Lidocaine with adrenaline

How it works

Lidocaine blocks neuronal sodium channels to prevent nerve conduction, while adrenaline causes local vasoconstriction that slows systemic absorption, prolonging anaesthesia and limiting bleeding.

Prescribing in practice

• Because of the adrenaline-induced vasoconstriction, it must not be used in or around end-arterial sites such as digits, the nose tip, ears, penis and skin flaps, where ischaemic necrosis can result.
• Always aspirate before injection and use the lowest effective dose, as inadvertent intravascular injection can cause local anaesthetic systemic toxicity.
• Use caution where systemic adrenaline absorption is hazardous, such as severe cardiovascular disease, and with drugs that potentiate adrenaline.

Monitoring

Monitor for local anaesthetic systemic toxicity (perioral tingling, dizziness, arrhythmias, seizures) and assess perfusion of the anaesthetised area.

Counselling the patient

• This injection numbs the area and the added adrenaline makes it last longer with less bleeding.
• Tell us immediately if you feel dizzy, develop ringing in the ears or a metallic taste, or notice palpitations.
• Numbness will wear off gradually; protect the area from injury until sensation returns.

Evidence & guidelines

Avoidance of adrenaline-containing local anaesthetic in end-arterial sites is long-established safe-practice guidance.