Drugs to treat anemia Flashcards
Main goal of therapy of Iron Deficiency Anemia
Main goal of therapy is to identify and treat the underlying cause
some causes of Iron Deficiency Anemia
o Blood loss from tumor, varicosity, or other bleeding lesion
o Iron malabsorption
patient presentation with Iron Deficiency Anemia
o Weakness
o Headache
o Irritability
o Varying fatigue and exercise intolerance
o Pica [especially ice craving (pagophagia), but can be other things]
o Restless leg syndrome
Iron Deficiency Anemia General Treatment Issues
- “Secondary” treatment is via iron supplementation
- Choice of preparation is based on acuity of illness as well as the ability of the patient to tolerate PO formulations
- PO is first-line in most patients
PO Iron: Products
Most appropriate (equally effective) contains ferrous salt such as:
o Ferrous sulfate: 65 mg elemental iron/tablet
o Ferrous fumarate: 106 mg elemental iron/tablet
o Ferrous gluconate: 28-36 mg/ iron/tablet
Dose is 150-200 mg/d of elemental iron
o Ex: single 325 mg ferrous sulfate tablet taken PO tid provides 195 mg of elemental iron per day
PO Iron: Treatment Issues
o GI ADRs decrease adherence
o Malabsorptive states (e.g., celiac disease, Whipple’s disease, bacterial overgrowth syndromes)
o PO iron may take 2 months to improve anemia and 6-8 months to restore iron stores
o IBD patients may have worsening of disease
o Heavy blood loss may not be corrected by PO iron supplements
o Dialysis patients do not respond enough to PO iron
o CKD patients may not absorb PO iron (impaired iron transport, concomitant use of Ca-containing salts, H2 blockers, phosphate binders, general malabsorption)
PO iron Frequent GI ADRs
metallic taste, constipation, diarrhea, and thick/green/foul-smelling stool
GI-related ADRs seem to be directly related to the amount of______
elemental iron
Should PO iron be dosed on empty stomach?
yes
what medium is Po iron best absorbed?
acidic medium
how is PO iron dosed with antacids/calcium
- Dosed 2 hours before or 4 hours after antacids/calcium
PO Iron: DDIs
- H2 Blockers, PPIs, antacids decrease absorption
- Tetracyclines & Quinolones decrease absorption
- Ca salts: decrease absorption
- Vitamin C: increase absorption
- decrease absorption of thyroid hormones- Avoid dosing at same time as thyroid hormones
PO Iron Response- how fastvwill Pagophagia and RLS respond?
- Pagophagia and RLS will respond almost immediately
how long will it take for fatigue and energy to be improved after taking PO iron?
Fatigue and energy will improved within a few days
what it the PO iron response in regards to hemoglobin and iron stores?
- Hemoglobin will rise slowly after 1-2 weeks and the deficit should be halved within 1 month and return to normal within 6-8 weeks
- Iron stores may take 3-6 months to return to normal
what Select Indications for Parenteral Iron?
- Excessive continuing blood loss
- Inflammatory bowel diseases
- Chronic kidney disease
- Anemic cancer patients
- Patients intolerant or unresponsive to PO iron
- Large doses needed: estimated that only about 25 mg/d of elemental Fe can be absorbed via PO but up to 1000 mg can be given IV
- Known malabsorption states (e.g., celiac, GI bypass surgery, etc.)
Parenteral Iron: Products
- LMW iron dextran (INFeD, Cosmofer): IV/IM
- Ferric gluconate (Ferrlecit): IV
- Iron sucrose (Venofer): IV
- Ferumoxytol (Feraheme): IV
- Ferric carboxymaltose (Injectafer): IV
- Historically, many clinicians have been reluctant to use due to severe ADRs of older Parental iron formations such as?
anaphylaxis, shock, death
In parental iron, you often give test dose and pretreat with _____, if there is history of multiple allergies and/or asthma
IV steroid
Parenteral Iron: ADRs
**Anaphylactoid reactions: give test dose prior to infusion
o ~1% of patients
o More common with iron dextran v. ferric gluconate and iron sucrose
Delayed reactions (2-7 days) can occur o Fever, urticaria, arthralgias, lymphadenopathy
Others: chest pain, headache, hypotension, n/v/d, abdominal cramping
B12/Folate: Clinical Presentation
Macrocytic RBCs +/- anemia
Hypersegmented neutrophils
Unexplained neurologic signs and symptoms
o Dementia/delirium, weakness, sensory ataxia, paresthesias
B12/Folate: Risk Factors
- Elderly
- Alcoholics
- Malnourished
- Strict vegans
- Bariatric surgery
how to increase Vitamin B12 (Cyanocobalamin)
Foods with B12:
o Fortified foods and animal sources
Oral B12 OTC: could use in pt w/o neurologic sxs
o 1 mg cobalamin tablets
SubQ or IM Injection: pt w/ neurologic sxs
o Daily x 1 week, then weekly x 1 month, then monthly
How are ADRs of vitamin B12
usually well-tolerated
can get HA, N/V/D, hypokalemia
