7 - Geriatric & Pediatric Flashcards
Define elderly
Those aged 65 years or more
What are the effects of aging on drug absorption?
- Decrease in gastric secretion elevates pH in GI tract
- May result in some dissolution of enteric-coated formulations in stomach and cause GI irritation, incomplete absorption of acidic compounds from stomach, or decreased rate of absorption of poorly soluble weak bases
- IM absorption affected from loss of muscle
What are the effects of aging on drug distribution?
- Loss of muscle mass and increase in adipose mass
- Increase in Vd for lipid-soluble drugs and decrease for water soluble drugs (increased Vd prolongs half life; reduced Vd for water-soluble drugs balanced by reduction in renal clearance has little net effect on t1/2)
- Decrease in albumin levels
- Amount of unbound drug may increase for drugs that are highly protein bound (clinical significance unclear)
What are the effects of aging on drug metabolism?
- Decreased liver volume and hepatic blood flow => decreased first-pass metabolism
- Decreased rate of metabolism for some drugs
- Decline in phase 1 oxidative reactions; phase 2 conjugative processes appear consistent
- Reduction in renal function (may affect drug metabolism in liver)
What are the effects of aging on drug excretion?
- Decline in renal blood flow
- Slowing of glomerular filtration rate (GFR)
What does it mean when GFR slows?
- Drugs excreted primarily by kidney may require dosage adjustment
- Creatinine clearance often used to calculate these adjustments
- Affects clearance of many water-soluble drugs
What does arthritis cause?
Deterioration of cartilage components of hands, hips, knees, and spine
What are options to help px w/ swallowing issues?
- Artificial saliva
- Dosage forms like quick-dissolve films or ora-dispersible tablets
- Formulation into suspensions or other liquids
- Crushed tablets or capsule contents mixed w/ food (like pudding) just prior to administration
Which route is most desirable for elderly?
Oral
Which oral dosage forms AREN’T recommended for elderly and why?
- Chewable tablets – decrease in chewing ability
- Capsules – potential for mucosal adherence
- Sublingual and buccal tablets – reduced bioavailability for px w/ dry mouth
What are some alternatives to solid oral dose forms?
- Granules
- Effervescent tablets
- Dispersion or soluble tablets
- Concentrated oral solutions
What are advantages for granules?
- Circumvent difficulty in swallowing and provide some rehydration
- Not affected by changes in gastric-emptying rate
- Solid, so stable
What is an advantage to effervescent tablets?
Provide an easy-to-swallow form which also rehydrates px
How does the skin change w/ aging?
Decreased transdermal absorption of medications
What are the major concerns w/ adherence in elderly?
- Take multiple medications
- Various physical impairments
What are some approaches to improve adherence in elderly?
- Taste preference
- Package and label design
- Compliance aids
Define the different stages of childhood
- Pediatric = 0-18 years
- Premature = under 37 week gestational age
- Neonate = 1 day to 1 month
- Infant = 1 month to 1 year
- Child = 1-12 years
- Adolescent = 12-18 years
How are the most accurate pediatric doses determined?
Using weight and age
How does drug absorption differ in pediatrics?
- Gastric acid output approaches adult levels by 3 months
- Achlorhydria present for first 2 weeks
- Gastric-emptying and intestinal transit time erratic in neonates, but generally protracted so absorption delayed
- Pancreatic enzyme activity and concentration of bile salts low so lipid-soluble drugs poorly absorbed in early infancy
- Colonization and metabolic activity of GI bacterial flora don’t approach adult values until 2-4 y/o
Only ____ release products should be used in pediatrics
Immediate
How does absorption of topical medication differ for infants and children?
- Have 3x the skin surface area of adults relative to weight
- Skin is thinner and more hydrated so prone to increased absorption and systemic exposure
Do infants have a higher or lower ratio of body water to body fat than adults? What does this cause?
- Higher
- Causes higher Vd for hydrophilic drugs and lower Vd for lipophilic drugs
- Means that hydrophilic drugs require higher per weight dose for neonates
Do neonates have a more or less permeable BBB than adults? What does this mean for narcotic analgesics?
- More permeable
- Increased response to narcotic analgesics
Do children under 6 m/o have higher or lower albumin levels than adults? What does this mean for highly protein bound drugs?
- Lower albumin levels
- Have higher than expected unbound fractions of drugs that are highly protein bound
