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Xermelo

Generic: telotristat ethyl

Verified·Apr 23, 2026
Manufacturer
Lexicon
NDC
70183-125
RxCUI
1872453
Route
ORAL
ICD-10 indication
E34.0

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About Xermelo

What is this medication?

Xermelo is a prescription medicine used to treat carcinoid syndrome diarrhea in adults. It is specifically intended for patients whose symptoms are not adequately controlled by somatostatin analog therapy, such as octreotide or lanreotide. This medication is taken orally and is used in combination with those existing therapies to help reduce the frequency of bowel movements.

The active ingredient in Xermelo is telotristat ethyl, which functions as a tryptophan hydroxylase inhibitor. It works by reducing the production of serotonin, a chemical that is often overproduced by certain types of tumors in people with carcinoid syndrome. By lowering the levels of serotonin in the body, Xermelo helps to decrease the severity of chronic diarrhea associated with this condition.

Copay & patient assistance

  • Patient Copay Amount: As little as $0
  • Maximum Annual Benefit Limit: Not Publicly Available (Note: Subject to an annual limit, but specific dollar amount is not listed)
  • Core Eligibility Restrictions: Available only to commercially insured patients. Not eligible for patients whose prescriptions are paid in whole or in part by any state or federally funded program, including Medicare, Medicaid, Medigap, VA, DOD, TRICARE, or where prohibited by law.
  • RxBIN, PCN, and Group numbers: Not Publicly Available

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Prescribing information

From the FDA-approved label for Xermelo. Official source: DailyMed (NLM) · Label effective Oct 1, 2025

Indications and usage
1 INDICATIONS AND USAGE 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 )
Dosage and administration
2 DOSAGE AND ADMINISTRATION 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 )
Contraindications
4 CONTRAINDICATIONS None. None. ( 4 )
Warnings and precautions
5 WARNINGS AND PRECAUTIONS 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 )] .
Drug interactions
7 DRUG INTERACTIONS 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 )] .
Adverse reactions
6 ADVERSE REACTIONS 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 Lexicon Pharmaceuticals, Inc. at 1-844-539-7427 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.
Use in pregnancy
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.

Label text is reproduced as-is from the FDA-approved label. We do not paraphrase, summarize, or omit. Content above is for informational purposes only and is not medical advice. Always consult your prescribing clinician or pharmacist before making decisions about your medication.

Conditions we've indexed resources for

Click a condition to see copay cards, grants, and PA rules specific to it. For the full list of FDA-approved indications, see Prescribing information above.

Medicare Part D coverage

How Xermelo appears across Medicare Part D plan formularies nationally. Source: CMS monthly Prescription Drug Plan file (2026-04-30).

Covered by plans

76%

4,178 of 5,509 plans

Most common tier

Tier 5

On 79% of covering formularies

Prior authorization required

99%

of covering formularies

TierFormularies on this tierShare
Tier 1 (preferred generic)59
18%
Tier 2 (generic)2
1%
Tier 4 (non-preferred brand)7
2%
Tier 5 (specialty)260
79%
Tier 61
0%

Step therapy: 0% of formularies

Quantity limits: 95% of formularies

Coverage breadth: 329 of 65 formularies

How to read this:plans on the same formulary share tier + PA rules. Your specific plan's copay depends on (a) the tier above, (b) your plan's cost-share for that tier, (c) whether you're in the initial coverage phase or past the 2026 $2,000 out-of-pocket cap. For your exact plan, check its Summary of Benefits or log in to your Medicare.gov account. Copay cards don't apply to Medicare (federal law).

Prior authorization & coverage

PayerPAStep therapyCopay tier

Medicare Part D

Related drugs

How this page is sourced

  • Drug identity verified against openFDA NDC Directory.
  • Label text (when shown) originates from NLM DailyMed.
  • Copay and assistance URLs verified periodically; if you hit a broken link, tell us.

Rare-disease navigation (specialists, trials, patient communities)

Xermelo treats a rare condition. For in-depth disease pages on our sister site:

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