A medicine that reduces serotonin to control carcinoid-syndrome diarrhoea
Telotristat ethyl
A specialist medicine used to control the diarrhoea of carcinoid syndrome by reducing serotonin production.
What is Telotristat ethyl?
Telotristat ethyl is a specialist medicine used to control the diarrhoea of carcinoid syndrome, a condition caused by certain hormone-producing tumours that make too much serotonin. It works by blocking an enzyme (tryptophan hydroxylase) so the body makes less serotonin, which eases the diarrhoea. It is taken by mouth, usually alongside another treatment called somatostatin analogues. Because it reduces serotonin, it can cause constipation, which can occasionally become severe, as well as nausea and low mood; liver blood tests are also checked. It is used under specialist care.
Education and reference only. This is a plain-language guide to Telotristat ethyl — 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
Telotristat ethyl is a medicine used to help control the diarrhoea that troubles people with carcinoid syndrome. Carcinoid syndrome is caused by certain slow-growing tumours (neuroendocrine tumours) that release too much serotonin and other substances, which leads to frequent, watery diarrhoea. Telotristat ethyl reduces the amount of serotonin the body makes, which helps when diarrhoea is not fully controlled by standard treatment. It is taken by mouth as a tablet, usually in addition to somatostatin analogues, and is prescribed and monitored by a specialist team.
How it works
Serotonin is made from an amino acid using an enzyme called tryptophan hydroxylase. In carcinoid syndrome, the tumours overproduce serotonin, which drives the diarrhoea. Telotristat ethyl blocks this enzyme, so less serotonin is produced, which reduces the diarrhoea over time. Because it lowers serotonin throughout the body, it can have knock-on effects such as constipation and changes in mood, which is why these are watched. It is added to existing treatment rather than replacing it, and its benefit on bowel symptoms is judged over the early weeks.
Company & origin
Originated / developed by: Specialist manufacturer.
A specialist medicine used to control the diarrhoea of carcinoid syndrome by reducing the body's production of serotonin.
Practical use
How to take Telotristat ethyl
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it by mouth with food as prescribed, usually in addition to your existing carcinoid treatment.
- Report any marked constipation, tummy pain or bloating promptly, as constipation can occasionally become severe.
- Tell your team about any low mood or changes in how you feel, as it can affect mood.
- Attend appointments for liver blood tests before and during treatment.
- Do not stop your other treatments, such as somatostatin analogues, unless your specialist advises.
Weighing it up
Advantages & disadvantages of Telotristat ethyl
Advantages
- Helps control the diarrhoea of carcinoid syndrome when standard treatment is not enough.
- Taken by mouth and added on top of existing treatment.
- Targets the overproduction of serotonin that drives the symptoms.
Disadvantages
- Can cause constipation, which occasionally becomes severe, as well as nausea.
- Can lower mood or cause depression in some people.
- Can raise liver blood tests, which need monitoring, and is a specialist-only medicine.
Practical use
Good to know
Because telotristat ethyl works by lowering serotonin to reduce diarrhoea, the flip side is that it can cause constipation, and occasionally this can become severe, so any marked constipation, tummy pain or bloating should be reported promptly rather than left. Nausea is common, particularly early on. As serotonin also influences mood, it can sometimes cause low mood or depression, so any changes in mood should be mentioned to the team. The medicine can raise liver blood tests, so these are checked before and during treatment. It is usually taken with food and added on top of somatostatin analogue treatment rather than instead of it. It is a specialist medicine, used under the care of a team familiar with neuroendocrine tumours, with regular review.
Who should not take it / use with caution
- People who have had a serious allergic reaction to telotristat ethyl should not take it.
- It is used with caution in people prone to constipation or with a history of low mood.
- It should only be used under a specialist team familiar with neuroendocrine tumours.
Monitoring
- Reviewing how well the diarrhoea responds over the early weeks of treatment.
- Watching for constipation, tummy pain and any changes in mood.
- Liver blood tests before and during treatment.
Side effects
- Constipation, which can occasionally become severe, and tummy pain or bloating.
- Nausea, headache, tiredness or reduced appetite.
- Low mood or depression, and raised liver blood tests.
Key interactions
- It can change the levels of some other medicines, so a full medicines list is important.
- It is used alongside, not instead of, somatostatin analogue treatment under specialist advice.
- Tell your team about all your medicines, including any for mood, before starting.
Available as: Tablets taken by mouth, usually with food.
Answers
Telotristat ethyl: frequently asked questions
What is telotristat ethyl used for?
It is used to help control the diarrhoea of carcinoid syndrome by reducing the body's production of serotonin, usually alongside other treatment.
Why can it cause constipation?
Because it lowers serotonin to reduce diarrhoea, the bowel can swing the other way and become constipated; this can occasionally be severe, so report marked constipation or tummy pain promptly.
Does it replace my other treatment?
No. It is usually added on top of treatments such as somatostatin analogues rather than replacing them, so keep taking your other medicines unless your specialist advises otherwise.
Can it affect my mood?
Because serotonin also influences mood, it can sometimes cause low mood or depression, so tell your team about any changes in how you feel.
Why are my liver tests checked?
Telotristat ethyl can raise liver blood tests, so these are checked before and during treatment to keep an eye on your liver.
Authoritative sources
- BNF
- NICE CKS
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