Week 5: Antiplatelets, Iron, Folic Acid, and Vitamin B12

Question 1

Aspirin MOA & indication

Answer 1

• antagonizes cyclooxygenase pathway (COX-1) thus interfering with platelet aggregation
• salicylated NSAIDs
• inhibits prostaglandins
  ind: MI, stroke prevention, acute coronary syndrome

Question 2

Aspirin ADRs

Answer 2

• GI ulcer
• angioedema
• Steven Johnson syndrome

cross sensitivies with: NSAIDS, Reye syndrome in kids

Question 3

Aspirin cautions/contraindications

Answer 3

• NO in pediatrics w/ influenza or chickenpox
• NO in CC < 10 and severe liver disease
• low dose used to prevent preeclampsia in pregnancy; low dose in lactation
• is affected by herbals (garlic, gingko, ginseng) & NSAIDS

Question 4

Clopidogrel (Plavix) MOA & indication

Answer 4

• reduces platelet aggregation by inhibiting adenosine diphosphate pathway (ADP) (no effect on prostaglandins = not an inflammatory)
• blocks the ADP receptor so that platelets cannot adhere to one another at that receptor
  ind: unstable angina, recent MI, ACS

Question 5

Plavix Pharmacokinectics

Answer 5

• Prodrug
• metabolized by CYP2C19
• Excreted in urine and feces

Question 6

Clopidogrel (Plavix) Cautions/precautions

Answer 6

• avoid in pts with GI ulcers (anti-prostaglandin- prostaglandins are GI protective)
• severe hepatic dysfuction - unable to metabolize into active form
• use with PPIs can attenuate (weaken) the antiplatelet effect of Plavix

NO NSAIDS

Question 7

Clopidogrel (Plavix) ADRs

Answer 7

• bleeding
• Steven Johnson syndrome (rare)

Question 8

What is the most common iron preparation given because it contains the highest amount of elemental iron?

Answer 8

Ferrous sulfate (20% elemental iron) - 65mg of elemental iron in a 325mg tablet - dosing is based on the amount of elemental iron

Question 9

Iron preparations pharmacokinetics

Answer 9

• take on an empty stomach
• take with vitamin C to help with absorption
• avoid taking with dairy products, eggs, antacids, calcium which may inhibit absorption

Question 10

Iron preparations ADRs

Answer 10

• GI symptoms - constipation, GI upset
• acute iron toxicity with overdose
• keep away from children

Question 11

Iron preparations - monitoring

Answer 11

• check reticulocyte count (immature RBCs) 7 to 10 days after starting iron therapy - if this is not back to normal, there is something else wrong
• check and Hgb and Hct at 2-4 weeks then Hgb, Hct , and ferritin at 3 months

takes 6-12 months to replenish

Question 12

Folic acid deficiency - causes

Answer 12

• poor dietary intake/absorption
• pregnancy, alcoholism, hypothyroidism, megaloblastic anemia
• increased demand
• impaired utilization

Question 13

Folic acid supplementation indications

Answer 13

• treatment of megaloblastic anemia
• prevention of folic acid deficiency
• increased demand during pregnancy, ETOH abuse, hypothyroidism, hemolytic anemia, or malignancy

Question 14

Vitamin B12 deficiency causes/indications

Answer 14

• decreased absorption due to lack on intrinsic factor (made from parietal cells in the stomach), without intrinsic factor, Vb12 can’t be absorbed and leaves body as waste
• can be caused by GI surgery (gastric bypass), diseases of the ilium, constipation
• pernicious anemia d/t malabsorption issues (need injections for life)
• Vitamin B12 is needed for the final steps of folate metabolism

Question 15

Vitamin B12 ADRs

Answer 15

hypokalemia (monitor k!!!)

headache

pain @ injection site

transient diarrhea

urticaria

pruritis