Drug Action Across the Life Span - Nursing Pharmacology PDF

Chapter 3 Drug Action Across the Life Span Clayton’s Basic Pharmacology for Nurses, 19th edition Michelle Willihnganz, MS, RN, CNE Lesson 3.1 Drug Action Across the Life Span (1 of 2) 1. Explain the impact of the placebo effect and the nocebo effect. 2. Identify the importance of drug d...

Chapter 3 Drug Action Across the Life Span Clayton’s Basic Pharmacology for Nurses, 19th edition Michelle Willihnganz, MS, RN, CNE Lesson 3.1 Drug Action Across the Life Span (1 of 2) 1. Explain the impact of the placebo effect and the nocebo effect. 2. Identify the importance of drug dependence and drug accumulation. 3. Discuss the effects of age on drug absorption, distribution, metabolism, and excretion. 4. Explain the gender-specific considerations of drug absorption, distribution, metabolism, and excretion. Lesson 3.1 Drug Action Across the Life Span (2 of 2) 5. Describe where a nurse will find new information about the use of drugs during pregnancy and lactation. 6. Discuss the impact of pregnancy and breastfeeding on drug absorption, distribution, metabolism, and excretion. 7. Discuss the role of genetics and its influence on drug action. How Age  Age and  Infants and the very old tend to be most sensitive to drug effects Body  Aging process brings about changes in body composition and Weight  organ function Body weight Affect  Considerably overweight patients may require an increase in drug Drug dosage to attain the same therapeutic response Therapy  How  Gender Gender  In almost every body system, men and women function and differently; experience disease differently Metabolic  Metabolic rate Rate  Patients with higher-than- Affect average metabolic rate tend to metabolize drugs more rapidly Drug  Chronic smoking enhances metabolism of some drugs Therapy   Illness  Pathologic conditions may alter rate of absorption, distribution, How Illness metabolism, and excretion of drug and  Patients with kidney failure Psychology generally will excrete drugs at a slower rate Affect Drug  Psychology Therapy  Attitudes and expectations play a major role in a patient’s response to therapy; willingness to take medication as prescribed Placebo and Nocebo PLACEBO EFFECT: PATIENT’S NOCEBO EFFECT: PATIENT’S POSITIVE EXPECTATION CAN NEGATIVE EXPECTATIONS CAN POSITIVELY AFFECT THE OUTCOME RESULT IN A LESS-THAN-OPTIMAL OUTCOME   Occurs when a person begins to require a higher dosage of a Drug medication to produce the same effects that a lower dosage once Tolerance  provided Can be caused by psychological dependence   Person is unable to control his/her ingestion of drugs  Physiologic: Person develops Drug withdrawal symptoms if drug is Dependence withdrawn  Psychological: Person is emotionally attached to a drug   Drug accumulation occurs when the next dose is given before the previously given drug has been Cumulative metabolized or excreted  May result in drug toxicity Effect  Carcinogenicity: Ability of a drug to induce living cells to mutate and become cancerous Factors That Influence Absorption (1 of 4)  Absorption: Process by which drugs are absorbed in the body; most common is via GI tract; other routes are parenteral and topical  Age  Premature infants: Slower gastric emptying time may allow increased absorption  Factors That  Age Influence  Neonates: IM absorption erratic, reduced gastric acidity Absorptio  Infants: Topical absorption increased n (2 of 4)   Geriatric patients  IM absorption erratic Factors  Reduced salivary flow makes That  swallowing difficult Transdermal absorption hard to Influence  predict Timed-release/enteric-coated Absorptio tablets cannot be crushed  n Reduced GI acidity affects absorption (3 of 4)   Slower gastric emptying time Decreased GI motility and blood flow   Gender Factors  A woman’s stomach empties That solids more slowly than a man’s does Influence  Slower gastric emptying time may allow drug to stay in contact Absorptio with absorptive tissue longer n  Body weight may aggravate the higher blood alcohol level and (4 of 4) state of intoxication in women and men   Distribution: Ways in which drugs are transported to site of action Factors  Depends on pH, body water concentrations, fat tissues, That protein binding, cardiac output, and blood flow Influence  Infants Distributio  Higher total body water content, n requiring higher dose on mg/kg basis (1 of 2)  Lower body fat  Reduced protein binding in neonates  Factors That  Geriatric patients: Total body Influence water content decreases Distributio  Gender: Total body fat higher in females n (2 of 2)   Metabolism: Process whereby the body inactivates medications; primarily occurs in Factors the liver  Infants: Enzymes take several That weeks to a year to develop Influence  Older adults: Liver cells Metabolism decrease, blood flow decreases  All ages: Genetics, smoking, diet, other medications, liver disorders  Factors  That Drug metabolites and the drug itself are excreted from the body Influence  Preterm infants have 15% of the renal capacity of an adult Excretio  Neonates have 35%  Full adult function occurs at 9 to n 12 months (1 of 2)  Factors  Geriatric That  Decreased renal blood flow Influence   Reduced cardiac output Loss of glomeruli Excretio  Decreased tubular function n  Serum creatinine levels give estimate of renal function (2 of 2) Therapeutic Drug Monitoring  Measurements of drug concentration in blood sample  Very essential in neonates, infants, children  Dosage and frequency of medications can be adjusted to maintain therapeutic level of potentially toxic drugs Monitoring Parameters All medicines have a Crucial that normal number of parameters, values for monitoring expected therapeutic parameters and actions, common laboratory tests be adverse effects, serious related to the age of the adverse effects, and any patient being monitored drug interactions Pediatric Patients Dosage Measure liquid adjustments Use appropriate medications expected dilution using mL during growth Aspirin use Allergic Verify dosage linked with reactions occur prior to giving Reye’s rapidly in syndrome children Geriatric Patients (1 of 2) Complete a thorough drug history, including Evaluate vision and prescription, OTC, motor skills herbal medications, and nutritional status When evaluating a new symptom, determine Start with smaller whether it was induced doses and gradually by a medication increase already prescribed Geriatric Patients (2 of 2) Keep multidrug regimen simple Review if any medications can be discontinued Assess ability to pay for medications Polypharmacy: Multidrug therapy Potentially Inappropriate Medications for Geriatric Patients Includes medications that should be avoided Some are considered and those that are rarely appropriate to give only appropriate: Some with certain indications barbiturates, but may have potentially benzodiazepines, and adverse reactions some narcotics   Which patient has the greatest Audience percentage of body water? Response a) Older adult b) Middle-aged person Question c) Infant 1 d) Toddler   Which type of topical drug is Audience more readily absorbed by infants? Response a) Fat-soluble Question b) Water-soluble 2 c) d) Emollient Protective   Which form of medication is Audience more easily administered for a toddler who requires a course of Response antibiotics? Question a) Enteric b) Capsules 3 c) Tablets d) Liquid   It is important to maintain Audience therapeutic levels of drugs to avoid the complications of being Response over- or undermedicated. If a Question drug level of 0.5 to 2 ng/mL is considered therapeutic, a drug 4 level of 0.45 ng/mL is considered to be what? a) Toxic b) Therapeutic c) Subtherapeutic d) Tolerant   Due to the decreased protein- Audience binding capacity in preterm infants, what adjustment in Response dosage of protein-binding drugs Question would need to made? a) The dosage should be 5 decreased. b) The dosage should be increased. c) The dosage should be kept at the same level. d) Protein-binding drugs are not administered to infants. Pregnant Patients 1 2 Fetus is exposed to Teratogens: Drugs substances in that cause abnormal mother’s blood development of fetal tissues  Avoid Avoid drugs if at all possible Use of Be When taking woman’s history, be alert to possibility of pregnancy Monitoring Parameters Instruc Instruct patient to avoid drugs, t alcohol, and tobacco : Pregnant Try Try nonpharmacologic treatments before using medicines Women Avoid Avoid herbal medicines Drugs Known to be Teratogenic Androgenic and ACE inhibitors, Thalidomide, estrogenic ethanol, vitamin A, hormones tetracycline warfarin Anticonvulsants Angiotensin II , antimanic Chemotherapy, receptor agents, statins, cocaine antagonists antithyroid Use of Monitoring Parameters: Breastfeeding Infants Take medicine Some drugs are immediately after Discuss all known to enter breastfeeding or just medications with breast milk and harm before infant’s health care provider the nursing infant longest sleeping period Genetics and Drug Metabolism (1 of 2) Genetics: Study of how living organisms inherit the Study traits of their ancestors, including function of metabolic pathways Genome: Complete package of genetic coding of an Complete organism Pharmacogenetics: Study of how drug response may Study vary according to inherited differences Genetics and Drug Metabolism (2 of 2) Significant differences can occur among racial and ethnic groups Most studies to date have concentrated on cardiovascular and psychiatric drugs, analgesics, antihistamines, and ethanol Monoclonal antibodies are early examples of medicines that were synthesized to attack certain types of cancers Questions?