April 8th Flashcards
what might happen to lithium levels if an elderly individual is on a low sodium diet
higher blood lithium levels
what might happen to an elderly individual if they’re on cyclosporine and consuming a low sodium diet?
potential for nephrotoxicity
what’s special about grapefruit?
increases absorption of certain medications (antiacids, statin-type drugs). therefore grapefruit juice is prohibited with these kinds of drugs as to avoid liver toxicity
why do the elderly in particuar need to be careful with their diet?
they often take multiple medications which have additive/conflicting effects
what is polypharmacy?
having adverse reactions to taking multiple medications
what is glomerulonephritis?
when there is type 3 hypersensitivity in which immune factors (immunoglobulin G and complement), where drug metabolites are not properly excreted, then there are immune complexes that bind to these metabolites and cause an inflammatory response that causes kidney damage
describe what happens to kidney mass with aging?
30% decrease in renal mass by age 90
what’s the problem with vitamin D when you’re old?
smaller kidney –>the metabolically active form of vit D requires the 1-alpha hydroxylase enzyme that bioactivates vit D into the 1,25-dihydroxy vit D.
this ability to bioactivate goes down, so even if they’re consuming enough vit D, they can still experience a deficiency
what’s special about dehydration with elderly?
increased risk, especially with muse of diuretics and laxatives
in what ways can drugs block actions of vitamins?
- inhibit absorption
- bind them
- enhance their catabolism
- enhance their excretion
- inhibiting their activation
effect of cholestryamine
meant to lower cholesterol (bile acid sequestrants) but can decrease fat soluble vitamin absorption
effect of antibiotics
affects GI and bioavailability of nutrients by inhibiting action of enzymes on epithelium, can damage mucosa’s villi and microvilli
–> nutrient deficiencies when used long-term
effect of anti-inflammatory drugs
- inhibits lactase
- damage gut itself to decrease absorption of fats and micronutrients
effect of laxatives
- loss of fat-soluble vitamins
- faster transit time means less absorption esp for Ca and K
effect of anti-ulcer drugs
- less HCL production
- decreased B12 released from food
- less B12 available for binding with intrinsic factor for absorption
effect of loop diuretics (furosemide)
- increased excretion of thiamin
- cardiac abnormalities
effect of non loop diuretics
- potassium depletion
- risk of cardiac arrhythmias
effect of asprin
increases folate excretion by binding to plasma albumin involved with transport of vitamin to tissues. leads to increased urinary excretion of the now free folate in the blood.
what is diarrhea?
3 or more unformed bowel actions in 24 hours
acute diarrhea lasts for how long?
less than 2 weeks
chronic diarrhea lasts for how long?
3-6 weeks
why are the elderly more susceptible to diarrhea?
diminished immune response and they tend to have more systemic bowel diseases (IBS, colitis) and others like pneumonia, hypothyroidism
list drugs commonly associated with diarrhea
- antibiotics (most common)
- osmotic agents (laxatives, antacids)
- antimetabolites
how do antimetabolites cause diarrhea?
direct damage to epithelial cells
mechanism of grapefruit juice?
the juice inhibits cytochrome p450 enzyme which is involved in the inhibition of the metabolism of the drugs (inhibition of inhibition –> enabling); this is present on the level of the intestines where absorption of the drug will be increased
what is bone remodeling
replacement of old bone with newly synthesized bone
what kind of cells synthesizes the bone matrix?
osteoblasts
what kind of cells break down the old bone mineral
osteoclasts
what removes the proteins in bones?
phagocytes
why are osteoblasts important?
adapts bone to various mechanical needs, repairing microdamages or old bones; allows secretion of calcium stores to maintain homeostatic blood levels
what happens to the capacity for bone remodeling with age?
decreases –> secondary to decline in muscle mass
why is osteoporosis more common in elderly?
- decrease of estrogen/androgens in both males and females
- increased oxidative stress
- less activity of osteoblasts
- excessive inflammation that causes bone resorption
at what ages do older ppl have accelerated rates of bone loss?
women: after 55
men: after 65
define osteoporosis
having a bone density <2.5 SD below mean for young ppl
what is osteopenia?
bone density with SD < 1 to 2.5 of the mean for young ppl
what is type 1 osteoporosis?
postmenopausal osteoporosis (ages 50-70); due to drop in estrogen levels leading to rapid bone loss
role of estrogen and bones?
inhibits the activity of osteoclasts
what is type II osteoporosis?
senile osteoporosis; involves both cortical and trabecular bone loss; associated with underactivity of osteoblasts due to accumulation of fat in bone marrow –> inadequate bone formation relative to bone resorption
how much accretion of bone after age of 30?
1% per year til menopause
how much accretion of bone after menopause?
3-5% for 6 to 8 years after which accretion is more gradual
when is peak bone mass?
age 30
how much bone mass can a post-menopausal woman lose?
up to 20%
factors increasing likelihood of the development of osteoporisis
- sex (men have greater bone mass)
- being small
- age/menopause
- family history
- irregular menstruation
- anorexia nervosa
- low Ca diet
- medication (corticosteroids, anticonvulsants)
- inactive lifestyle (esp lack of weight-bearing exercise)
- cigarette smoking
- excessive alcohol consumption
- being Caucasian or asian
role of vit D in prevention/treatment of osteoporosis?
decreases risk of bone resorption, enhances calcium absorption, enhances mineralization of bone matrix
why is vit D levels lower in older folks?
- drop in renal mass and decreased capacity to metabolically activate cholecalciferol or 1,25 dihydroxy vitamin D
- decrease in ability to synth from sunlight decreased amounts of 70-dehydrocholesterol (precursor to cholecalciferol) in skin and less time spent outdoors
how to counteract drop in vit D seen in old ppl?
give calcitriol
what happens if blood concentration of vit D goes too high?
risk of hypercalcemia and hypercalcuria
why is vit D absorption lower for postmenopausal women and elderly?
- diminishment of ability to synth metabolically form of vit D
risk factors for bone loss
- low calcium intake
- excessive phosphorous intake
- high animal protein diet
- vit D deficiency
- low PA
- excessive alcohol
- excessive caffeine intake
- smoking
how to counteract bone loss?
- weight baring exercise
- walking
stimulates osteogenesis (stimulation of osteoblasts)
recommendations for preventing bone loss?
- PA: aerobic activity for 20 mins, 3 times a week AND weight training
why is weight training important?
stimulates and enhances bone health
- having sufficient muscle strength and coordination for daily activities
- decreases risk of fall-related fractures
- enabling sufficient muscle to prevent chronic
why is osteoporosis associated with chronic pain?
compression of the ribs and bones on nerve cells
how to prevent osteoporosis?
- maximize bone mass in premenopause
- screening
- control of bone mineral loss during postmenopause
- calcium (1.2g) and vitamin D (800 IU) supplements
- hormone replacement therapy (HRT)
why is HRT controversial?
- associated with adverse health risks when given for a prolonged period
- seems to be fine short-term
