I2i / 22A09: Describe the pharmacology of 4% albumin
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