Prescribing in the elderly

Question 1

Age related changes

Answer 1

Adults 60-80 years
* Lower percent body weight as water - less fluid reserve
* >20% reduction in lean muscle mass - even with exercise
*35-45% body weight as fat in women - lipophilic drugs will be absorbed/storred in fat, extending half life (benzos, sedatives)
* 36-38% boday weight as fat in men
* lowe serum albumin - meds that bind will albumin will ned a lower dose - coumadin/warfarin
* 20% loss of kidney mass - suseptable to nephrotoxins
* 50% reduction in heapatic blood flow - decreased liver metabolism

Question 2

Highly protien bound medications

Answer 2

• the lower the albumin the higer the amount of free drug available, increasing the therapudic effect/toxicities
• warfarin
• phentoin (Dilantin)
• Valproic acid (Depakote)
• Diazepam (Vallium

Question 3

Systemic Anticholinergic effects in elderly

Answer 3

• Dry mouth
• Blurred vision
• Urinary retention (BPH)
• Sedation
• Agitation
• Tachycardia
• Hyperpnea
• Mydrasis
• Flushing
• Psychosis
• Seizure
• Coma
• Hyperthermia

OR
* dry as a bone
* red as a beet
* mad as a hatter
* hot as a hare
* can’t see
* can’t pee
* can’t spit
* can’t shit

ex: diphenhydramine

Question 4

Commonly used meds used in elderly with systemic anticholinergic effect

Answer 4

meds to treat over active bladder
* oxybutinin - sustained release beeter in elderly
* oxytrol (OTC for women)

antidepressants
* tricyclic antidepressants - avoid amytriptaline, tradazone least anticholinergic
* some SSRIs - avoid Paroxetine, less sedation with sertraline, citalopram or escitalopram (preferred due to lest drug interactions)

Question 5

QT prolongation

Answer 5

• any drug that prolongs QT will increase risk of torsades de pointes
• the risk of torsades with erythromycin or clarithromycin is greater in females
• Cilaopram (celexa) - dose >40 mg not recomended for all.

Question 6

Citalopram and QT prolongation

Answer 6

not reccomended with
* congenital long QT, bradycardia,hypokalemia, or hypomagnesemia, recent acute MI, or uncompensated HF
* in pts taking other drugs that prolong QT interval

Do not exceed 20mg/day
* age >60, hepatic impairment, taking tagament, or PPI

In pt with persistent QT measurements exceeding 500ms, discontinue citalopram

Escitalopram is better choice, no drug interactions, or QT prolongation

Question 7

In elderly choose drugs with shortes half-life and least drug interactions

Answer 7

shortes to longest half life
1. Paroxitine - most anticholenrgic
2. sertraline
3. escitalopram - best option
4. citalopram
5. fluoxetine - very long half life

Question 8

Sliding scale insulin per Beers criteria

Answer 8

• avoid due to hier risk of hypoglycemia without improvement in hyperglycemia
• refers to the sole use of short/rapid acting insulins to manage or avoid hyperglycemia in absence og basal/long acting insulin

Question 9

Sliding scale correction

Answer 9

theuse of additional short/rapid acting insulin in conjunction with scheduled insulin
* about 1 unit of rapid acting insulin will lower BS by 50mg/dl

if goal BS < 150
* BS200 -249: give 2 units
* BS 250-300: give 3 units
* BS 300-349: give 4 units
* BS >350: give 5 units

if GFR is <45 cut dose in half

in frail elderly with limited life expectancy A1C goal <8

Question 10

Pharmacodynamics of ederly will decrease drug effect of some drugs

Answer 10

age-related changes in vascular, pulmonary, cardiac tissues - loss of beta receptors
* decreased effect of beta agonists - albuterol, salmeterol
* decreased effect of beta antagonists - metoprolol, carvedilol
* instead use inhaled muscarinic antagonist - tiotropium
* instead use CCB - amlidipine (increased sensitivity to diltiazem)

Question 11

Statin use in elderly

Answer 11

• no evidednce for initiating statin in >76 years for prevention
• may be continued with established ASCVD
• may consider in these at high risk such as those with DM, CKD not on dialysis,

Question 12

PPI use in elderly

Answer 12

consequences of long term use:

rebound hypersecretion if using for >2 months
* consider tapering to every other day, histamine blocker (rantidine or fomotidine) and PRN antacid

Potential decrease in absorbtion of select micronutrients requireing an acididc environment for absorbtion
* iron, B12

Increased fracture risk likely due to decreased Ca absorption (calcium citrate less affected can use as a supplement)
* 25% increase in overall fractures
* 47% increase in spinal fractures in post menopausal women

Magnesium absorption impaired
* increased risk of hypomagnesemia when othe mg depletinig meds are used (thiazide, loop diuretics)
* digoxin toxicity risk increased with low mg

Question 13

PPI per Beers criteria

Answer 13

avoid scheduled use for >8 wks unless for high risk pts
(oral corticosteroids or chronic NSAID use), erosive esophagitis, barrett’s esophagitis, pathological hypersecratory condition, or demonstrated need for maintainance therapy.

*all are CPY450 2C19 inhibitors
* meds end in “-prazole”

Question 14

Drug induced Hyperkalemia

Answer 14

TMP-SMX - induced hyperkalemia
* structurally similar to K-sparing diuretic, inhibiting K secreation, prinicple site of action is distal tubule
* EKG show tall tented T waves
* avoid use if pt is taking spironoloactone, ACEI, ARB

Question 15

ACEI use in elderly

Answer 15

• if mild renal impairment - assure adequate hydration, take ACEI once daily in morning allows for overnight excretion of renal potassium to avoid hyperkalemia

Question 16

Medications for Alheimer-type dementia in older adults

Answer 16

• cholinesterase inhibitors (Aricept) are associated with increased rates of syncope, bradycardia, pacemaker insertion, and hip fracture