Adrenaline

A hormone, also used as a medicine, that narrows small blood vessels. Mixed with a local anaesthetic, it reduces bleeding where it is injected and can make the numbness last longer. In hand surgery it allows many operations to be done without a tourniquet. Its effect builds up over the first half-hour or so after injection and wears off over several hours.

Related terms

• Treatment

  WALANT

  Wide-awake local anaesthesia no tourniquet. Lignocaine with adrenaline is injected at the operation site, so a hand operation can be done without a tourniquet, sedation or a general anaesthetic. The patient stays awake and can move the hand when asked, so the surgeon can check movement before the skin is closed. Whether it suits a particular person depends on the operation, their circulation and general health, and their preference.

• Glossary

  Tourniquet

  An inflatable cuff placed around the upper arm or forearm and pumped up to keep the operating area free of blood, giving the surgeon a clear view. An inflated tourniquet is uncomfortable for an awake person, so it is often combined with a regional block, sedation or a general anaesthetic. WALANT avoids it by using adrenaline instead.

• Treatment

  Phentolamine

  A medicine that reverses the narrowing of blood vessels caused by adrenaline. If a finger stays pale after an injection of local anaesthetic with adrenaline, phentolamine injected at the same site helps its colour return sooner. In a large prospective series of hand surgery with adrenaline it was never needed.

Articles mentioning this term

1. Clinician education · 11 October 2026

   Hand surgery under local anaesthesia (WALANT)

   How wide-awake local anaesthesia no tourniquet (WALANT) works for hand surgery, what the evidence shows, its limits, and who it may suit.

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