Telotristat ethyl

How it works

Its active metabolite inhibits tryptophan hydroxylase, the rate-limiting enzyme in serotonin synthesis, reducing peripheral serotonin production that drives carcinoid-related diarrhoea.

Prescribing in practice

• Because reducing serotonin can affect mood, depression and reduced mood have been reported, and patients should be monitored for and advised to report such symptoms.
• Gastrointestinal effects including nausea and abdominal pain are common, and constipation can occur as diarrhoea improves.
• Liver enzyme elevations have been observed, so hepatic function should be considered during treatment.

Monitoring

Monitor stool frequency and clinical response, together with mood and liver function, during treatment.

Counselling the patient

• Take the medicine with food as directed and continue your somatostatin analogue treatment.
• Report low mood or depression to your clinical team.
• Tell your team if constipation or persistent abdominal pain develops.

Evidence & guidelines

The TELESTAR trial demonstrated reduced bowel movement frequency in carcinoid syndrome diarrhoea, consistent with the SPC and NICE appraisal.