01.08.2 Intra-Arterial

The main disadvantage of intra-arterial injection (injection into an artery) is that it requires great care, and should only be done by experts. If you get it wrong, there will be blood everywhere! Intra-arterial (i.a.) injections are used to localise effects of a drug to a particular tissue or organ e.g. in the treatment of renal tumours or head/neck cancers, drugs can be injected into the renal artery or carotid artery, respectively. After intra-arterial administration, the highest concentrations are localised and have their maximum effect locally. As the drug moves away from its site of injection, it is diluted in the circulation, and this reduces the toxicity of the drug. Another advantage of intra-arterial injection to the site of action is that it avoids first pass liver and lung metabolism.