Lecture 12 - Pediatrics & Elderly Flashcards
(81 cards)
1
Q
List some special populations
A
- Infants and children
- Elderly people
- Pregnant & breastfeeding women
- Obese/underfed
- Patients with clinical issues:
- Liver failure
- Kidney failure and dialysis
- Extracorporate membrane oxygenation (ECMO)
- Therapeutic cooling
2
Q
Why are these populations special?
A
- Different PK/PD
- Use different drugs
- High potential of damaging self or other (pregnant/breastfeeding)
3
Q
Why teach us about special populations?
A
- Higher risks of adverse drug events
- Higher risk of ineffective therapy
- More complicated prescribing and dispensing
4
Q
Describe the paradox of modern drug development
A
1) Clinical trials provide evidence of efficacy and safety at usual doses in NORMAL populations
2) Physicians treat individual patients who can vary widely in their response to drug therapy (no response, efficacious and safe, adverse drug reaction)
5
Q
Drug prescriptions in pediatrics are often drugs used ____-______
A
off-label
6
Q
Why is pediatric prescribing much more complicated than prescribing for adults?
A
- the specific and general aspects of paediatric patients (size, immaturity)
- the limitations of commercially available dosage formulations
- the challenges of administering drugs
- the dearth of information about drug use in children
- the general inadequacy of clinical pharmacology training
7
Q
For the reasons we just discussed about pediatric prescribing being more complicated than adult, how should practitioners handle pediatric prescribing?
A
- prescribe judiciously
- select carefully the safest dosage regimen available
- educate their patients, caregivers and staff about their choices and expected positive and negative effects
- have available and use written, electronic, as well as human sources of expert advice
- document their therapeutic decisions and plans
- carefully monitor their patients’ responses to therapy
8
Q
Prescriptions may be off-label when given for a different: ??
A
- age group
- dosage
- indication
- dosage form
- route of administration
9
Q
___% of drugs prescribed in paediatrics are off-label
A
30-80
10
Q
List some novel drug devices for drug administration to children
A
- Modified teat/pacifier with drug-loaded reservoir
- Dosing spoon filled with liquid medicine
- Coated particles on dosage spoon (pulp-spoon)
- Dropper tube
- Dose-sipping technology (straw with medicine and beverage)
- Solid dosing pen
11
Q
List the divisions of childhood
A
- Infancy
- Toddler
- Pre-School
- School age
- Adolescent
- Early
- Middle
- Late
12
Q
____ ______ may increase with weight, height, age, BSA and CLcr (creatinine clearance)
A
drug clearance
13
Q
Ontogeny
A
the branch of biology that deals with the development of an individual organism or anatomical or behavioral feature from the earliest stage to maturity
14
Q
What is involved in pharmacokinetics?
A
Absorption
Distribution
Metabolism
Excretion
15
Q
Gastric pH is ____ in infants
A
lower
16
Q
Infants have an _____ absorption of drugs degraded by acid (ex. penicillin)
A
increased
17
Q
Biliary function is _____ in infants
A
reduced
18
Q
Infants have a _______ absorption of some drugs such as Pleconaril
A
decreased
19
Q
Infants have _____ gastric emptying which will cause an increased half-life of some drugs (ex. cisapride)
A
decreased
20
Q
Infants have altered GI tract absorption of some drugs: ______ very poorly absorbed by infants
A
Phenytoin
21
Q
Infants have ____ GI motility which can cause potentially greater absorption (ex. ahminoglycosides)
A
lower
22
Q
Infants have a marked _______ in gut wall activity of Phase 1 and Phase 2 enzymes
A
reduction
23
Q
Infants have ___ transporter function which can lead to reduced absorption
A
reduced
24
Q
What factors influence extra oral drug absorption?
A
- barrier thickness
- regional blood flow
- diffusional surface area
- hydration
25
Distribution of drug through VoD effected by ??
- Water-fat ratio
- Plasma protein binding
- Acid-base balance
- Regional blood flow
- Cardiac output
26
Do infants have more or less water than adults?
Infants have much more water (80%) than adults (60%)
27
Infants therefore have an ______ VD for water-soluble agents
increased
28
The BBB of infants is ___ functional
less
*this allows possibility for drug molecules that normally cannot access the brain to cross the BBB
29
Plasma protein binding is ____ efficient in infants
less
*this causes an increased clearance of highly bound drugs
30
Metabolic routes ____ at different rates
mature
31
____% of mothers initiate breastfeeding
80
32
___% of mothers take drugs
80
33
What is the MP ratio?
Milk-to-plasma ratio
34
pH of milk?
7.0
35
pH of maternal plasma?
7.4
36
Most drugs are safe if:
| ??
- They are commonly prescribed for infants
- They are considered safe in pregnancy
- They are not absorbed from the stomach or intestines
- They are not excreted into the milk
37
List some challenges of geriatric pharmacotherapy
- New drugs available each year
- HC approved and off-label indications are expanding
- Changing managed-care formularies
- Advanced understanding of drug-drug interactions
- Increasing popularity of nutraceuticals
- Multiple co-morbid states
- Poly pharmacy
- Medication compliance
- Effects of aging physiology of drug therapy
- Medication cost
38
Elderly:
| Rate of absorption may be ___
delayed
- lower peak concentration
- delayed time to peak concentration
39
Elderly:
| Overall amount absorbed (bioavailability) is _____
unchanged
40
Elderly:
For drugs with extensive first-pass metabolism, bioavailability may _____ because less drug is extracted by the liver:
-Decreased liver mass
-Decreased liver blood flow
increase
41
List some factors that affect absorption
- Route of administration
- What is taken with the drug
- Divalent cations (Ca, Mg, Fe)
- Food, enteral feedings
- Drugs that influence gastric pH
- Drugs that promote or delay GI motility
- Comorbid conditions
- Increased GI pH
- Decreased gastric emptying
- Dysphagia
42
Elderly:
| Have decreased body water which means decreased Vd for ______ drugs
hydrophilic
43
Elderly:
| Have decreased lead body mass so they have decreased Vd for drugs that bind to ____
muscle
44
Elderly:
| Increased fat stores which means _____ Vd for lipophilic drugs
increased
45
Elderly:
| Have _____ plasma protein (albumin) which means there is an increased percentage of unbound or free drug (active)
decreased
46
Elderly:
| Metabolic clearance of drugs by the liver may be reduced due to
- decreased hepatic blood flow
- decreased liver size and mass
Examples:
- morphine
- meperidine
- metoprolol
- propranolol
- verapamil
- amitryptyline
- nortriptyline
47
Phase 1 metabolism pathways
oxidation
hydroxylation
dealkylation
reduction
48
Phase 2 metabolism pathways
glucuronidation
conjugation
acetylation
49
Effect of phase 1 metabolic pathways
conversion to metabolites of lesser, equal or greater
50
Effect of phase 2 metabolic pathways
conversion to inactive metabolites
51
Medications undergoing Phase ___ hepatic metabolism are generally preferred in the elderly due to inactive metabolites (no accumulation)
2
52
Other factors affecting drug metabolism?
```
Gender
Comorbid conditions
Smoking
Diet
Drug interactions
Race
Frailty
```
53
List some effects of aging on the kidney
-decreased kidney size
-decreased renal blood flow
-decreased number of functional nephrons
-decreased tubular secretion
Results in: decreased glomerular filtrate rate (GFR)
54
Elderly:
| Aged kidneys results in decreased drug clearance of which drugs?
- atenolol
- gabapentin
- H2 blockers
- digoxin
- allopurinol
- quinolones
55
Elderly:
| _____ ______ is used to estimate glomerular rate
creatinine clearance (CrCl)
56
Elderly:
| Serum creatinine alone not accurate in the elderly due to ???
- lower lean body mass
- lower creatinine production
- lower glomerular filtration rate
57
Elderly:
| Serum creatinine stays in _____ range, masking change in creatinine clearance
normal
58
Measuring Creatinine clearance is ??
- time consuming
| - requires 24 hr urine collect
59
How do we estimate Creatinine clearance?
Cockroft Gault Equation:
(IBW in kg) x (140-age) / 72 x (Scr in mg/dL)
x 0.85 for females
60
Pharmacodynamics
the time course and intensity of pharmacologic effect of a drug
61
Age-related changes in pharmacodynamics:
| Increased sensitivity to sedation and psychomotor impairment with ________
benzodiazepines
62
Age-related changes in pharmacodynamics:
| Increased level and duration of pain relief with _____ _____
narcotic agents
63
Age-related changes in pharmacodynamics:
| Increased drowsiness and lateral sway with _____
alcohol
64
Age-related changes in pharmacodynamics:
| Decreased HR response to ____ ______
beta blockers
65
Age-related changes in pharmacodynamics:
| Increased sensitivity to _______ _____
anticholinergic agents
66
Age-related changes in pharmacodynamics:
| Increased cardiac sensitivity to _______
digoxin
67
PK and PD changes generally result in ______ clearance and ______ sensitive to medications in older adults
decreased clearance
| increased sensitivity
68
Elderly:
| How do we decrease the risk of drug intolerance and toxicity?
use of lower doses, longer intervals, slower titration
careful monitoring is necessary to ensure successful outcomes
69
What are some consequences of overprescribing?
- Adverse drug events
- Drug interactions
- Duplication of drug therapy
- Decreased quality of life
- Unnecessary cost
- Medication non-adherence
70
List some most common medications associated with ADEs in the elderly
- opioid analgesics
- NSAIDs
- anticholinergics
- benzodiazepines
- CV agents
- CNS agents
- musculoskeletal agents
71
Patient risk factors for ADEs
- polypharmacy
- multiple co-morbid conditions
- prior adverse drug event
- low body weight or body mass index
- age >85
- estimated CrCl < 50 mL/min
72
Most common DDIs?
- CV drugs
| - psychotropic drugs
73
Most common drug interaction effects?
- confusion
- cognitive impairment
- hypotension
- acute renal failure
74
Concepts in Drug-Drug Interactions?
- Absorption may be increased or decreased
- Drugs with similar effects can result additive effects
- Drugs with opposite effects can antagonize each other
- Drug metabolism may be inhibited or induced
75
_____ alters Vd of lipophilic drugs
obesity
76
______ alters Vd of hydrophilic drugs
ascites
77
____ may increase sensitivity, induce paradoxical reactions to drugs with CNS or anticholinergic activity
dementia
78
____ or _____ impairment may impair metabolism and excretions of drugs
renal or hepatic
79
drugs may exacerbate a _____ ______
medical condition
80
Principles of prescribing in the elderly
- avoid prescribing prior to diagnosis
- start with a low dose and titrate slowsly
- avoid starting 2 agents at the same time
- reach therapeutic dose before switching or adding agents
- consider non-pharmacologic agents
81
Elderly:
| Factors in non-adherence?
Financial, cognitive or functional status
Beliefs and understanding about disease and medications
