In short: a nerve block is an injection of local anaesthetic near the nerves that supply the part being operated on. It usually makes the limb numb and weak for several hours, and sometimes for a day or more. Protect the numb limb from knocks, heat and cold, do not walk on a weak leg without help, and have your pain relief plan ready before the block wears off.
What a nerve block is
A nerve block is a type of regional anaesthetic. Your anaesthetist injects local anaesthetic, sometimes with other pain-relieving medicine, close to the major nerves that supply the area. An ultrasound scanner or a nerve stimulator is usually used to guide a fine needle to the right place.
Where the injection goes depends on the operation. healthdirect lists these common sites:
- Arm, hand and shoulder: the side of the neck, near the collarbone or armpit, or at the elbow, forearm or wrist.
- Hip, knee, ankle and foot: near the groin, behind the knee, or at the ankle or foot.
More than one injection may be needed. Sometimes a very thin tube (catheter) is left in place so more local anaesthetic can be given, which lets the block last longer.
A block can be the main anaesthetic for some operations, or it can be added to sedation, a spinal or a general anaesthetic, mainly for pain relief afterwards. Australia’s hip fracture clinical care standard recommends nerve blocks for people with a broken hip unless they are unsuitable, because they reduce the amount of opioid medicine needed and the side effects that come with it, such as drowsiness and confusion.
Two effects: numb and weak
healthdirect describes two effects. The block numbs the nerves that carry pain and touch, which is what gives pain relief. It can also affect the nerves that move the muscles, so the limb feels heavy and weak. ANZCA notes that the heaviness usually goes within a few hours, while numbness and tingling can last much longer.
How long it lasts
There is no single answer. It depends on the medicines used, where the injection was given and whether you have a catheter.
| Type of block | What the sources say |
|---|---|
| A single injection | From about 3 to 24 hours or longer, depending on the injection site and the medicines used (Townsville Hospital and Health Service). |
| Continuous or repeated doses, through a catheter | How long the block lasts depends partly on whether the local anaesthetic is given continuously or repeated. Numbness typically lasts several hours but may last several days (ANZCA). |
| Slow nerve recovery | Uncommonly, numbness or weakness lasts for weeks to months while the nerve recovers (Townsville Hospital and Health Service). |
Before you leave the operating theatre or the hospital, ask how long your block is expected to last and write the answer down. It tells you when to expect feeling to return, and when a numb limb has gone on longer than it should.
Plan for the block wearing off
As the block fades you may notice tingling, then the ache of the operation returning. ANZCA notes that pain from surgery may come back as the numbness wears off, and that other pain relief, such as tablets or injections, is prescribed for this. The Australian Society of Anaesthetists advises asking for pain relief when discomfort starts rather than waiting until it is severe.
Before the block wears off
- Know which pain medicines you have been prescribed, what each is for, and when to take them.
- Ask whether you should start regular pain relief before the feeling returns. Many plans do, but follow your own.
- If you are at home, keep your medicines, a glass of water and your phone within reach, especially overnight.
- Know who to call if the pain is not controlled.
Read pain relief and the first two weeks at home for how a pain plan usually steps down.
Looking after a numb arm or hand
A numb limb cannot warn you when it is being hurt. The Townsville Hospital and Health Service fact sheet gives three rules: support a weak arm in a sling, avoid bumping or injuring the numb area, and keep hot or very cold things off it, because you will not feel a burn.
- Wear the sling as you were shown, and check that your hand and fingers are not squashed or hanging over an edge.
- Take care with hot drinks, hot water, ovens and heaters while your hand is numb.
- Do not put a heat pack or an ice pack straight onto skin you cannot feel. Use them only as your surgeon or physiotherapist advises.
- Lie so that the arm is supported and is not trapped under you.
Looking after a numb leg or foot
- Do not walk without someone to help you while the leg is weak. A numb leg can give way without warning.
- Use any walking aid exactly as the physiotherapist showed you.
- Protect your heel and foot from pressure, knocks and heat until the feeling returns.
- Ask for help the first time you get up after the operation.
After an arm or shoulder block: voice, eyelid and breathing
healthdirect lists a hoarse voice, a droopy eyelid on the same side as the block, and changes in breathing among the possible effects of an arm block. They improve as the block wears off. The Australian Society of Anaesthetists notes that, rarely, the side of the face may feel numb after a shoulder block, and that this passes. Tell your anaesthetist beforehand if you have a lung condition or get short of breath easily, and tell the nurses straight away if your breathing feels different.
Risks
healthdirect describes nerve blocks as usually giving effective pain relief during and after the operation. Like any procedure they carry risks, and some are higher for people who are older, are obese, smoke, or have diabetes, heart disease or lung disease.
| How often | What can happen |
|---|---|
| Common | A small bruise where the needle went in, more likely if you take blood-thinning medicine. Numbness and weakness while the block works. |
| Uncommon | The block does not work fully, and another injection or a different kind of pain relief is needed. A nerve that is slow to recover, with numbness or weakness for weeks to months. |
| Rare | Nerve damage. healthdirect says it is usually temporary, lasting up to 12 weeks, but sometimes lasts longer than 6 months or is permanent. Allergic reaction, bleeding, a reaction to the local anaesthetic itself (light-headedness or a seizure), problems with vision and, with some arm blocks, air around the lung (pneumothorax). |
Your anaesthetist can tell you which of these apply to the block they suggest, and whether your own risk is higher or lower than average.
When to get help
Call 000 if you have sudden shortness of breath, chest pain, a seizure, or someone cannot wake you.
Contact the hospital where you had your operation, or your surgeon or anaesthetist, if:
- the numbness or weakness lasts longer than you were told to expect
- the pain is not controlled by the medicines you were given
- the injection site becomes red, hot, swollen or oozes, or you develop a fever
- you have any other concern about the limb.
If you cannot reach them, see your GP or go to an emergency department. healthdirect’s nurse advice line is 1800 022 222, day or night.
Common questions
Can I be asleep or sedated while the block is put in and during the operation?
A nerve block can be the only anaesthetic for some operations, or it can be combined with sedation or a general anaesthetic. Ask your anaesthetist which combination they suggest for your operation and why.
What happens if I would rather not have a nerve block?
Your anaesthetist can suggest other ways to manage pain. healthdirect notes that without a block you may need more of the stronger pain medicines during and after surgery, and these are more likely to cause nausea or drowsiness. A block may also be unsuitable for some people, for example if they are allergic to the medicines or materials used, or have an infection where the needle would go.
Can I go home before the block has worn off?
Sometimes, particularly after day surgery on the hand, arm or foot. If you do, you should be told how long the numbness is expected to last, how to protect the limb, which pain relief to take and when, and who to call. Ask for this in writing if it is not offered.
The block has worn off and the pain is worse than I expected. What should I do?
Take the pain relief you were prescribed, as directed. If it is not controlling the pain, contact the hospital or your surgeon's rooms for advice rather than waiting. In an emergency, call 000.
Sources
- healthdirect Australia. Peripheral nerve block (upper limb). Last reviewed Jan 2026.
- healthdirect Australia. Peripheral nerve block (lower limb). Last reviewed Jan 2026.
- ANZCA. Types of anaesthesia (patient information). Page modified 30 Sep 2025.
- ANZCA. Anaesthesia for joint surgery (patient information). Page modified 30 Sep 2025.
- Townsville Hospital and Health Service (Queensland Health). What is a nerve block? (anaesthetic department fact sheet, version 2). Last reviewed Feb 2026.
- Australian Society of Anaesthetists. Anaesthesia for shoulder joint replacement surgery (patient information pamphlet). Last reviewed 12 Mar 2024.
- Australian Society of Anaesthetists. Epidural and spinal anaesthesia and analgesia (patient information pamphlet). Last reviewed 12 Mar 2024.
- Australian Commission on Safety and Quality in Health Care. Hip Fracture Clinical Care Standard (2023). 2023.
- Written by
- Altitude Creative, health content team, on behalf of Dr Walid Aly
- Clinical reviewer
- In progress
- Review date
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- Set at clinical review
How this guide is written, reviewed and corrected: editorial policy.
In an emergency, call 000. This information is general and does not replace advice from your treating practitioner.