects: GI symptoms (low appetite, nausea, diarrhea), lactic acidosis, decreased absorption of B12 and folic acid, weight loss with low appetite nursing implications: -avoid during hospital stay usually, as it needs to be held for 48 hours before contrast studies and renal function checked after (iodine dye increases risk of lactic acidosis)