A daily injection for acromegaly
Pegvisomant
A daily self-injection used to treat acromegaly by blocking the effects of growth hormone in the body.
What is Pegvisomant?
Pegvisomant is a specialist medicine used to treat acromegaly, a condition in which the body produces too much growth hormone, usually because of a benign pituitary tumour. Unlike treatments that lower growth hormone levels, it works by blocking growth hormone's effect on the body, which lowers a related hormone called IGF-1 that drives the symptoms. It is given as a daily injection under the skin, usually by the person themselves after training. The main thing the specialist team watches for is changes in liver blood tests, so the liver is monitored regularly.
Education and reference only. This is a plain-language guide to Pegvisomant — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Pegvisomant is a medicine used to treat acromegaly, a condition where a usually non-cancerous tumour of the pituitary gland produces too much growth hormone. Over years this causes changes such as enlarged hands, feet and facial features, along with other health problems. Pegvisomant is a growth hormone receptor blocker, meaning it stops growth hormone acting rather than reducing how much is made. It is given as a daily injection under the skin and is generally used when surgery, radiotherapy or other medicines have not controlled the condition well enough. It is prescribed and supervised by an endocrine specialist team.
How it works
Growth hormone causes its effects by attaching to receptors, mainly in the liver, which then make a hormone called IGF-1; in acromegaly it is largely IGF-1 that drives the symptoms. Pegvisomant attaches to these growth hormone receptors and blocks them, so growth hormone cannot signal properly and the body makes less IGF-1. As IGF-1 falls towards normal, the symptoms of acromegaly tend to improve. Because it blocks growth hormone's action rather than its production, measured growth hormone levels in the blood may actually rise, so treatment is judged by IGF-1 levels and symptoms rather than growth hormone levels.
Company & origin
Originated / developed by: Specialist manufacturer.
A specialist injection used in the UK to treat acromegaly, a condition of excess growth hormone, usually when other treatments have not worked well enough.
Practical use
How to take Pegvisomant
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Inject it under the skin once a day as your specialist team has trained you, using a fresh site each time.
- Rotate where you inject to reduce skin reactions and lumps; do not always use the same spot.
- Attend your regular blood tests, as the team checks your liver and IGF-1 to keep treatment safe and effective.
- Report any yellowing of the skin or eyes, dark urine, severe tiredness or tummy pain straight away.
- If you have diabetes, monitor your blood sugar as advised, as your diabetes treatment may need adjusting.
Weighing it up
Advantages & disadvantages of Pegvisomant
Advantages
- Effectively controls the symptoms of acromegaly by blocking growth hormone's action and lowering IGF-1.
- A useful option when surgery, radiotherapy or other medicines have not worked well enough.
- Can be self-injected at home after training.
Disadvantages
- Can raise liver blood tests, so the liver must be monitored regularly.
- Needs a daily injection and ongoing specialist supervision.
- Does not shrink the pituitary tumour, which still needs to be monitored separately.
Practical use
Good to know
A key point to understand with pegvisomant is that it works by blocking growth hormone's action, so the team measures IGF-1 and your symptoms to judge whether it is working, rather than the growth hormone level itself. The most important safety issue is its effect on the liver: it can raise liver enzymes, so liver blood tests are checked before starting and regularly during treatment, and any yellowing of the skin or eyes, dark urine, severe tiredness or tummy pain should be reported promptly. Reactions where the injection is given, and occasionally fatty lumps under the skin if it is always injected in the same spot, are common, so rotating injection sites helps. Because it can change how the body handles blood sugar, people with diabetes may need their diabetes treatment reviewed. It does not shrink the pituitary tumour, so the tumour is also monitored.
Who should not take it / use with caution
- People who have had a serious allergic reaction to pegvisomant should not use it.
- It is used with particular caution, and with closer monitoring, in people with existing liver problems.
- It is used in pregnancy only where the benefit is judged to outweigh the risk, under specialist guidance.
Monitoring
- Liver blood tests before starting and regularly during treatment.
- IGF-1 levels and symptoms to judge how well treatment is working.
- Scans to monitor the size of the pituitary tumour over time.
Side effects
- Redness, pain or swelling where the injection is given, and sometimes lumps under the skin if the same site is overused.
- Raised liver blood tests, which is why the liver is monitored.
- Headache, tiredness, joint aches or stomach upset in some people.
- Changes in blood sugar control, which may matter for people with diabetes.
Key interactions
- It can change how the body handles blood sugar, so diabetes medicines, including insulin, may need adjusting.
- Tell your team about all your medicines, as treatment for acromegaly is often combined and reviewed together.
- Other medicines that affect the liver are taken into account when monitoring liver blood tests.
Available as: A powder made up into a solution for injection under the skin, usually given by the patient.
Answers
Pegvisomant: frequently asked questions
What is pegvisomant used for?
It is used to treat acromegaly, a condition of too much growth hormone, usually when surgery, radiotherapy or other medicines have not controlled it well enough.
How is it different from other acromegaly treatments?
Rather than lowering how much growth hormone is made, it blocks growth hormone from acting, which lowers the hormone IGF-1 that drives the symptoms.
Why are my liver tests checked so often?
Pegvisomant can raise liver enzymes, so the liver is monitored before and during treatment; report any yellowing of the skin or eyes, dark urine or severe tiredness straight away.
Why do they measure IGF-1 instead of growth hormone?
Because the medicine blocks growth hormone's action, the growth hormone level can rise, so the team uses IGF-1 and your symptoms to judge whether it is working.
Can I inject it myself?
Yes, most people inject it under the skin themselves each day after their specialist team has trained them, rotating the injection site.
Authoritative sources
- BNF
- NICE CKS
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