Anemia Therapeutics Flashcards by David C

IDA treatment Aim

Replenish iron stores but also equally important is to identify what caused iron deficiency in the first place

How well did you know this?

Not at all

Perfectly

IDA: Treatment: Food

meat iron more absorbable

How well did you know this?

Not at all

Perfectly

IDA: Iron Supplement: What sort of tablets?

Enteric coated products and slow-release products are not reccomended. It would cause release too far distally.

How well did you know this?

Not at all

Perfectly

IDA: Iron Supplement: How to Take?

Best taken on an empty stomach as food interferes with absorption (see if you can tolerate it first)
But iron causes constipation, N/V/D, stomach upset, other intolerances. Just accept the fact they wont absorb it as well

How well did you know this?

Not at all

Perfectly

IDA: Iron Supplement: Dose?

Dose: 100-200 mg elemental iron per day, usually in 1-3 divided doses, for 3-6 months after anemia is resolved to build up iron stores. Due to poor tolerability, start lower and titrate up.
Evidence that low doses are just as effective in elderly patients.
Not dosing everyday (every other day) is just as good as dosing it everyday

How well did you know this?

Not at all

Perfectly

IDA: Treatment Table for doses

Differs between 3 products. Ferrous gluconate (35mg), ferrous sulfate (60mg), Ferrous fumarate (100mg)

How well did you know this?

Not at all

Perfectly

IDA: Treatment Table for doses: Iron polysaccharide

better absorbed and better marketed. Not a lot of good evidence…. but anadoctal evidence

How well did you know this?

Not at all

Perfectly

IDA: Treatment Table for doses: Heme Iron Polypeptide

Better absorbed, better tolerated, and less likely to interact with food. Have some clinical evidence for use. So only need 1-3 tabs day

How well did you know this?

Not at all

Perfectly

IDA: Treatment Table for doses:Iron bisglycinate

Better absorbed, better tolerated, and less likely to interact with food. Have some clinical evidence for use. So only need 1-3 tabs day

How well did you know this?

Not at all

Perfectly

IDA Treatment Guide

1st line is one of the top 3 traditional iron salts first. If patients cant tolerate iron salts, try the other 3.

How well did you know this?

Not at all

Perfectly

Strategies to improve tolerability

Increasing dosing interval
Switching formulations with lower amounts of elemental iron
Start at lower dose, then titrate up
Switching from tablet to liquid, easier titration
Dietary modifications (take with food or milk)- *sometimes better to take with food rather than stopping it !!!! *
Can switch to IV iron (usually saved as last resort)

How well did you know this?

Not at all

Perfectly

Drug Interactions with Oral Iron

Non heme iron required an acidic environment to be absorbed. Anything that decreases acidity might interact with this process.
Cholestyramine- bile acid diarrhea for gallbladder-less patients.

How well did you know this?

Not at all

Perfectly

How long do you separate iron from object drugs affected by iron?

2 hours

How well did you know this?

Not at all

Perfectly

IDA: Treatment: Oral Iron

Ferrous sulfate 75 mg/mL oral liquid (ODB)
Ferrous gluconate 300 mg tabs (ODB)
Ferrous fumarate 300 mg caps, 60 mg/mL liquid (ODB)
Iron polysaccharide complex caps, tabs, liquid, powder (not covered by ODB)
Proferrin® tabs (heme iron) (not covered by ODB)
Iron bisglycinate tabs (not covered on ODB)

How well did you know this?

Not at all

Perfectly

Parenteral Iron is reserved for patients who?

Are unable to* tolerate* or *absorb *oral iron
Have extensive chronic blood loss or extreme deficit in iron stores who cannot be maintained with oral iron alone
Need rapid correction of anemia
Also used in some patients with severe chronic kidney disease (esp. if on hemodialysis), some patients with cancer = evidence that it is better compared to oral !!

How well did you know this?

Not at all

Perfectly

Iron Deficiency Anemia: Treatment – Parenteral Iron

Iron dextran (Infufer®, Dexiron®)
IM – very painful, possible tissue staining
IV – hypersensitivity and anaphylactic reactions possible (test doses should be given)
[DISCONTINUED IN CANADA !!]

Iron Deficiency Anemia: Treatment – Parenteral Iron

**Iron sucrose (Venofer®)
**IV only, less likely to cause hypersensitivity reactions
* Test dose not required, but consider if the patient has a history of multiple drug allergies
* Officially indicated for treatment of IDA in CKD patients only

Iron Deficiency Anemia: Treatment – Parenteral Iron

Sodium ferric gluconate (Ferrlecit®)

Sodium ferric gluconate (Ferrlecit®)
* IV only, have caused hypersensitivity reactions in patients not undergoing hemodialysis
Test dose not required, but consider if the patient has a history of multiple drug allergies
Officially indicated for treatment of IDA in hemodialysis patients receiving supplemental EPO

Iron Deficiency Anemia: Treatment – Parenteral Iron

Iron isomaltoside (Monoferric®)

IV only, less likely to cause hypersensitivity reactions. VERY LOW so test dose not required
Benefit is that a full dose up to 1500mg or 20 mg iron/kg (whatever lower) can be given in one IV infusion session, unlike other available products
Officially indicated for any patient with IDA intolerant to oral therapy

Notes about Parenteral Iron

All are efficacious
Oral iron absorption decreased while on IV; stop oral if on IV therapy
All products carry a risk for anaphylactoid reactions (bronchospasm, pruritus/rash, anaphylactic shock) and infusion reactions (hypotension – most common, flushing, palpitations, shortness of breath, fever, nausea)
Should never be infused too quickly
– Transferrin binding sites can be overloaded, resulting in excess free iron in the bloodstream that can interfere with neutrophil function, perpetuate inflammatory reactions, and compromise active treatment of a coexisting infection

Iron Deficiency Anemia: Treatment – Parenteral Iron: Test Question: Female 70 kg, desired Hgb 13 g/dL, current Hgb 10 g/dL

Whats the total dose iron (mg) needed?

Total dose of iron (mg) = [(13-10) x 70 x 2.2] + 600  1000 mg
Don’t give all at one visit (exception: iron isomaltoside) ; usually in divideddoses of no more than elemental iron per dose (protocols
vary), > 48 hours between doses
– In clinical practice, max cumulative dose usually 1000-1500mg per 14-day period course, but protocols vary widely.

IV Iron infusion Pre-medication

Typically reserved for patients at highest risk (Hx of infusion reaction), (Asthma), ( >1 drug allergy)
If used, typically will include an IV steroid (e.g. methylprednisolone) +/- IV H2RA (e.g. ranitidine) OR IV H1RA (e.g. diphenhydramine)
Protocol is clinic-specific
Concern that s/e to premedication can mimic infusion reactions

IDA: Adverse Effects of Treatment : Oral

Primarily GI (loss of appetite, nausea, vomiting, constipation, stools may appear darker in color)
Liquid iron may temporarily stain the teeth – dilute and take through a straw to avoid staining

IDA: Adverse Effects of Treatment: IV

Immediate hypersensitivity reaction, anaphylaxis very rare
Serum sickness (lymphadenopathy, myalgia, arthralgia, fever, and headache) 4-48 hours after infusion
Hypotension/flushing associated with rapid injection

Monitoring for efficacy and safety: Oral iron therapy

Efficacy: Reticulocytosis within 5-7 days (not routinely monitored)- spike in reticulocytes will occur Monitor CBC/Ferritin every 1-2 months We want to see an Increase in 10 g/L of hemoglobin every 7–10 days --> If improved by less than 20 g/L over 3 weeks, investigate other causes of anemia Hgb should **reach normal** by *2 months* Ferritin should reach normal by 3-6 months Safety: Ongoing monitoring for GI intolerances -Usually occur within days-weeks of starting medication (usually starts right away, but pattern should be monitored for weeks). DONT say Monitor 3 months from now. !!!!!

Monitoring for efficacy and safety: Parenteral iron therapy | Efficacy and Safety

**Efficacy** Response time for anemia resolution with parenteral iron is generally similar to oral iron, but because IV iron circumvents absorption issues, Hgb rise is typically faster **Safety** Immediate hypersensitivity reaction monitoring (during and immediately after infusion); delayed hypersensitivity reaction **within 2 days after injection** Monitor monthly: ferritin, TSAT to assess for overload (ferritin>800 ng/mL; TSAT>50) Symptoms of iron overload, LFTs | general rule of thumb.

B12 Deficiency Anemia: What drug do we have to pay attention for?

Metformin. This medication causes decreased absorption. Check B12 levels once a year. Long term use will impact B12 levels. Use supplements often.

B12 Deficiency Anemia: Treatment Option 1: Parental IM Injection | ID and Dose?

Can give IM (Cyanocobalamin – synthetic form of B12) * 1000 µg IM daily for 1-2 weeks to saturate B12 stores, followed by 100-1000 µg per week until clinical manifestations resolve * Then monthly injections of 100-1000 µg until cause is resolved (potentially for whole life) * 1000 µg dose is often used by convention *** FOR PATIENTS WITHOUT ANEMIA**: (Lower dose, 1000 µg IM weekly until deficiency corrected, then once monthly thereafter)

B12 Deficiency Anemia: Treatment Option 2: Oral B12

**Lower dose Oral B12 + oral intrinsic factor** antibodies to intrinsic factor often prevent long-term success **Higher dose Oral B12 alone** can also be used due to an intrinsic factor independent absorption mechanism Large doses are required since the mean absorption rate in patients with pernicious anemia is 1.2%. 1000 - 2000 mcg/day. Can be given SL if patient prefers

B12 Deficiency Anemia: Treatment Option 3: Intranasal B12

**Intranasal B12 gel/spray (500 mcg/0.1 mL)** More bioavailable than the oral route 500 mcg in one nostril **once weekly** Do not administer within one hour before or after ingesting hot foods or beverages (increase nasal secretions and may cause the gel to be washed out of the nostril) Vitamin B12** levels should be checked one month** after 1 month; if levels decline, a higher dose may be required If used, suggest reserve for maintenance therapy after hematologic parameters have normalized

F &M : Vitamin B12 Deficiency Monitoring for Efficacy

Improved strength and well-being in a few days Bone marrow becomes normoblastic within 24 hours Reticulocytosis begins within 3-5 days Check CBC and serum Vit B12 levels in 1-2 months Hct/Hgb begins to rise within 2 wks, normalizing within 2 months Neurological function can improve within 24-48 hours, but complications can take months to years to resolve, and some may be irreversible

F &M : Vitamin B12 Deficiency Monitoring for Safety

Well tolerated, monitor inj site pain for IM and GI upset for PO Rare side effects: hyperuricemia and hypokalemia Elevated Vit B12 plasma levels associated with increased risk of cancer and mortality (causation not proven)