18A10: Exam Report

Outline the advantages (15% of marks) and disadvantages (85% of marks) of the clinical use of suxamethonium.

46% of candidates passed this question.

This commonly used drug should be very well-known. The question asked for an outline, hence long explanations of various aspects of pharmacology (e.g. pseudocholinesterase deficiency) were unnecessary.
Headings should have included: advantages (e.g. rapid onset, rapid offset, short acting, IV or IM administration, not end organ dependent for metabolism, premixed, safe in pregnancy and neonates). The disadvantages section should have included the following headings: pharmaceutical, adverse drug reactions (including several potentially fatal ones), numerous contraindications, unpleasant side-effects and potential problems with repeat dosing.

L2i / 18A10: Outline the advantages (15 marks) and disadvantages (85 marks) of the clinical use of suxamethonium

Definitions

Suxamethonium is a dicholine ester of succinic acid used for RSI

Ceutics

Advantages

Vial 100mg/2ml – easy to draw up dose by weight.  Also allows you to put 2 vials in 5ml red syringes which easily identifies muscle relaxant to avoid inadvertent drug administration. 

Disadvantages

Refrigerated – may be cumbersome to find in an emergency

Advantages

IM & IV administration

Disadvantages

PK

Advantages

Non-organ dependant elimination – very useful for ICU population

Disadvantages

Plasma cholinesterase deficiency will result in SUX Apnoea – a prolonged block which will require prolonged ventilation and ICU admission to wear off

Advantages

Rapid onset – can be used for RSI

Disadvantages

Fast offset – cannot be used for ongoing paralysis

PD

Advantages

Fasciculations – can easily see what patient is paralysed and ready to intubate

Disadvantages

Huge side effect profile, including side effects that can result in death; anaphylaxis & MH

Cardiovascular A/E – bradycardia, histamine release, hypotension

Numerous contraindications – burns, spinal injuries, critical illness myopathy, muscular dystrophies, renal failure

Tachyphylaxis – multiple doses progress to Ph II block

Myalgia