Telotristat Ethyl
Pronunciation: (zer-MEH-loh).
- Generic name
- telotristat ethyl
- Brand names
- Teloxer, Telozest, Xermelo, Telotri
- Drug class
- Tryptophan hydroxylase inhibitor (antidiarrheal for carcinoid syndrome)
Availability and supply rules vary by country
Trade names by country: United States
Australia: · Full directory
What telotristat ethyl is and how it works
Uses, formulations, monitoring, and supply rules can differ by patient, product, and country. Follow the exact local product information and professional advice.
Mechanism of action: how telotristat ethyl works
Telotristat ethyl, the active ingredient in Xermelo, is a prodrug that is converted to telotristat, a potent inhibitor of tryptophan hydroxylase. This enzyme is the rate-limiting step in serotonin biosynthesis. By inhibiting tryptophan hydroxylase, telotristat reduces peripheral serotonin production, which is implicated in the pathophysiology of carcinoid syndrome diarrhea. (1)
What telotristat ethyl is used for
Carcinoid syndrome diarrhea
Carcinoid syndrome diarrhea (1)
Diarrhea associated with neuroendocrine tumors
Diarrhea associated with neuroendocrine tumors (1)
Symptomatic treatment of carcinoid syndrome
Symptomatic treatment of carcinoid syndrome (1)
Before taking telotristat ethyl
Do not take / not appropriate for
- Contraindicated in patients with known hypersensitivity to telotristat ethyl or its components. Use caution in patients with moderate to severe hepatic impairment due to increased risk of adverse effects. (Contraindication) (1)
- Not recommended in pediatric patients. (Contraindication) (1)
- Use in pregnancy and lactation only if benefits outweigh risks. (Contraindication) (1)
Tell your clinician about
(1)How to take telotristat ethyl
- General Instructions: Take Xermelo exactly as prescribed by your doctor, usually three times daily with food.. Adult Dosing: The recommended dose for adults is 250 mg orally three times daily with food.. Pediatric Dosing: Safety and effectiveness in children under 18 years have not been established; use is not recommended in pediatric patients.. Administration: Swallow the tablet whole with a glass of water. Do not crush, chew, or split the tablet.. When To Stop: Do not stop taking Xermelo without consulting your doctor, even if you feel better. Discontinue only under medical supervision.. Storage: Store at room temperature (20°C to 25°C/68°F to 77°F), away from moisture and heat. Keep out of reach of children.
- This page does not provide a dose calculator. Dosing must follow the prescriber, pharmacist, or product label.
Procedures and treatment changes
Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1)
Missed dose
If you miss a dose of Xermelo, take it as soon as you remember with food. If it is almost time for your next dose, skip the missed dose and resume your regular schedule. Do not take two doses at once.
Overdose
In case of overdose, seek emergency medical attention or contact your local poison control center immediately. Symptoms may include severe abdominal pain, worsening diarrhea, or signs of liver dysfunction. Supportive care is recommended as there is no specific antidote. (1)
Side effects
Side effects and their urgency vary; report severe, persistent, or concerning symptoms to a healthcare professional.
Nausea
Incidence: Reported in the clinician-authored database; frequency not established
Headache
Incidence: Reported in the clinician-authored database; frequency not established
Abdominal pain
Incidence: Reported in the clinician-authored database; frequency not established
Fatigue
Incidence: Reported in the clinician-authored database; frequency not established
Depression
Incidence: Reported in the clinician-authored database; frequency not established
Peripheral edema
Incidence: Reported in the clinician-authored database; frequency not established
Flatulence
Incidence: Reported in the clinician-authored database; frequency not established
Serious warnings
May cause liver injury — serious
Symptoms: May cause liver injury; monitor liver function regularly. Not recommended for use in children under 18 years. CORRECTED (FDA label): Xermelo is NOT RECOMMENDED at all in patients with moderate or severe hepatic impairment (Child-Pugh B or C) — this is stronger than a caution, because drug exposure rises 3.2- to 5.0-fold in these patients. May interact with other medications metabolized by CYP enzymes. Report any signs of serotonin syndrome or severe allergic reaction immediately. Xermelo can cause constipation, which can be serious — individual post-marketing and clinical-trial reports include intestinal perforation, obstruction, and fecaloma (a hardened mass of stool), particularly relevant because patients with metastatic carcinoid tumors may already have impaired gastrointestinal wall integrity. Report new or worsening constipation, or severe/persistent abdominal pain, to your healthcare provider promptly — the FDA label states Xermelo should be stopped if severe constipation or severe, persistent, or worsening abdominal pain develops, a decision made with the prescribing clinician.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (1)
Contraindications recorded in the clinician database — serious
Symptoms: Contraindications recorded in the clinician database: Contraindicated in patients with known hypersensitivity to telotristat ethyl or its components. Not recommended in moderate or severe hepatic impairment (see above). Monitor liver function tests regularly. Not recommended in pediatric patients. Use in pregnancy and lactation only if benefits outweigh risks.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (1)
Interactions
| Medicine or test | Effect | Action |
|---|---|---|
| Recorded interactions | Xermelo may interact with drugs that are substrates of CYP2B6, CYP2C19, CYP2D6, and CYP3A4 enzymes, potentially altering their effects. Caution is advised when co-administering with medications such as antidepressants, antipsychotics, or other serotonergic agents due to the risk of serotonin syndrome. Always inform your healthcare provider of all medications and supplements you are taking. | (1) |
Pregnancy, breastfeeding, kidney/liver function, age
Pregnancy
Available data on Xermelo use in pregnant women are insufficient to establish a drug-associated risk of major birth defects, miscarriage, or other adverse maternal or fetal outcomes. Use during pregnancy is a decision for the clinician managing the pregnancy, weighing the benefit of controlling carcinoid syndrome diarrhea against the limited safety data. (1)
Breastfeeding
There are no data on whether telotristat ethyl passes into human or animal breast milk, or its effects on a breastfed infant or on milk production. Because Xermelo can cause constipation in the person taking it, the FDA label advises monitoring a breastfed infant for symptoms of constipation if the mother is taking Xermelo — discuss with the clinician managing your or your baby's care. (1)
Children
Frequency: Not applicable. Weight Based: Not recommended for pediatric use. Max Daily Dose: Not applicable. Max Single Dose: Not applicable. Age Restrictions: Safety not established in children (1)
Renal_impairment
The FDA label states no dose change is needed for kidney impairment of any severity in people who are not on dialysis; there is no information on people with kidney failure requiring dialysis. Liver impairment is handled very differently: Xermelo is NOT recommended at all in people with moderate or severe liver impairment, because drug levels rise substantially (about 3 to 5 times higher) in those groups. People with mild liver impairment can take the usual dose but need closer monitoring for side effects such as constipation. Tell the prescribing clinician about any liver disease before starting Xermelo. (1)
Hepatic_impairment
The FDA label states no dose change is needed for kidney impairment of any severity in people who are not on dialysis; there is no information on people with kidney failure requiring dialysis. Liver impairment is handled very differently: Xermelo is NOT recommended at all in people with moderate or severe liver impairment, because drug levels rise substantially (about 3 to 5 times higher) in those groups. People with mild liver impairment can take the usual dose but need closer monitoring for side effects such as constipation. Tell the prescribing clinician about any liver disease before starting Xermelo. (1)
Monitoring
(1)Storage
Store at 25°C (77°F); excursions permitted between 15°C and 30°C (59-86°F). Keep each tablet in its package (blister) until you are ready to take it. Keep out of reach of children.
Professional information
Clinician-facing context only. This section does not replace current product labeling.
General
Indication: Carcinoid syndrome diarrhea
Dose summary: The recommended starting dose is 250 mg taken orally three times daily.
Renal context: The FDA label states no dosage adjustment is necessary in patients with mild, moderate, or severe renal impairment not requiring dialysis; there is no information on use in end-stage renal disease requiring dialysis (eGFR under 15 mL/min/1.73m²). Hepatic impairment is treated very differently: exposure to telotristat ethyl and its active metabolite telotristat increased 3.2-fold in moderate hepatic impairment (Child-Pugh B) and 5.0-fold in severe hepatic impairment (Child-Pugh C) versus normal liver function, so Xermelo is NOT recommended in patients with moderate or severe hepatic impairment. No dose adjustment is needed in mild hepatic impairment (Child-Pugh A), but additional monitoring for Xermelo-associated adverse reactions such as constipation is recommended in that group. (1)
Frequently asked questions
What is Xermelo used for?
Xermelo is used to reduce the frequency of diarrhea in adults with carcinoid syndrome who are already receiving somatostatin analog therapy.
How does Xermelo work?
Xermelo blocks the enzyme tryptophan hydroxylase, reducing serotonin production in the gut and helping control diarrhea caused by carcinoid syndrome.
Can Xermelo be used alone?
No, Xermelo is intended to be used in combination with somatostatin analog therapy, not as a standalone treatment.
What should I do if I miss a dose?
Take the missed dose as soon as you remember with food. If it is almost time for your next dose, skip the missed dose and continue your regular schedule. Do not take an extra dose to make up for it.
Are there any serious side effects I should watch for?
Yes, serious side effects include liver problems, severe allergic reactions, and serotonin syndrome. Contact your doctor immediately if you notice symptoms such as jaundice, swelling, or confusion.
Is Xermelo safe during pregnancy or breastfeeding?
There is limited data on the use of Xermelo during pregnancy or breastfeeding. Discuss the risks and benefits with your healthcare provider before use.
Can children take Xermelo?
Xermelo is not recommended for use in children under 18 years, as safety and effectiveness have not been established in this age group.
What happens if I take too much Xermelo?
Taking too much Xermelo can lead to an exacerbation of side effects such as nausea, abdominal pain, and fatigue. In cases of suspected overdose, it is crucial to seek immediate emergency medical attention. Contact your doctor or poison control center right away for guidance and treatment.
Can I drink alcohol while taking Xermelo?
It is generally advisable to limit or avoid alcohol consumption while taking Xermelo. Alcohol can potentially worsen gastrointestinal side effects, such as nausea and abdominal pain, which are already common with Xermelo. Discuss your alcohol intake with your healthcare provider for personalized advice.
Is Xermelo safe during pregnancy?
Xermelo's safety during pregnancy has not been definitively established. It is categorized as 'Consult doctor' regarding pregnancy. If you are pregnant, planning to become pregnant, or breastfeeding, it is essential to discuss the potential risks and benefits of Xermelo with your healthcare provider before starting or continuing treatment.
What is the mechanism of action of telotristat ethyl?
Telotristat ethyl, the active ingredient in Xermelo, is a prodrug that is converted to telotristat, a potent inhibitor of tryptophan hydroxylase. This enzyme is the rate-limiting step in serotonin biosynthesis. By inhibiting tryptophan hydroxylase, telotristat reduces peripheral serotonin production, which is implicated in the pathophysiology of carcinoid syndrome diarrhea. (1)
What is the generic name of Telotristat Ethyl?
The generic name is telotristat ethyl. It is sold under brand names including Teloxer, Telozest, Xermelo, Telotri.
What class of drug is telotristat ethyl?
Telotristat Ethyl is classed as: Tryptophan hydroxylase inhibitor (antidiarrheal for carcinoid syndrome).
References
- nullnull · null · accessed null · source 1
- Telotristat — patient drug information (MedlinePlus)U.S. National Library of Medicine (MedlinePlus) · US · accessed 2026-08-14 · source 2
- Xermelo — FDA approval record (Drugs@FDA NDA208794)U.S. Food and Drug Administration · US · accessed 2026-08-14 · source 3
- telotristat ethyl — RxNorm normalized drug concept (RXCUI 1872441)U.S. National Library of Medicine (RxNorm) · US · accessed 2026-08-14 · source 4
Brand names by country
Single-ingredient telotristat ethyl names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.
Priority countries
United States
- Xermelo250 mg · lexicon pharmaceuticals, inc.