Chapter 3
***What are the drugs known to be teratogenic?
1. androgenic and estrogenic hormones 2. ACE inhibitors, ethanol, tetracycline 3. thalidomide, vitamin A, warfarin 4. angiotensin II receptor antagonists 5. anticonvulsants, antigenic agents, antithyroid 6. chemotherapy, statins, cocaine
When does full adult function occur?
9 to 12 months
What is polypharmacy?
use of multiple medications; multi drug therapy
---- levels give estimate of renal function.
Serum creatinine (BUN and GFR)
Describe the correlation between genetics and drug metabolism.
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
What is pharmacogenetics?
Study of how drug response may vary according to inherited differences
What is genetics?
Study of how living organisms inherit the traits of their ancestors, including function of metabolic pathways
How do you classify use in pregnancy categories?
1. A 2. B. 3. C 4. D 5. X
What two populations often lack a sufficient number of teeth for chewable medicines?
1. infants 2. older adults
What is absorption?
Process by which drugs are absorbed in the body; most common is via GI tract; other routes are parenteral and topical
Describe absorption in premature infants.
Slower gastric emptying time may allow increased absorption There stomachs aren't developed completely, more can be absorbed so this may cause toxicity
Describe X.
Studies are adequate, well-controlled, or observational; in animals or pregnant women have demonstrated positive evidence of fetal abnormalities. The use of the product is contraindicated in women who are or who may become pregnant DO NOT GIVE THIS MEDICATION
Describe D.
Studies are adequate, well-controlled, or observational; in pregnant women have demonstrated a risk to the fetus. However, the benefits of therapy may outweigh the potential risk
Describe excretion in preterm infants.
have 15% of the renal capacity of an adult
Describe excretion in neonates.
have 35% of the renal capacity of an adult
Newborns have an absence of enzymes needed for ----.
hydrolysis
Which stage is being described below? 1-24 months
infant, toddler
Which stage is being described below? 0-1 month
newborn, neonate
Which stage is being described below? 55-64 years
older adult
Which stage is being described below? 6-12 years
older child
Absorption by passive diffusion across the membranes and gastric emptying time depend on the ----.
pH of the environment
Which stage is being described below? <38 week gestation
premature
What is metabolism?
process whereby the body inactivates medications primarily occurs in the liver
Which stage is being described below? 75-84 years
the aged
Which stage is being described below? 85 years or older
the very old
Describe absorption in infants.
topical absorption increased
How is distribution influenced by gender?
total body fat higher in females
Describe distribution in geriatric patients.
total body water content decreases
What is distribution?
ways in which drugs are transported to site of action
Which stage is being described below? 3-5 years
young child
Describe the use of monitoring parameters for pregnant women.
- Avoid drugs if at all possible - When taking woman's history, be alert to possibility of pregnancy - Instruct patient to avoid drugs, alcohol, and tobacco - Try nonpharmacologictreatments before using medicines - Avoid herbal medicines
How should oral medications be given to toddlers?
- Allow the toddler to choose a position in which to take the medication - If necessary, disguise the taste of the medication with a small volume of flavored drink or small amounts of food; also, a rinse with a flavored drink or water will help to remove an unpleasant taste - Use simple commands in the toddler's jargon to obtain cooperation - Allow the toddler to choose which medication to take first if more than one is being taken - Provide with verbal and tactile responses to promote cooperation - Allow the toddler to become familiar with the oral dosing device
Which stage is being described below? 13-18 years
adolescent
Describe geriatric patients.
- Complete a thorough drug history, including prescription, OTC, herbal medications, and nutritional status - Evaluate vision and motor skills - When evaluating a new symptom, determine whether it was induced by a medication already prescribed - Start with smaller doses and gradually increase - Although people who are more than 65 years old represent about 14% of the US population, they consume more than 25% of all prescription medicines and 33% of all nonprescription medicines sold - Keep multidrug regimen simple - Review if any medications can be discontinued - Assess ability to pay for medications
Describe pediatric patients.
- Dosage adjustments expected during growth - Measure liquid medications using mL - Use appropriate dilution - Verify dosage prior to giving - Aspirin use linked with Reye's syndrome - Allergic reactions occur rapidly in children - Many medications are not approved by the FDA for us in children
How should oral medications be given to preschool children?
- If possible, place a tablet or capsule near the back of the tongue, and then provide water or a flavored liquid to help with the swallowing of the medication - If the child's teeth are loose, do not use chewable tablets - Use a straw to administer medications that could stain teeth - Use a follow-up rinse with a flavored drink to help minimize any unpleasant after taste - Allow the child to help make decisions about the dosage formulation, the place of administration, which medication to take first, and the type of flavored drink to use
How does gender affect drug therapy?
In almost every body system, men and women function differently; experience disease differently
Describe the use of monitoring parameters in regards to breastfeeding infants.
- Some drugs are known to enter breast milk and harm the nursing infant - For many drugs that are excreted in breast milk, no one knows with certainty what effect they will have on the infant - Discuss all medications with health care provider (including prescription, nonprescription, and herbal products) - Take medicine immediately after breastfeeding or just before infant's longest sleeping period
How should oral medications be given to infants?
- Use a calibrated proper or an oral syringe - Support the infant's head while holding the infant in the lap - Give small amounts of medicine to prevent choking - If desired, crush non-enteric-coated and slow-release tablets into a powder and then sprinkle the powder on small amounts of food - Provide physical comforting while administering medications to help calm the infant
Which is the safest pregnancy category?
A
Why does gender influence absorption?
A woman's stomach empties solids more slowly than a man's does -So medications stay in the gut a little bit longer Slower gastric emptying time may allow drug to stay in contact with absorptive tissue longer Body weight may aggravate the higher blood alcohol level and state of intoxication in women and men
What is carcinogenicity?
Ability of a drug to induce living cells to mutate and become cancerous When you hear the word carcinogen, you need to think cancer
Describe A.
Adequate, well-controlled studies in pregnant women have not shown an increased risk of fetal abnormalities
What are monitoring parameters?
All medicines have a number of parameters, expected therapeutic actions, common adverse effects, serious adverse effects, and any drug interactions Crucial that normal values for monitoring parameters and laboratory tests be related to the age of the patient being monitored
Describe B.
Animal studies have revealed no evidence of harm to the fetus; however, there are no adequate and well-controlled studies in pregnant women OR animal studies have shown an adverse effect, but adequate and well-controlled studies in pregnant women have failed to demonstrate a risk to the fetus
Describe C.
Animal studies have shown an adverse effect, and there are no adequate and well-controlled studies in pregnant women OR no animal studies have been conducted, and there are no adequate and well-controlled studies in pregnant women
Which type of topical drug is more readily absorbed by infants? a)Fat-soluble b)Water-soluble c)Emollient d)Protective
B Topical administration with percutaneous absorption is usually quite effective in infants because the outer layer of skin is not fully developed. Because the skin is more fully hydrated at this age, water-soluble drugs are absorbed more readily.
Which patient has the greatest percentage of body water? a)Older adult b)Middle-aged person c)Infant d)Toddler
C An infant has a total body water percentage of 74%, whereas a premature infant has an even higher percentage at 83%. As we age, our total percentage of body water decreases and our percentage of total body fat increases.
How does psychology affect drug therapy?
Attitudes and expectations play a major role in a patient's response to therapy; willingness to take medication as prescribed
Due to the decreased protein-binding capacity in preterm infants, what adjustment in dosage of protein-binding drugs would need to made? a)The dosage should be 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.
B Drugs that are relatively insoluble are transported in the bloodstream bound to plasma proteins (albumin and globulins). There is a decreased affinity for binding in infants, especially preterm infants. These drugs are then distributed over a wider area of the neonate's body. They will therefore require a higher dosage of these medications in order to achieve a therapeutic effect.
It is important to maintain therapeutic levels of drugs to avoid the complications of being over- or undermedicated. If a drug level of 0.5 to 2 ng/mL is considered therapeutic, a drug level of 0.45 ng/mL is considered to be what? a)Toxic b)Therapeutic c)Subtherapeutic d)Tolerant
C Drugs are therapeutic when maintained within the normal range for the drug. In this example, the level is below that indicated for the drug, or subtherapeutic. A subtherapeutic level would require increasing the dose for the patient to achieve the maximum benefit of the drug.
What is a genome?
Complete package of genetic coding of an organism
How does body weight affect drug therapy?
Considerably overweight patients may require an increase in drug dosage to attain the same therapeutic response
Which form of medication is more easily administered for a toddler who requires a course of antibiotics? a)Enteric b)Capsules c)Tablets d)Liquid
D Very small children are not able to swallow solids such as tablets or capsules. They should receive medications carefully measured in a calibrated dropper or oral syringe.
Describe excretion in geriatric patients.
Decreased renal blood flow Reduced cardiac output Loss of glomeruli Decreased tubular function
What are the factors that influence distribution?
Depends on pH, body water concentrations, fat tissues, protein binding, cardiac output, and blood flow
Describe the cumulative effect.
Drug accumulation occurs when the next dose is given before the previously given drug has been metabolized or excreted The previous drug has been metabolized or excreted out before the next dosage is given If someone has liver damage or kidney damage, this is when the cumulative effect builds up quickly May result in drug toxicity
What are teratogens?
Drugs that cause abnormal development of fetal tissues
Describe metabolism in infants.
Enzymes take several weeks to a year to develop
Describe pregnant patients.
Fetus is exposed to substances in mother's blood
What factors influence metabolism, overall?
Genetics, smoking, diet, other medications, liver disorders
Describe distribution in infants.
Higher total body water content, requiring higher dose on mg/kg basis Lower body fat Reduced protein binding in neonates
Describe absorption in geriatric patients.
IM absorption erratic -Because they start losing lean muscle mass and replaces it with fatty tissue Reduced salivary flow makes swallowing difficult -If a patient is having a hard time swallowing, crush it and mix it with a small amount of food and serve it with a full glass of water Transdermal absorption hard to predict Timed-release/enteric-coated tablets cannot be crushed Reduced GI acidity affects absorption Slower gastric emptying time Decreased GI motility and blood flow
Describe absorption in neonates.
IM absorption erratic, reduced gastric acidity There is no muscle tone yet that is why IM absorption is erratic
What are some potentially inappropriate medications for geriatric patients?
Includes medications that should be avoided and those that are rarely appropriate: Some barbiturates, benzodiazepines, and some narcotics Some are considered appropriate to give only with certain indications but may have potentially adverse reactions Use these medications with older adults only as a last resort
How does age affect drug therapy?
Infants and the very old tend to be most sensitive to drug effects Aging process brings about changes in body composition and organ function
---- refers to speed at which the intestine moves foods, secretions, and other ingested matter along, and this rate varies with age.
Intestinal transit
Describe metabolism in older adults.
Liver cells decrease, blood flow decreases
Describe 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
Are drug tolerance and drug addiction the same thing?
NO
Describe drug tolerance.
Occurs when a person begins to require a higher dosage of a medication to produce the same effects that a lower dosage once provided -You need higher dosages to get the same effect -When the doses are higher, side effects are also going to increase Can be caused by psychological dependence -Can be both physical and psychological -We try to get our patient's to take the lowest dose that will give a therapeutic response
How does illness affect drug therapy?
Pathologic conditions may alter rate of absorption, distribution, metabolism, and excretion of drug Patients with kidney failure generally will excrete drugs at a slower rate
Describe the nocebo effect.
Patient's negative expectations can result in a less-than-optimal outcome Patient is not expecting a good outcome therefore the outcome is negative
Describe the placebo effect.
Patient's positive expectation can positively affect the outcome Placebo is the most effective drug out there
How does metabolic rate affect drug therapy?
Patients with higher-than-average metabolic rate tend to metabolize drugs more rapidly Chronic smoking enhances metabolism of some drugs
Describe physiologic drug dependence.
Person develops withdrawal symptoms if drug is withdrawn
Describe psychological drug dependence.
Person is emotionally attached to a drug Harder to treat because we can get your body weened off of it but its hard to get a patients mind weened off of a drug
Describe drug dependence.
Person is unable to control his/her ingestion of drugs Not that the person needs it but they may have adverse effects or side effects if the medication is not given Sometimes a person is weened off the drug or we give other medications to counteract this drug
What is another word for drug dependence?
addiction or habituation
Which stage is being described below? 19-54 years
adult
How are most pediatric dosages calculated?
by milligrams per kilogram of body weight (mg/kg) to adjust for growth rate
What is excretion?
drug metabolites and the drug itself are excreted from the body
Which stage is being described below? 65-74 years
elderly