Medicine guide

Xermelo

250 mg · Tablet

Prescription only
Tryptophan Hydroxylase Inhibitor

Active substance: Telotristat Ethyl
Made by: Lexicon Pharmaceuticals, Inc.
Source: Official label

Quoted from the official source. Not yet reviewed by Mediclarum — the leaflet in your pack is authoritative.

At a glance

Quoted from the official label · 2025-10-01

What it is

Tryptophan Hydroxylase Inhibitor

Used for

Xermelo is indicated for the treatment of carcinoid syndrome diarrhea in combination with somatostatin analog (SSA) therapy in

The label’s usual adult dose

The recommended dosage of Xermelo in adult patients is 250 mg three times daily for patients whose diarrhea is inadequately controlled by SSA therapy.

Full directions ↓

Do not take it if

None. None. ( 4 )

All warnings ↓

Good to know

Prescription only
FDA enforcement reports list no ongoing recall, and none from the last two years, for this product code · checked 2026-10-02

1other products contain Telotristat Ethyl — compare makers, forms and strengths

Every line above is selected, not written, from the official label. Nothing is reworded. DailyMed

What it is for

Xermelo is indicated for the treatment of carcinoid syndrome diarrhea in combination with somatostatin analog (SSA) therapy in
adults inadequately controlled by SSA therapy.
Xermelo is a tryptophan hydroxylase inhibitor indicated for the treatment of carcinoid syndrome diarrhea in combination with somatostatin analog (SSA) therapy in
adults inadequately controlled by SSA therapy.
( 1 )

From the official label · 2025-10-01 · DailyMed

How it works

From this product’s own US prescribing label.

Telotristat, the active metabolite of telotristat ethyl, is an inhibitor of tryptophan hydroxylase, which mediates the rate limiting step in serotonin biosynthesis.
The in vitro inhibitory potency of telotristat towards tryptophan hydroxylase is 29 times higher than that of telotristat ethyl.

Peak level after0.5–2 h

Half-life0.6 h

Mostly cleared after≈ 3 hfive half-lives — our arithmetic

How the body breaks it down

After a single oral dose of telotristat ethyl to healthy subjects, telotristat ethyl was absorbed and metabolized to its active metabolite, telotristat.

With food

Food Effect Administration of a single 500 mg dose of Xermelo (twice the recommended dose) with food resulted in higher exposure to both telotristat ethyl and telotristat.

Quoted from the prescribing label, sections “Mechanism of Action” and “Pharmacokinetics”. DailyMed · 2025-10-01

Do not take it if

None. None. ( 4 )

Quoted from the official label, section “Contraindications”.

How to take it

These directions are for this exact strength and form. Another one is different.

The recommended dosage of Xermelo in adult patients is 250 mg three times daily for patients whose diarrhea is inadequately controlled by SSA therapy.
Administration Take Xermelo with food [see Clinical Pharmacology ( 12.3 ), Clinical Studies ( 14 )] .
When short-acting octreotide is used in combination with Xermelo, administer short-acting octreotide at least 30 minutes after administering Xermelo [see Clinical Pharmacology ( 12.3 ), Clinical Studies ( 14 )] .
If a dose is missed, take the next dose at the regular time.
Do not take 2 doses at the same time to make up for a missed dose.
Discontinue Xermelo if severe constipation develops [see Warnings and Precautions ( 5.1 )].
The recommended dosage of Xermelo in adult patients is 250 mg three times daily for patients whose diarrhea is inadequately controlled by a SSA therapy.
( 2 ) Take Xermelo with food.
( 2 ) When short-acting octreotide is used in combination with Xermelo, administer short-acting octreotide at least 30 minutes after administering Xermelo.
( 2 , 7.1 ) Discontinue Xermelo if severe constipation develops.
( 2 , 5.1 )

Quoted from the official label, section “Dosage & Administration”.

Other warnings

Constipation:
Xermelo reduces bowel movement frequency; monitor patients for constipation and/or severe persistent or worsening abdominal pain.
Discontinue Xermelo if severe constipation or abdominal pain develops.
( 5.1 )
5.1 Constipation Xermelo reduces bowel movement frequency.
In a 12-week, placebo-controlled trial, in which patients had 4 or greater bowel movements per day, 2 out of 45 patients treated with a higher than recommended dosage of Xermelo reported constipation.
In one patient the constipation was serious, resulting in hospitalization.
During the 36-week extension period with higher than the recommended dosage, 10 of 115 patients reported constipation:
one developed intestinal perforation and one developed obstruction.
In another 12-week, placebo-controlled trial in which patients had less than 4 bowel movements per day, 4 out of 25 patients treated with the recommended dosage of Xermelo reported constipation.
Given that patients with metastatic carcinoid tumors may have impaired integrity of the gastrointestinal tract wall, monitor for the development of constipation and/or severe, persistent, or worsening abdominal pain in patients taking Xermelo.
Discontinue Xermelo if severe constipation or severe persistent or worsening abdominal pain develops [see Dosage and Administration ( 2 ), Adverse Reactions ( 6.1 )] .

Quoted from the official label, section “Warnings”.

Pregnancy and breastfeeding

Risk Summary There are no human data with Xermelo use in pregnant women to inform a drug-associated risk.
In animal reproduction studies, no effects on embryo-fetal development were observed with the administration of oral telotristat ethyl to rats during organogenesis at doses up to 750 mg/kg/day (approximately 9 times the exposure at the RHD [recommended human dose]).
Treatment of pregnant rabbits with oral telotristat ethyl during organogenesis produced maternal toxicity and post-implantation loss at doses of 250 mg/kg/day or higher (approximately 15 times the exposure at the RHD), and reduced fetal weight at 500 mg/kg/day (approximately 33 times the exposure at the RHD).
In a pre-/postnatal development study, an increased incidence of mortality in rat offspring was observed during postnatal days 0 to 4 at the maternal oral dose of 500 mg/kg/day (approximately 5 times the exposure at the RHD), given during organogenesis through lactation [see Data ] .
The estimated background risk of major birth defects and miscarriage for the indicated population is unknown.
All pregnancies have a background risk of birth defect, loss or other adverse outcomes.
In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.
Data Animal data An embryo-fetal development study performed in rats with oral telotristat ethyl at doses up to 750 mg/kg/day (approximately 9 times the AUC [area under the plasma concentration-time curve] for the active metabolite at the RHD) during organogenesis produced no harm to embryo-fetal development.
In pregnant rabbits treated orally with telotristat ethyl during organogenesis, an increased incidence of post-implantation loss at doses of 250 and 500 mg/kg/day (approximately 15 times the AUC for the active metabolite at RHD) and a decrease in fetal weight at 500 mg/kg/day (approximately 33 times the AUC for the active metabolite at the RHD) was observed.
The adverse effects on embryo-fetal development were associated with maternal toxicity (impaired weight gain and/or mortality) at 250 and 500 mg/kg/day.
No adverse effects on embryo-fetal development were observed at 125 mg/kg/day (approximately 5 times the AUC for the active metabolite at the RHD).
A pre-/postnatal development study was conducted in rats using oral administration of 100, 200, and 500 mg/kg/day telotristat ethyl during organogenesis through lactation.
An increased incidence of pup mortality was observed during postnatal days 0 to 4 at the maternal dose of 500 mg/kg/day (approximately 5 times the AUC for the active metabolite at the RHD).
No developmental abnormalities or effects on growth, learning and memory, or reproductive performance were observed through maturation of offspring at maternal doses of up to 500 mg/kg/day in surviving offspring.
IN SPECIFIC POPULATIONS
8.1 Pregnancy Risk Summary There are no human data with Xermelo use in pregnant women to inform a drug-associated risk.
In animal reproduction studies, no effects on embryo-fetal development were observed with the administration of oral telotristat ethyl to rats during organogenesis at doses up to 750 mg/kg/day (approximately 9 times the exposure at the RHD [recommended human dose]).
Treatment of pregnant rabbits with oral telotristat ethyl during organogenesis produced maternal toxicity and post-implantation loss at doses of 250 mg/kg/day or higher (approximately 15 times the exposure at the RHD), and reduced fetal weight at 500 mg/kg/day (approximately 33 times the exposure at the RHD).
In a pre-/postnatal development study, an increased incidence of mortality in rat offspring was observed during postnatal days 0 to 4 at the maternal oral dose of 500 mg/kg/day (approximately 5 times the exposure at the RHD), given during organogenesis through lactation [see Data ] .
The estimated background risk of major birth defects and miscarriage for the indicated population is unknown.
All pregnancies have a background risk of birth defect, loss or other adverse outcomes.
In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.
Data Animal data An embryo-fetal development study performed in rats with oral telotristat ethyl at doses up to 750 mg/kg/day (approximately 9 times the AUC [area under the plasma concentration-time curve] for the active metabolite at the RHD) during organogenesis produced no harm to embryo-fetal development.
In pregnant rabbits treated orally with telotristat ethyl during organogenesis, an increased incidence of post-implantation loss at doses of 250 and 500 mg/kg/day (approximately 15 times the AUC for the active metabolite at RHD) and a decrease in fetal weight at 500 mg/kg/day (approximately 33 times the AUC for the active metabolite at the RHD) was observed.
The adverse effects on embryo-fetal development were associated with maternal toxicity (impaired weight gain and/or mortality) at 250 and 500 mg/kg/day.
No adverse effects on embryo-fetal development were observed at 125 mg/kg/day (approximately 5 times the AUC for the active metabolite at the RHD).
A pre-/postnatal development study was conducted in rats using oral administration of 100, 200, and 500 mg/kg/day telotristat ethyl during organogenesis through lactation.
An increased incidence of pup mortality was observed during postnatal days 0 to 4 at the maternal dose of 500 mg/kg/day (approximately 5 times the AUC for the active metabolite at the RHD).
No developmental abnormalities or effects on growth, learning and memory, or reproductive performance were observed through maturation of offspring at maternal doses of up to 500 mg/kg/day in surviving offspring.
8.2 Lactation Risk Summary There are no data on the presence of telotristat ethyl in human or animal milk, the effects on the breastfed infant, or the effects on milk production.
The effects of local gastrointestinal and systemic exposure to telotristat ethyl on breastfed infants are unknown.
The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for Xermelo and any potential adverse effects on the breastfed infant from Xermelo or from the underlying maternal condition.
Clinical Considerations Monitor the breastfed infant for symptoms of constipation.
8.4 Pediatric Use The safety and effectiveness of Xermelo in pediatric patients have not been established.
8.5 Geriatric Use Of 45 patients in a clinical trial of Xermelo, 19 (42%) patients were 65 years of age and over.
No overall differences in safety or effectiveness were observed between these patients and younger patients, and other reported clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out.

Quoted from the official label, section “OTC — Pregnancy or Breast Feeding”.

Other medicines

CYP3A4 Substrates (e.g., midazolam):
Efficacy of concomitant drugs may be decreased; monitor for suboptimal efficacy and consider increasing the dose of the concomitant drug.
( 7.1 )
7.1 CYP3A4 Substrates Concomitant use of Xermelo may decrease the efficacy of drugs that are CYP3A4 substrates (e.g., midazolam) by decreasing their systemic exposure.
Monitor for suboptimal efficacy and consider increasing the dose for concomitant CYP3A4 substrates, if necessary [see Clinical Pharmacology ( 12.3 )] .
7.2 Short-Acting Octreotide Concurrent administration of short-acting octreotide with Xermelo significantly decreased the systemic exposure of telotristat ethyl and telotristat, the active metabolite.
If treatment with short-acting octreotide is needed in combination with Xermelo, administer short-acting octreotide at least 30 minutes after administration of Xermelo [see Clinical Pharmacology ( 12.3 ), Clinical Studies ( 14 )] .

Quoted from the official label, section “Drug Interactions”.

Use in children

The safety and effectiveness of Xermelo in pediatric patients have not been established.

Quoted from the official label, section “Pediatric Use”.

Use in older people

Of 45 patients in a clinical trial of Xermelo, 19 (42%) patients were 65 years of age and over.
No overall differences in safety or effectiveness were observed between these patients and younger patients, and other reported clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out.

Quoted from the official label, section “Geriatric Use”.

Side effects

Most common adverse reactions (≥5%) are nausea, headache, increased GGT, depression, flatulence, decreased appetite, peripheral edema, and pyrexia.
( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact TerSera Therapeutics LLC at 1-844-334-4035 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch
6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
Xermelo was studied in a double-blind, placebo-controlled clinical trial of 90 patients with metastatic neuroendocrine tumors and carcinoid syndrome diarrhea.
Patients reported between 4 to 12 bowel movements daily despite the use of SSA therapy at a stable dose for at least 3 months [see Clinical Studies ( 14 )] .
Placebo or Xermelo 250 mg was administered three times daily for 12 weeks.
Concomitant anti-diarrheal medications (e.g., loperamide) were used by 43% (36% and 51% in the placebo and Xermelo group, respectively), pancreatic enzyme replacement medications by 39% (36% and 42% in the placebo and Xermelo group, respectively), and opioid analgesics by 29% (24% and 33% in the placebo and Xermelo group, respectively) of patients during the 12-week double-blind period of the trial.
Table 1 below lists adverse reactions occurring at an incidence of at least 5% in the Xermelo group (N=45) and at an incidence greater than placebo (N=45) during the 12-week placebo-controlled period of the trial.
Table 1:
Percent Common Adverse Reactions a by Treatment Group at 12-Weeks in a Double-Blind Placebo-Controlled Clinical Trial of Patients with Carcinoid Syndrome Diarrhea a incidence of at least 5% in the Xermelo group and at an incidence greater than placebo b including depression, depressed mood and decreased interest Adverse Reaction Xermelo 250 mg Three Times Daily, N=45 (%) Placebo, N=45 (%) Nausea 13 11 Headache 11 4 Increased gamma-glutamyl-transferase (GGT) 9 0 Depression b 9 7 Peripheral edema 7 2 Flatulence 7 2 Decreased appetite 7 4 Pyrexia 7 4 In another placebo-controlled clinical trial of patients with carcinoid syndrome diarrhea and less than 4 bowel movements per day, the following additional adverse reactions, not listed in Table 1 , of abdominal pain (including upper and lower abdominal pain, abdominal distention and gastrointestinal pain) and constipation were reported in at least 5% of patients in the Xermelo treated group and at an incidence greater than placebo [see Warnings and Precautions ( 5.1 )] .
Less Common Adverse Reactions :
The following is a list of adverse reactions occurring in less than 5% of patients receiving Xermelo during the 12-week placebo-controlled period of the clinical trial:
Investigations :
increased alkaline phosphatase, increased alanine aminotransferase, and increased aspartate aminotransferase.
Fecaloma was reported in one patient treated with Xermelo during the 36-week open-label extension period following the 12-week double-blind period of the trial.

Quoted from the official label, section “Adverse Reactions”.

What to discuss with your doctor

Advise patients:
If they experience severe constipation or severe persistent or worsening abdominal pain, to discontinue Xermelo and contact their healthcare provider [see Warnings and Precautions ( 5.1 )] .
To take Xermelo with food [see Clinical Pharmacology ( 12.3 ), Clinical Studies ( 14 )] .
When short-acting octreotide is used in combination with Xermelo, administer short-acting octreotide at least 30 minutes after administering Xermelo [see Clinical Pharmacology ( 12.3 ), Clinical Studies ( 14 )] .
If a dose is missed, take the next dose at the regular time.
Do not take 2 doses at the same time to make up for a missed dose.
Distributed by: Lexicon Pharmaceuticals, Inc.
The Woodlands, TX 77381

Quoted from the official label, section “Patient Counseling Information”.

Strengths and forms

FORMS AND STRENGTHS Tablets:
250 mg telotristat ethyl; white to off-white, coated and oval with “T-E” debossed on one side and “250” debossed on the other side. Tablets:
250 mg telotristat ethyl ( 3 )

Quoted from the official label, section “Dosage Forms & Strengths”.

What it looks like and how it is packed

How Supplied 250 mg tablet:
white to off-white coated oval tablet with “T-E” debossed on one side and “250” debossed on the other side.
Xermelo is dispensed in a monthly case for a total of 28 days of therapy.
Each monthly case contains four weekly packs.
Each weekly pack contains 21 tablets.
NDC 70183-125-85: Monthly case of 84 tablets.
Each child resistant weekly pack contains twenty one 250 mg tablets.
Storage
Store at 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 86°F) [see USP Controlled Room Temperature].

Quoted from the official label, section “How Supplied”.

How to store it

Store at 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 86°F) [see USP Controlled Room Temperature].

Quoted from the official label, section “Storage and Handling”.

What is in it

Xermelo (telotristat ethyl) tablets contain telotristat ethyl as telotristat etiprate, a tryptophan hydroxylase inhibitor. Telotristat etiprate is the hippurate salt of telotristat ethyl [(S)-ethyl 2-amino-3-(4-(2-amino-6-((R)-1-(4-chloro-2-(3-methyl-1H-pyrazol-1-yl)phenyl)-2,2,2-trifluoroethoxy)pyrimidin-4-yl)phenyl)propanoate], which undergoes hydrolysis to the active metabolite, (S)-2-amino-3-(4-(2-amino-6-((R)-1-(4-chloro-2-(3-methyl-1H-pyrazol-1-yl)phenyl)-2,2,2-trifluoroethoxy)pyrimidin-4-yl)phenyl)propanoic acid. The molecular formula of telotristat etiprate is C 27 H 26 ClF 3 N 6 O 3
C 9 H 9 NO 3 and its molecular weight is 754.2. The molecular weight of the free base (telotristat ethyl) is 575.0. Chemical Structure:
Telotristat etiprate is a white to off-white solid. The solubility is a function of pH at 25°C; at pH 1 (0.1N HCl), the solubility is greater than 71 mg/mL, at pH 3 phosphate buffer, the solubility is 0.30 mg/mL, at a pH of 5 to 9, the solubility is negligible. In organic solvents, telotristat etiprate is freely soluble in methanol, soluble in acetone, and sparingly soluble in ethanol. Each Xermelo tablet contains 250 mg of telotristat ethyl (free base) which is equivalent to 328 mg telotristat etiprate. The inactive ingredients of Xermelo tablets include:
colloidal silicon dioxide, croscarmellose sodium, hydroxypropyl cellulose, lactose anhydrous, macrogol/PEG, magnesium stearate, polyvinyl alcohol [part hydrolyzed], talc and titanium dioxide. Chemical Structure

Quoted from the official label, section “Description”.

Ingredients people check for

Lactose, gluten, dyes, sugars and other ingredients that matter with an allergy, intolerance or diet — as this product’s FDA label lists them.

Lactoselactose anhydrousMilk sugar: matters with lactose intolerance or a milk allergy.
Titanium dioxidetitanium dioxideA whitening agent no longer allowed in food in the EU (E171).

Quoted from the FDA label. A label that does not name an ingredient is not a guarantee that the product is free of it, and formulations change. With an allergy, check the pack and ask a pharmacist.

Every version of this medicine (2)

The same active substance, strength and kind of form, from every company that sells it — with what each label lists.

Showing 2 of 2

Same active substance, strength and form in other countries

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Medicine passport: one printable page to show a pharmacist abroad

European UnionNo exact match for this strength and form

Every strength and form (1)

Details

Made by	Lexicon Pharmaceuticals, Inc.
Active substance	Telotristat Ethyl
Strength	250 mg
Form	Tablet
Route	Oral
NDC	70183-125

Source: NDC Directory · 2026-09-13 · not reviewed by a clinician

Source: US Food and Drug Administration, NDC Directory. Reuse terms: US government work (FDA).

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Other strengths and forms

2 products are sold under this name. Grouped by form; a number on a strength means several companies make it.

Tablet2 products
- 250 mg2
  250 mg · 2 companies
  - Lexicon Pharmaceuticals, Inc. · this page
  - TerSera Therapeutics LLC

Same active substance

These contain the same substance. That does not mean one can replace another — ask a pharmacist.

Xermelo250 mgPrescription onlyTablet TerSera Therapeutics LLC · Telotristat Ethyl

See every product with Telotristat Ethyl