Pharm Quiz: Chapters 4, 5, 6

What are some strategies that nurses can take in preventing adverse effects?

-Assess pt. health history and list of medications -assess bun (blood urea nitrogen) & creatinine clearance (CrCl) - educate patient and family about generic and trade names to prevent overdose - assess therapeutic drug levels as ordered by the prescriber to determine the medication effectiveness and prevention of toxicity

What physiological changes in older adults affect metabolism?

-decrease in hepatic circulation -lower rate of metabolism (Medications with a long half-life will remain in the body for a greater amount of time) - decreased hepatic enzymes (this alter the ability to remove metabolic by-products)

What physiological changes in older adults affect distribution?

-decreased cardiac output -increased body fat -decrease body mass and body fluid -decrease serum albumin

What physiological changes in older adults affect absorption?

-decreased gastric acidity -delayed/lack of absorption -increase gastric pH -decrease blood flow -decrease surface area -diminished gastric emptying -decreased circulation -decrease muscle mass

What physiological changes in older adults influence Excretion?

-decreased renal blood flow -decreased number of functioning nephrons -decreased GFR -decreased tubular secretion -

Medication adherence and aging

-polypharmacy risk increases with age -economic factors: not enough $ to pay for meds -Start low and go slow -If pt. is asymptomatic they discontinue meds because they feel better. Educate the pt. on the importance of taking meds as directed To improve adherence: Inexpensive, use generic brand, easy to follow, as few doses as possible

Main Points

-water soluble drugs lead to lower drug levels in infants than adults. In contrast, protein bound drugs that lead to increased drug levels -Drug metabolism and excretion is decreased in infants compared with adults because of immature hepatic and renal function -Effects of drugs are longer and stronger infants than in adults because of delayed gastric emptying and reduced gastric acidity.

What is the maximum dose of digoxin (Lanoxin) a patient with heart disease should receiver per day? why?

0.125 mg per day. Digoxin has a low therapeutic index placing patients at risk for adverse effects.

Why do prescribers avoid the use of IM injections in pediatric patients?

1. The associated pain 2. Unpredictable absorption due to low blood flow to skeletal muscles and weak muscle contractions. these factors contribute to the erratic absorption of IM injections.

Beers Criteria: what is it?

A list of potentially inappropriate medication used by the older adult population in 1997. The list confirms toxic medication effects and drug-related problems affect the safety of older adults and names drugs that cause problems in this population.

What are some factors that affect the absorption of drugs in pediatrics?

Age of the child gastric emptying intestinal motility routes of administration skin permeability

Name 5 drugs on the Beers list and it's primary side effect

Amiodarone (Cordarone): altered QT interval Cimetidine (Tagamet): confusion Digoxin (Lanoxin): digoxin toxicity Flurazepam hydrochloride (Dalmane): sedation Methyldopa ( Apo-methyldopa: Aldomet) : bradycardia, depression

Nursing Process

Assess: pts. knowledge, med use & action, adverse effects, goal of therapy, dosage & administration physiological status: Renal/liver/cardiovascular function, physiological changes, pts. ability to maintain adherence to meds, memory, ability to care for self Diagnoses: effective therapeutic regimen management risk for falls ineffective health maintenance readiness to learn planning/goals: pt. will : tak meds as prescribed, tolerate meds based on renal/liver function, report any adverse effects, maintain adherence Nursing interventions: assess pt, liver/renal function, assess pts. response to med regime, instruct pts and fam about med admin Evaluation: pts. response ot med regime, pt & fam understanding, pt. adherence to medication regime

How do you calculate Body Surface Area (BSA)?

BSA (m2) = the square root of: Body weight (kg) -body height (cm) divided by 3600 The equation is on pg 70 in clinical drug therapy

How does the amount of body fluid affect drug distribution?

Body fluid decreases in proportion to total body weight. It can increase the risk of toxicity because drug concentrations of water soluble drug concentrations are greater.

How do responses to drug therapy differ in various ethnic/racial populations?

Caucasian Americans & African Americans: poor metabolizer of medications Asian Americans: metabolize and excrete medications more quickly.

How do you estimate a CrCl?

CrCl (mL/min)= (140-age) x (body weight in kg) divided by (72x serum creatinine in mg/dL)

What are some causes of pharmacodynamics variability?

Differences in body composition Immature systems Genetic make up total body water fat stores changing amounts of protein throughout childhood these factors influence the effectiveness of the drug

Where does excretion occur? Where does elimination occur?

Excretion occurs via the kidneys and elimination is the urine follows

Medication administration: School-age/ adolescents

Explain procedure in more detail Pt. is allowed to take meds independently but needs supervision Educate on safety Self care related to medication administration is a good teaching point for adolescents. They should be made aware of self-care

Medication administration: Infants

Focus: Safe calculation, administration, teach parents how to deliver medications correctly -Comfort care is important -IV sites are found in the scalp, hands, or feet -oral medications are administered with dropper or oral syringe

What is the most reliable measure for evaluation of renal function?

GFR

How does an older adults decrease in serum albumin affect drug distribution?

If there is an insufficient amount of serum albumin (many medications require serum albumin, transport, and distribute medications to the target organ) the amount of free drug rises and the effect of the drug is more intense.

How does and infants liver function affect distribution?

Infants have an immature liver function which leads to very low plasma protein levels, which limits the amount of protein binding by drugs.

How can increased body fat affect drug distribution?

Lipid soluble drugs stay in the fat longer. This includes drugs such as anesthetic agents and place older adults at risk for respiratory depression following surgery

How does cardiac output influence drug distribution?

Medication are not distributed adequately due to the decreased circulation and diminished cardiac output.

Ch. 6 Box 6.1 pg. 88

Name 5 Risk category D Evidence of human fetal risk. But the potential benefits may warrant use of the drug in pregnant women despite potential risk. ACE inhibitors ( 2nd & 3rd Trimesters) Antifungals (voriconazole) Antivirals (efavirenz) Mood Stabilizer (lithium) Nicotine replacement products (oral inhaler, nasal spray, transdermal patch) Risk category X Risk clearly out weigh benefits. Studies have demonstrated fetal abnormalities. Anticoagulant (warfarin) Antiviral (ribavirin) Male Sex Hormones (androgens, anabolic steroids0 Nicotine replacement (chewing gum) Female sex hormones (estrogens progestin's, oral contraceptives)

Why are infants at risk for increased drug levels?

Neonates have delayed, irregular gastric emptying and reduced gastric acidity. The delay can lead to greatly increased drug levels. the decreased acidity results in greater absorption of acid-labile medication or reduced absorption of weakly acidic medications.

How do pharmacodynamics variables in pediatric patients differ?

Pediatric patients have immature organ systems as well as changing body compositions causing the drugs to affect children differently.

What is the distribution of drugs in pediatric patients dependent on?

Percentage of body water liver function degree of protein binding development of the blood-brain barrier

What is the concern with a slow absorption rate?

Slow absorption rate can change the peak serum drug levels. The patient may require larger doses to produce therapeutic results

What does a patient's CrCl indicate?

The ability of the renal system to eliminate medications and prevent adverse affects

Why do the drug actions on target cells occur and where do they occur at?

The actions occur because of chemicals binding with the receptors at the cellular level. Most of these receptors are proteins on the surface or within cells

What is the basis of pediatric drug dosing?

The basis of pediatric drug dosing is weight (or body surface area). The dose is dependent on the growth and developmental changes that occur across the lifespan.

What is the blood-brain barrier composed of? What is it's purpose? How does it affect distribution in neonates?

The blood-brain barrier is composed of capillaries with thick bonds in the Central Nervous System. The Blood brain barrier prevents passage of most ions and large molecular weight compounds from the brain to the blood. It protects the CNS, but can make drug deliver to the neurons more difficult. In neonates, the blood-brain barrier is poorly developed; Drugs and other chemicals can easily affect the CNS. Assess for increased drug effects and toxicity. Unwanted CNS effects: dizziness, sedation, seizures

What is the key to preventing cardiovascular disease in patients with hypertension?

The key is controlling blood pressure

Fetal Therapeutics

There are a few drugs that can be given to the mother for therapeutic effects on the fetus: -Digoxin for fetal tachycardia or HF -levothyroxine for hypothyroidism -penicillin for exposure to maternal syphilis and GBS - prenatal betamethasone to promote surfactant production, improving fetal lung function and decrease respiratory distress syndrome in preterm infants

What are some issues with metabolism of drugs for pediatric patients?

They have a low ability to metabolize drugs due to an immature liver. This results in the inability to effectively break down the drugs. The liver matures at the end of two years It is important to monitor for toxicity in infants and young children closely

How does skin affect drug absorption?

Thin and highly permeable skin increases the rate of absorption of topical drugs

Medication administration: Toddler/Pre-schoolers

Toddlers: Mobile & Curious Preschoolers: Inquisitive & controlling Things to remember: short attention spans, independent, involve toddlers and preschoolers (hold an item, choose a band aid) Short and simple explanation Adults need to control administration

How does total body water affect distribution?

With a higher total body water percentage, water soluble drugs (such as atenolol and penicillin) are diluted easily and move into intracellular tissue. Serum drug concentrations are lower, and increased dosages of water-soluble drugs may be necessary to maintain therapeutic drug levels (especially in neonates and premature infants)

Why is it an issue for an infant to have low plasma protein levels?

With low plasma protein levels there is a limited amount of protein binding by drugs which causes the serum concentrations of highly protein-bound drugs ( such as phenytoin, warfarin, and ampicillin) to be higher. This puts the child at risk for toxicity. After the child is one, protein binding ability is a the adult level and its effect on drug distribution is no longer a concern

What are some risks for children and neonates with drug elimination?

Young children have immature kidneys, a reduced glomerular filtration rate, and a slower renal clearance. Neonates are especially prone to increased levels of drugs that are eliminated by the kidneys. Renal function reaches that of an adult between 1-2 years of age

total body water

amount of water within the body (both intracellular and extracellular)

What are the most common health problems in older adults?

arthritis, heart disease, decreased sensory perception, bone disorders, and diabetes mellitus. Older adults are also more prone to antibiotic resistant infections

Blood - brain barrier

barrier in the central nervous system composed of capillaries with tight bonds, which acts to prevent the passage of most ions and large-molecular-weight compounds, including some drugs, from the blood to the brain.

what is the #1 cause of death in adults and older adults?

cardiovascular disease

What impact can decreased muscle mass make in lab results?

decreased muscle mass along with altered circulation can result in abnormal blood concentration

How does diminished gastric emptying affect older adults?

diminished gastric emptying = medication stays in the stomach longer -> which increases the risk of nausea/vomiting -> which promotes fluid volume deficit

How do you calculate a dose for a pediatric patient?

pediatric dose= BSA/1.73 x adult dose Equation is on pg. 71

children

person between birth and 18 years

older adult

person who is 65 years of age or older

Adult

person who ranges in age from 19-64 years old

age-related changes

physiological events due to increasing age, which affects drug responses

risk-to-benefit ratio

poor outcome (adverse effects of medications) in relation to good outcome (desired medication effects); increases with increasing age

What makes older adults more prone to adverse drug effects?

reduced number of receptor sites for medications

Body surface area

surface of a human body expressed in square meters

What is the most effective treatment of hypertension in older adults?

thiazide diurectics

What does a BLACK BOX WARNING mean?

this warning states that antidepressants may play a casual role in inducing suicidality in pediatric patients

What is total body water? How do children's differ from adults

total body water: The amount of water within the body (including intracellular and extracellular compartments, as well as water in the GI and urinary tracts) Total body water in adults: ~60% Total body water In newborns: ~80%

polypharmacy

use of several drugs during the same period