Prilocaine with felypressin

How it works

Prilocaine blocks neuronal sodium channels to produce local anaesthesia, while felypressin (a vasopressin analogue) causes local vasoconstriction that prolongs anaesthesia and reduces systemic absorption and bleeding.

Prescribing in practice

• As with prilocaine generally, excessive doses risk methaemoglobinaemia, so observe maximum recommended quantities and avoid in patients prone to methaemoglobinaemia.
• Felypressin can cause coronary and other vasoconstriction, so use with caution in severe ischaemic heart disease; it is a preferred adrenaline-free alternative when catecholamine-related effects are a concern.
• Caution is advised in pregnancy because felypressin has theoretical oxytocic-like activity at high doses.

Monitoring

Observe for systemic local anaesthetic effects and cyanosis suggesting methaemoglobinaemia, particularly if repeated injections are needed.

Counselling the patient

• Explain the area will be numb for a while and to avoid biting the lip, cheek or tongue or taking hot food until sensation returns.
• Report any dizziness, palpitations or unusual blue discolouration of the lips or skin.

Evidence & guidelines

Prilocaine with felypressin is an established dental anaesthetic option, valued where an adrenaline-containing preparation is best avoided.