Drugs To Know

Question 1

Leucorvorin

Answer 1

Used to treat actuely low THF levels; often due to drug therapies
o Methotrexate – inhibits DHFR so folate can’t be turned into its active form (THF)
o Trimethoprim – antimicrobial that inhibits DHFR in bacteria and humans
o Pyrimethamine – antimalarial that inhibits DHFR in falciparum malaria and humans
o Phenytoin – antiepileptic that inhibits folate uptake
o Treat with leucorvorin (doesn’t need DHFR to be active)

Question 2

Folic Acid Supplementation

Answer 2

o Alcoholics/Liver disease – impairs absorption and diminishes folate storage proteins in liver
o Pregnant women – need more folate because they’re making a baby. Best to supplement to decrease incidence of neural tube defects
o Malabsorbtion - problems with absorbtion in the jejunum will impair folate the most
o Renal dialysis – removes folate from the blood

Question 3

Hydroxocobalamin

Answer 3

• Used to treat B12 deficiency

- longer lasting formulation

Question 4

Cyanocobalamine

Answer 4

• Used to treat B12 deficiency

Question 5

People who get B12 def.

Answer 5

o Pernicious anemia – autoantibodies for parietal cells (cause lack of intrinsic factor)
o Gastrectomy/Small bowel resection/Malabsorbtion/IBS affecting distal ileum/Gut bacterial overgrowth – this is where [IF- Vit. B12] receptors are located for absorption
o Chronic pancreatitis – lack of pancreatic enzymes stops release for [B12-haptocorin] for it to attach to intrinsic factor
o Thyroid disease – hypothyroidism causes increase of stomach pH (more basic), thus less release of Vit. B12 from R-binder
o Congenital IF deficiency – no IF means little absorption

Question 6

Ferrous Sulfate

Answer 6

• treatment of iron deficiency

- oral

Question 7

Ferrous gluconate

Answer 7

• treatment of iron deficiency

- oral

Question 8

Iron Dextran

Answer 8

• treatment of acute/severe iron deficiency
• parenteral

o Several concerns with this therapy:
• Anaphylaxis – full history/test dose should be given before starting therapy
• Iron overload – we’re bypassing normal regulatory processes for iron so ferritin/transferrin levels should be monitored to check iron stores/serum iron. If [serum iron>TIBC] then you’re in iron overload
• Adverse side effects – headache, light-headedness, fever, pain, flushing, utricaria, bronchospasm and many more

Question 9

Major complication of child eating too many iron pills

Answer 9

Necrotizing gastroenteritis

Question 10

whole bowel irrigation

Answer 10

• Used to flush any unabsorbed iron in acute iron overload

Question 11

deferoxamine

Answer 11

• IV iron chelator that will bind and get iron out of the blood
• Does NOT bind other trace metals
• After administered, [iron+deferoxamine] is excreted in bile/urine; urine is red
• May add to GI and heart problems present in iron toxicity, patient must be monitored to ensure this doesn’t happen

Question 12

activated charcoal

Answer 12

DON’T USE IT. It doesn’t work for acute iron overload

Question 13

intermittent phlebotomy

Answer 13

• Chronic iron overload
  o Patents with hemochromatosis or with multiple blood transfusions are the most common with chronic toxicity
  o Bad because iron will build up in the heart, liver, and other organs and kill them
  o If anemia is resolved, simply draining blood is the fastest way of lowering iron levels (one unit/week)