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Telotristat ethyl

Pronunciation: tel-OH-tri-stat-ETH-il
Brand name: Xermelo
Dosage form: tablet (250mg)
Drug class: Miscellaneous GI agents

Medically reviewed by Melisa Puckey, BPharm. Last updated on Feb 11, 2025.

What is Telotristat ethyl?

Telotristat ethyl is an FDA-approved medication used to treat carcinoid syndrome diarrhea in combination with somatostatin analog (SSA) therapy when SSA therapy alone does not provide adequate relief.  Carcinoid syndrome diarrhea is due to carcinoid tumors producing excess serotonin which causes frequent diarrhea and other symptoms.

Telotristat ethyl works by blocking the enzyme responsible for producing serotonin, thereby reducing serotonin levels in the body. This reduction helps control diarrhea associated with carcinoid syndrome.

Telotristat ethyl brand name is Xermelo.

Telotristat ethyl FDA approval indication is for the treatment of carcinoid syndrome diarrhea in combination with SSA therapy for adults whose symptoms remain uncontrolled by SSA therapy alone. FDA approval was granted on February 28, 2017, for Lexicon Pharmaceuticals, Inc.

How telotristat ethyl works

Telotristat ethyl mechanism of action is as a tryptophan hydroxylase inhibitor

This medication is not a chemotherapy drug and does not treat the tumor itself. Instead, it manages symptoms associated with carcinoid syndrome.

Clinical trials: How effective is telotristat ethyl?

Phase III Study Results

A placebo-controlled phase III study (TELESTAR) evaluated telotristat ethyl in 135 carcinoid syndrome patients who experienced 4 or more bowel movements (BM) per day despite taking somatostatin analog therapy. Telotristat dose was three times daily.

Key Findings (12-Week Double-Blind Study):

Conclusion: The study demonstrated that telotristat ethyl effectively reduces diarrhea symptoms in patients with carcinoid syndrome, when SSAs alone are insufficient.

Telotristat ethyl side effects

Common telotristat side effects:

These common side effects occurred in at least 5% of patients taking Telotristat 250 mg three times a day in the double-blind, placebo-controlled clinical trial of 90 patients with metastatic neuroendocrine tumors and carcinoid syndrome diarrhea.

Serious telotristat side effects

This is not a comprehensive list of side effects. Consult your doctor for medical advice, or report side effects to the FDA at 1-800-FDA-1088.

Warnings 

Before taking this medicine

Tell your doctor if you have:

This medication is not approved for individuals under 18 years old.

Telotristat ethyl dosage

Recommended telotristat ethyl adult dose

Missed Dose

Overdose

Drug interactions

Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective.

You can use the Drug Interaction Checker or consult your healthcare provider to verify potential interactions.

Does telotristat interact with my other drugs?

Enter medications to view a detailed interaction report using our Drug Interaction Checker.

Telotristat Ethyl Package Insert 

HCPs and patients often use the Telotristat Ethyl Package Insert (PI) - Xermelo brand - for more detailed information about this medicine. The Telotristat Ethyl Package Insert (prescribing information) contains more comprehensive information on Indications and Usage, Dosage and Administration, Clinical Pharmacology, Clinical Studies, Drug Interaction, and more. Discuss any medical questions you have with your HCP (health care professional). This is not all the information you need to know about this medicine for safe and effective use, and it does not take the place of talking to your doctor about your treatment.

The Package Insert is sometimes called Prescribing Information (PI) or FDA label.

Additional information

Storage

Ingredients

Manufacturer

Telotristat ethyl is produced by Lexicon Pharmaceuticals, Inc., located in The Woodlands, TX 77381.

Popular FAQ

How long does it take for Xermelo to start working?

In studies conducted for the FDA approval of Xermelo, most patients saw a significant improvement in their diarrhea frequency in 12 weeks, and some patients saw results as soon as 3 weeks. Xermelo targets the overproduction of serotonin inside mNET cells to lessen carcinoid syndrome diarrhea.

What type of diarrhea does Xermelo treat?

Xermelo (telotristat ethyl) is a tablet used to treat carcinoid syndrome diarrhea. This is a type of diarrhea that develops in people with carcinoid tumors. Continue reading

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.