Mepivacaine with adrenaline

How it works

Mepivacaine blocks neuronal voltage-gated sodium channels to produce local anaesthesia, while the added adrenaline causes local vasoconstriction that slows systemic absorption, prolongs the block and reduces bleeding.

Prescribing in practice

• Because of the adrenaline component, it must not be injected into or near end-arterial sites such as digits, nose, ears or penis where vasoconstriction can cause ischaemic necrosis.
• The adrenaline can provoke palpitations, hypertension and arrhythmia, so use cautiously in cardiovascular disease, hyperthyroidism, and in patients on tricyclic antidepressants or non-selective beta-blockers where pressor effects may be exaggerated.
• As with all amide local anaesthetics, aspirate before injection and respect the maximum safe dose to avoid local anaesthetic systemic toxicity.

Monitoring

Monitor for systemic local anaesthetic toxicity and for adrenaline-related cardiovascular effects such as tachycardia and hypertension.

Counselling the patient

• Numbness will last longer than with a plain local anaesthetic; protect the numb area until feeling returns.
• A short-lived racing heartbeat after injection can occur because of the adrenaline.
• Report dizziness, a metallic taste, ringing in the ears or tingling around the mouth at once.

Evidence & guidelines

Adding adrenaline to amide local anaesthetics to prolong block duration and limit systemic absorption is long-established practice; avoidance of adrenaline-containing solutions at end-arterial sites is a standard safety principle.