Endocrine / Diabetes
Glucagon
Emergency treatment for severe low blood sugar — A rescue hormone that raises blood sugar fast when someone with diabetes is too unwell to eat or drink.
Education and reference only. This is a plain-language class overview — it deliberately contains no doses. Always check the current Summary of Product Characteristics (SmPC), the BNF and your local formulary before prescribing or administering any medicine.
Quick answer
What is Glucagon?
Glucagon is a hormone given as an emergency treatment to raise blood sugar quickly when someone with diabetes has a severe "hypo" and is too drowsy, unconscious or confused to eat or drink. It is given by injection or nasal powder by someone trained to help.
- How it works: Glucagon is the body's natural counterpart to insulin: it signals the liver to release its stored sugar (glycogen) into the blood, raising blood glucose within minutes.
- In practice: In practice glucagon is the emergency rescue treatment for severe hypoglycaemia (dangerously low blood sugar) in people on insulin or certain diabetes tablets, used when the person is confused, unconscious or fitting and so cannot safely swallow sugar.
What it is
Glucagon is a hormone given as an emergency treatment to raise blood sugar quickly when someone with diabetes has a severe "hypo" and is too drowsy, unconscious or confused to eat or drink. It is given by injection or nasal powder by someone trained to help.
How it works
Glucagon is the body's natural counterpart to insulin: it signals the liver to release its stored sugar (glycogen) into the blood, raising blood glucose within minutes. Because it draws on the liver's store, it works well when those stores are full but poorly when they are depleted by fasting, alcohol or repeated hypos.
In practice
In practice glucagon is the emergency rescue treatment for severe hypoglycaemia (dangerously low blood sugar) in people on insulin or certain diabetes tablets, used when the person is confused, unconscious or fitting and so cannot safely swallow sugar. It is given by injection or, increasingly, as a nasal powder, by a family member, friend or carer who has been shown how — so the practical work is training those around the person and keeping an in-date kit accessible. After giving it, an ambulance is called if the person does not wake quickly, and the moment they are awake enough to swallow they are given longer-acting carbohydrate (and their usual treatment reviewed) because the effect is temporary and the sugar can fall again. A key limitation to counsel on: glucagon works by releasing stored sugar from the liver, so it works poorly when those stores are empty — after prolonged fasting, heavy alcohol, or repeated recent hypos — where intravenous glucose is needed instead. Nausea and vomiting after waking are common. Glucagon is also used in some other emergencies (such as certain beta-blocker overdoses) and to relax the gut for some scans.
Examples
Practical use
How to take it & use it well
- Use it as an emergency rescue when someone with diabetes has a severe hypo and cannot safely swallow food or drink, such as being drowsy, confused, fitting or unconscious.
- Give it as you have been trained, either as an injection or a nasal spray, following the simple steps in the kit, and call 999 if you are unsure or the person does not improve.
- Place the person on their side while you act, so that if they are sick they do not choke, and stay with them throughout.
- Once they wake and can swallow safely, give a sugary drink or snack followed by some longer-acting carbohydrate, as the effect of glucagon is only temporary.
- If there is no response within a short time, call 999, as they will need glucose given into a vein by paramedics.
- Replace the kit before it expires and make sure carers, family or colleagues know where it is and have been shown how to use it.
Common uses
- Severe hypoglycaemia when the person cannot swallow
- Carried by people at risk of severe hypos and their carers
- Some other emergencies and gut relaxation for imaging
Monitoring
- Recovery of consciousness and blood sugar after use
- Follow-up carbohydrate and review of the cause of the hypo
- That carers are trained and the kit is in date and accessible
Weighing it up
Advantages & disadvantages
Advantages
- It can rescue someone from a severe hypo when they are too unwell to eat or drink.
- It can be given by a trained family member or carer, not only by medical staff.
- It comes in easy-to-use forms, including a nasal spray that needs no injection.
- It buys vital time while waiting for an ambulance in a diabetes emergency.
- It is a well-established part of the safety net for people on insulin.
Disadvantages
- Its effect is temporary, so longer-acting food is needed afterwards to stop the hypo returning.
- It works poorly when the body's sugar stores are empty, such as after fasting, heavy drinking or repeated hypos.
- Feeling sick or vomiting after waking is common, which can make taking food afterwards harder.
- It does not work for low blood sugar caused by things other than too much insulin or diabetes medicine.
- The kit must be kept in date and to hand, or it is of no use in an emergency.
Key safety principles
What to watch for
- For severe hypos when the person cannot safely swallow — give it, then call an ambulance if they do not wake quickly.
- The effect is temporary — once awake enough, give longer-acting carbohydrate and review treatment, as blood sugar can fall again.
- Works poorly when liver sugar stores are empty (prolonged fasting, alcohol, repeated hypos) — intravenous glucose is needed then.
Key interactions
What to avoid or check alongside
- Because its effect is temporary, longer-acting carbohydrate must follow once the person can swallow, or the hypo can come straight back.
- It works poorly when the body's stores of sugar are low, as after fasting, alcohol or repeated hypos, when glucose given into a vein is needed instead.
- Carers and family should be trained in advance, as the person having the hypo usually cannot give it to themselves.
- Keep the kit in date and stored as instructed, replacing it before it expires so it works when needed.
- Call 999 if the person does not wake within a short time, as professional treatment with intravenous glucose is then required.
Patient & carer advice
- Make sure people around you know where your kit is and how to use it
- After it works and you can swallow, eat some longer-lasting carbohydrate to stop your sugar dropping again
- Call 999 if you do not come round quickly, and tell your diabetes team about any severe hypo
Use with
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Answers
Glucagon: frequently asked questions
When should glucagon be used?
It is for a severe hypo, when someone with diabetes has blood sugar so low that they cannot safely eat or drink, for example if they are very drowsy, confused, fitting or unconscious. In that situation, a trained carer gives glucagon and calls for help. For milder hypos, sugary food or drink is used instead.
What do I do after glucagon wakes someone up?
Its effect is only temporary, so once the person is awake and can swallow safely, give them a sugary drink or snack and then some longer-acting carbohydrate, such as a sandwich or biscuits. This stops the hypo returning. Keep watching them and seek advice if they are unwell.
Why might glucagon not work?
Glucagon works by releasing the body's stored sugar, so it works poorly when those stores are empty, such as after fasting, heavy alcohol use or repeated hypos. In these cases it may not bring someone round, and they need glucose given into a vein by paramedics, so always call 999 if there is no response.
Can a family member give glucagon?
Yes. Glucagon is designed so that a trained family member or carer can give it in an emergency, as the person having the hypo usually cannot help themselves. Make sure those around you know where the kit is, that it is in date, and how to use the injection or nasal spray.
Is it normal to feel sick afterwards?
Yes, feeling sick or even vomiting after waking is common with glucagon. Keep the person on their side until they are fully alert so they do not choke, and once they feel able, encourage them to take sugary then longer-acting food. Seek advice if the sickness stops them eating.
Authoritative sources
Always verify against the source
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