Pharm - vitamin deficiencies Flashcards
What population is more susceptible to vitamin deficiencies
elderly
What are the most common nutritional deficiencies
Vit D and Vit B6
What are the classifications of vit D deficiency
<20 - insufficiency
<12 - deficiency
Goal - 30+
>100 - toxicity (may be hypercalcemia
What are some causes of vit D deficiency
Reduced sun exposure
-homebound
-darker skin
-elderly
Malabsorption
-gastric bypass
-crohn’s disease
What drug interactions can cause vit D deficiency?
carbamazepine
corticosteroids
orlistat
What is vit D necessary for
calcium absorption
bone formation
What are the benefits of vit D replacement
reduce bone loss and fracture
How is vit D stored in the body?
25-OH-vitD gets turned to 1,25 dihydroxy Vit D by kidneys
Screening for 25(OH)vit D should be reserved for
patients with osteoporosis or risk factors (high cost)
How long after starting Vit D supplements should levels be rechecked
wait at least 12 weeks
How should vit D be prescribed (levels)
high doses initially
then titrate to lower doses as maintenance
What is vit D3 naturally made in the body called
cholecalciferol
What type of vit D is available OTC
cholecalciferol
What is vit D2 made synthetically called
ergocalciferol
What type of vit D is available in prescription form
ergocalciferol
What is prescription strength for vit D
50,000 unit capsules
What is the repletion dosing for vit D is levels are <12
D2 or D3 50,000 weekly
What is the repletion dosing for vit D is levels are 12-20
D2 or D3 800-2000 daily
What is the repletion dosing for vit D is levels are 20-29
OTC daily dose 600-2000 D3
What is the maintenance dose of vit D
600-800 daily
Safe upper limit is 4000 daily
What population usually has vit B12 deficiency
older adults >65, usually asymptomatic
What are the possible complications of B12 deficiency
Macrocytic anemia
neuro complications
-parasthesias
-psychotic symptoms
What is required to absorb B12
stomach acid and pepsin
pancreatic protease
intact upper GI system
What are the causes of vit B12 deficiency
pernicious anemia
malabsorption
-meds (PPI, H2, metformin)
H. pylori
Surgery (gastric bypass)
old age due to decreased stomach acid production
What dietary options have B12
meat
dairy
*problem for vegans
Causes of high B12
not toxic; concern about malignancy, renal disease, liver disease
What is the normal B12 level
> 300
What is the borderline low and low B12 level?
200-300 borderline
<200 low
What can help diagnose B12 deficiency
MCV >100 fl (macrocytic anemia)
MMA and homocysteine
Why is early B12 treatment important
neurologic manifestations may be irreversible with prolonged deficiency
What should be the priority to treat B12 deficiency
correct underlying cause
What route should be used for B12 is neuro complications?
Use IM first
What is the parenteral therapy for Vit B12?
Cyanocobalamin
-IM or SubQ
-oral
What do most multivitamins contain?
50-150% of the recommended dietary allowance for all vitamins
Is there a major benefit to taking multivitamins
benefits and risks are conflicting
What is enteral nutrition?
tube feeding - uses GI tractWha
What are the benefits of enteral nutrition?
favored over parenteral nutrition
-fewer infectious complications
-earlier gut function
What are the types of enteral nutrition
NG tube
OG tube
ostomy options
Can you administer medications enterally
it is off-label because it is not clear how medication will perform after bypassing GI tract
What medications should never be administered through EET?
sustained release (SR, XR)
modified release (MR)
enteric coated (EC)
What types are meds are typically okay to administer through EET
those that are acceptable to crush
-immediate release solid dosage forms
liquid
open capsules
dilute medications - need to use sterile water
What are some things to remember when giving meds enterally
flush tube between drug administrations
administer drugs separately
Always refer to “do not crush” list at facility
Can the same parenteral line be used for nutrition and drug administration?
No; need to have a dedicated IV line for parenteral nutrition
What meds are acceptable to add to parenteral nutrition solutions?
regular insulin
famotidine (plus of -tidines)
heparin
Never add meds to parenteral nutrition solutions after it?
leaves the pharmacy
What is TPN?
total parenteral nutrition
What is PPN?
Peripheral parenteral nutrition
What are the 2 types of TPN?
central
-allows for greater osmolarity
peripheral
-osmolarity must be <=900 to decrease risk of phlebitis
When is TPN used?
hospital
long term care
unable to eat or absorb nutrients through GI tract
-major surgery
-severe burns
-head trauma
-sepsis
Indications for parenteral nutrition?
GI tract is not functional
disease requiring complete bowel rest
How are TPN solution infused (time)
over hourly rate, either 24 hours or 12 hours
What are the components of TPN?
protein as amino acids
carbs as glucose
fat as lipid emulsion
other dietary components (like electrolytes)
How are TPN components ordered?
separately
What is the first step in calculating TPN?
calculate total kcal needed for 24 hours
-typically 15-30 kcal/kg
-burn patients require more
What is step #2 in TPN calc
determine protein requirements
-consider renal issues (less protein)
What is step #3 in TPN calc
determine grams of amino acids necessary to meet protein requirements
What is step #4 in TPN calc
multiply the grams of protein by 4 kcal per gram to determine number of kcal provided by protein
What is step #5 in TPN calc
subtract protein kcal from total kcal required
What is step #6 TPN calc
determine kcal to be provided by lipids
-60% of nonprotein kcal
What are the different lipid values to be calculated for step 6
20% lipids will supply 2kcal per mL
10% lipids will supply 1.1 kcal per mL
In what cases do lipids need to be omitted from TPN calc
contraindications like hyperlipidemia or egg allergy
What is step #7 TPN calc
subtract lipid kcal from non-protein kcal
-give remaining kcal given as dextrose
-divide kcal needed by 3.4 to calculate grams of dextrose
What is step #8 TPN calc
solutions with osmolarity >900 require central venous access
How many kcal per gram for protein
4
How many kcal per mL with 10% lipids
1.1
How many kcal per mL with 20% lipids
2
How many kcal per gram with dextrose
3.4
What is one thing to watch for with TPN solutions
watch calcium and phosphorus concentrations - if mixed in too high concentration an insoluble precipitate of calcium phosphate may develop which increases mortality risk
-filters do not remove this precipitate
How is potassium excreted
90% by kidneys
10% in feces
What are the significant potassium levels
normal 3.5-5
severe <2.5
What are the symptoms of severe hypokalemia
ECG changes
arrhythmias
cramping
muscle impairment
What is the most common drug induced cause of hypokalemia
potassium wasting diuretics (loop diuretics)
What increases entry of potassium into cells
insulin
caffeine
What increases urinary losses of potassium
furosemide
What increases GI elimination of potassium
laxatives
What is the goal of hypokalemia treatment
prevent life threatening complications
replace potassium deficit
reverse underlying cause
What is something else that should always be corrected along with potassium
low magnesium - may contribute to potassium wasting
How should you decide which route to manage hypokalemia?
outpatient - oral
inpatient - IV
What levels indicate need to potassium repletion
<3.0
<3.5 + underlying cardiac conditions predisposing an arrhythmia
Which route of potassium chloride has the highest incidence of GI adverse effects and esophageal irritation?
Liquid
What is an option for hypokalemia treatment besides potassium chloride?
potassium sparing diuretics like aldosterone antagonists
-spironolactone
-eplerenone
In what cases are aldosterone antagonists used?
HF and resistant HTN
What are the AA side effects that are worse with spironolactone
gynecomastia
hyperkalemia
impotence
What to note about potassium sparing diuretics
they are on the Beers list - increased risk in elderly for chronic kidney disease with triamterene
What symptoms indicate severe hypokalemia that should be treated IV
arrhythmia
muscle weakness
rhabdomyolysis
What to note about IV potassium chloride?
highly irritating to peripheral veins with rate >20/hour
need to use central vein or multiple peripheral veins if high rates are being given
What are potassium chloride mini mags
100-200 mL of sterile water + 10mEq of potassium
-for peripheral vein administration
*if 40mEq instead of 10, need central vein administration
What should be done if patient is experiencing pain during IV administration of potassium chloride?
reduce potassium concentration
reduce infusion rate (preferred)
What are the monitoring signs and symptoms of severe hypokalemia
ECG abnormalities
muscle weakness
paralysis
At what rate is rebound hyperkalemia a concern
> 10
What should be done with potassium chloride IV administration when hypokalemia is no longer severe?
switch to oral therapy
