22A09: Exam Report

Describe the pharmacology of 4% albumin

41% of candidates passed this question.

This question required the candidate to consider 4% albumin from a pharmacological perspective.

The examiners were therefore after a description that included presentation, pharmaceutics (including correct content description and osmolality), indications, pharmacodynamics, pharmacokinetics, adverse effects, special precautions and dosing.

Albumin

Albumin

Chemical

Sterile, preservative free colloid solution

4% or 20% 

Separated from donated blood via chromatography 

70k Da

140 Na+ 

Hypoosmolar 

Stored below 30 degrees

Use

Volume replacement: peri-operative period, burns patient, trauma 

Resuscitation in severe sepsis

Presentation

4% (40g/L) or 20% (200g/L)

  • Excipients: Sodium 140 mmol/L, Chloride 120 mmol/L, Octanoate 6.4mmol/L

MoA

As a natural colloid already abundant in plasma, infused Albumin takes the same route

Normal translocation of albumin over endothelium to interstitium occurs

60% of albumin is located extravascularly

Albumin is transported back to circulation by lymphatic system

Albumin 5% expands Plasma volume by 80% the infused volume

Infusion of 10ml/kg albumin 5% increases serum albumin by 10% for 6-8hrs

PK

A – IV only

D 

After IV administration – rapid distribution within the vascular pool 

90% remains in intravascular compartment at 2hrs 

M – by cellular proteolysis 

E – degradation via liver 15%, renal 10%, leakage via GIT 10%, muscle + skin 40-60%. Degraded into amino acids -> amino acid pool

PD

As albumin is infused, its serum concentration falls rapidly – 50% dec by end of 1st day as albumin distributes to ECF  

Adverse Effects

Allergy

Infection risk

Bacteria, parasites and intracellular viruses are not transmitted because they are destroyed by freeze-thaw steps or removed by filtration

Pathogenic plasma-borne viruses such as HIV, HCV, Hep B, Hep A, Parovirus B19, and West Nile virus – at risk of transmission

Contraindications

Head injury (SAFE Study), previous immunological reactions, circulatory overload, oedema

Author: Zoe Guo / Krisoula Zahariou