Pharm Chapter 3 Drug Action Across the Life Span

Which factors affect the gastrointestinal absorption of medicines? (Select all that apply.)

Gastric emptying time Enzyme activity Gastric pH Blood flow of the mucous lining of the stomach and intestines

A 63-year-old patient is considered to be in which life stage?

Older adult. The older adult age range is 55 to 64 years. The adult age range is 19 to 54 years. The elderly age range is 65 to 74 years. The aged age range is 75 to 84 years.

Which phenomenon occurs in the body as a person ages?

Lean body mass decreases. With aging, lean body mass and total body water decrease, and total fat content increases. The body weight of a preterm infant may be composed of 1% to 2% fat, whereas a full term newborn may have 15% fat. Adult total body fat ranges from 18% to 36% for men and 33% to 48% for women between the ages of 18 and 35 years. Generally, protein needs are highest at 0 to 6 months of age, then gradually decrease.

A student nurse is preparing to administer a topical medication to a pediatric patient. Which statement by the student indicates a correct understanding about topical drug absorption in this patient?

"Infants wearing plastic coated diapers are more susceptible to skin absorption." Infants wearing plastic coated diapers are more susceptible to skin absorption because the plastic acts as an occlusive dressing that increases hydration of the skin. Topical administration with percutaneous absorption is usually effective in infants because the outer layer of skin is not fully developed. Skin is fully hydrated at this age, and water soluble drugs are readily absorbed. Inflammation actually increases the amount of drug absorbed.

Which factor associated with aging increases the risk of gastric irritation from nonsteroidal anti-inflammatory drugs (NSAIDs) in older adults?

Delayed gastric emptying Premature infants and geriatric patients have a slower gastric emptying time, partly because of their reduced acid secretion. A slower gastric emptying time may allow the drug to stay in contact with the absorptive tissue longer, thereby allowing for increased absorption with a higher serum concentration. There is also the potential for toxicity caused by extended contact time in the stomach for ulcerogenic drugs (e.g., NSAIDs). Decreased splanchnic blood flow has no effect on gastric irritation from NSAIDs. Secretion of gastric acid is decreased, not increased or prolonged, and the pH of the gastric acid is increased in older adults. Loss of cells from the gastric plexus is not a factor associated with gastric irritation from NSAIDs.

A 66-year-old patient is considered to be in which life stage?

Elderly Age 65 to 74 years is considered elderly. The adult age range is 19 to 54 years. The older adult age range is 55 to 64 years. The aged age range is 75 to 84 years.

Women may experience more problems than men when taking aspirin because of a decrease in which factor?

Gastric emptying Generally, a woman's stomach empties solids more slowly than a man's does, and it may have greater gastric acidity, thus slowing the absorption of certain types of medicines (e.g., aspirin). Decreased gastric emptying allows the aspirin to have prolonged contact with the lining of the stomach, causing increased potential for ulceration and increased absorption. The alcohol dehydrogenase enzyme does not affect the absorption of aspirin. Women have greater gastric acidity than men, which may cause delayed drug absorption. Hepatic enzymes do not affect the process of drug absorption.

When initiating drug therapy in elderly adults, prescribed medications are typically started at what range of the normal adult dose, with the amount of medication increasing over time?

One third to one half Start at one third to one half of the normal adult recommended dosage, and then gradually increase the dosage at appropriate intervals to assess for the therapeutic effect and the development of adverse effects. The starting range allows the healthcare provider to assess for therapeutic effects and the development of adverse effects. With measurement over time, the medication dosage for the elderly patient is able to be increased based on therapeutic effects and absence of adverse reactions. One fourth to one third is too low. One eighth to one fourth is also too low. One half to three fourths is too high and may cause adverse reactions in the patient.

When administering medication to an infant, which principle of pharmacokinetics must the nurse keep in mind?

There is an increased risk of toxicity with use of topical agents. Topical administration with percutaneous absorption is usually effective for infants because their outer layer of skin (i.e., the stratum corneum) is not fully developed. Because the skin is more fully hydrated at this age, water soluble drugs are absorbed more readily. Absorption from the gastrointestinal (GI) tract is less predictable in infants than in adults because of rapid GI transit times and variations in gastric pH. Serum protein binding is less, not greater, in infants than in adults. Drugs are excreted, not metabolized, by the kidneys.

In administering medication to a patient with decreased albumin and globulin levels, what concerns the nurse most?

There may be increased free protein-bound drugs available, increasing the potential for adverse drug reactions. Although the total body protein concentration is unaffected, albumin concentrations gradually decrease, and other protein levels (e.g., globulins) increase. As albumin levels diminish, the level of unbound active drug increases. Initial doses of highly protein bound drugs should be reduced and then increased slowly if there is evidence of decreased serum albumin. Lower protein binding may also lead to a greater immediate pharmacologic effect because more active drug is available; however, the duration of action may be reduced because more of the unbound drug is available for metabolism and excretion. Albumin and globulin (plasma proteins) do not affect the absorption of water soluble drugs. Hepatic enzymes, not albumin and globulin (plasma proteins), are involved in the metabolism of a medication. Albumin and globulin (plasma proteins) are not involved in the distribution of lipid soluble drugs.

Which guideline does the nurse follow when administering oral medication to a preschool child?

Using a follow up rinse with a flavored drink. Taste becomes a factor when administering oral liquids because the liquid comes into contact with the taste buds. Using a follow up rinse with a flavored drink helps minimize any unpleasant medication aftertaste. A capsule or tablet should be placed near the back of the tongue. If a child's teeth are loose, chewable tablets should not be used. The preschool child should be allowed to make decisions about how medication is administered. Supporting the head while holding the child in the lap is typically done for infants.