2003A04 Outline the potential problems associated with additives used to make medicines suitable for intravenous injection.

Drug

Purpose

Problem

Sodium metabisulfite

Lignocaine, adrenaline

Anti-oxidant, anti-microbial

·   Anaphylaxis

Egg lecithin

Propofol

Emulsifier

·   ?Anaphylaxis

·   Protein deplete; theoretical risk

Benzethonium chloride

Ketamine

Antimicrobial

·   ?Neurotoxicity

Propylene glycol

Etomidate, diazepam, digoxin, phenytoin

Solubiliser

·   Pain on injection

·   Thrombophlebitis

Soybean oil

Propofol

Solubiliser

·   Lipotoxicity

·   Bacterial contamination risk

·   Propofol infusion syndrome

Mannitol

Paracetamol

Tonicity

·   Osmotic diuresis

Glycine

Remifentanil

Bulk agent

·   Neurotoxic (not for intrathecal use)

↑pH, ↑concentration

Thiopentone

·   Precipitation if intra-arterial injection

·   Necrosis if extravasation

·   Precipitation with acidic drugs e.g. suxamethonium