Crofelemer

Crofelemer is an inhibitor of both the cyclic adenosine monophosphate (cAMP)-stimulated cystic fibrosis transmembrane conductance regulator (CFTR) chloride ion (Cl¯) channel, and the calcium-activated Cl¯ channels (CaCC) at the luminal membrane of enterocytes. The CFTR Cl¯ channel and CaCC regulate Cl¯ and fluid secretion by intestinal epithelial cells.

• MYTESI is indicated for symptomatic relief of non-infectious diarrhea in adult patients with HIV/AIDS on anti-retroviral therapy. MYTESI is an anti-diarrheal indicated for the symptomatic relief of non-infectious diarrhea in adult patients with HIV/AIDS on anti-retroviral therapy.ICD-10: B20

• None.contraindicated

Before starting MYTESI, rule out infectious etiologies of diarrhea [see Warnings and Precautions ( 5.1 )] . The recommended adult dosage of MYTESI is 125 mg taken orally two times a day, with or without food. Do not crush or chew MYTESI tablets. Swallow whole. Before starting MYTESI, rule out infectious etiologies of diarrhea. ( 2 , 5.1 ) The recommended adult dosage is 125 mg taken orally twice a day, with or without food. ( 2 ) Do not crush or chew the tablets. Swallow whole. ( 2 )

Risks of Treatment in Patients with Infectious Diarrhea : Consider infectious etiologies of diarrhea before starting treatment to reduce the risk of inappropriate therapy and worsening disease. ( 2 , 5.1 ) 5. 1 Risks of Treatment in Patients with Infectious Diarrhea Before starting MYTESI, rule out infectious etiologies of diarrhea. If infectious etiologies are not considered, and MYTESI is initiated based on a presumptive diagnosis of non-infectious diarrhea, then there is a risk that patients with infectious etiologies will not receive the appropriate treatments, and their disease may worsen. MYTESI is not indicated for the treatment of infectious diarrhea.

Most common adverse reactions (≥ 3%) are upper respiratory tract infection, bronchitis, cough, flatulence and increased bilirubin. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Napo Pharmaceuticals at 1-844-722-8256 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. A total of 696 HIV-positive patients in three placebo-controlled trials received MYTESI for a mean duration of 78 days. Of the total population across the three trials, 229 patients received a dosage of 125 mg twice a day for a mean duration of 141 days, and 171 patients received one of four higher than recommended dosages for a mean duration of 139 days (N=69) 14 days (N=102), 146 days (N=54), and 14 days (N=242), respectively. Adverse reactions in patients treated with MYTESI 125 mg twice daily that occurred in at least 2% of patients and at a higher incidence than placebo are provided in Table 1 .

Lactation : Women infected with HIV-1 should be instructed not to breastfeed due to the potential for HIV transmission. ( 8.2 ) 8.1 Pregnancy Risk Summary Crofelemer is minimally absorbed systemically by the oral route of administration and maternal use is not expected to result in fetal exposure to the drug [see Clinical Pharmacology ( 12.3 )] . In pregnant rats, no adverse fetal effects were observed with oral administration of crofelemer at doses up to 177 times the recommended clinical dose during the period of organogenesis. In pregnant rabbits, an increase in fetal resorptions and abortions compared to controls were observed with crofelemer at a dose of 96 times the recommended clinical dose. However, it is not clear whether these effects in rabbits are related to the maternal toxicity (decreased body weight and decreased food consumption) observed at this dose (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.

Metabolism

Absorption The absorption of crofelemer is minimal following oral dosing in healthy adults and HIV–positive patients and concentrations of crofelemer in plasma are below the level of quantitation (50 ng/mL). Therefore, standard pharmacokinetic parameters such as area under the curve, maximum concentration, and half-life cannot be estimated.

• Dec 31, 2012NDANDA202292Napo Pharms Inc

1. 1Off Label Use6227%
2. 2Drug Ineffective5122%
3. 3Product Dose Omission Issue2712%
4. 4Diarrhoea2611%
5. 5Death208.7%
6. 6Pain177.4%
7. 7Anxiety146.1%
8. 8Emotional Distress146.1%
9. 9Anhedonia125.2%
10. 10Fatigue114.8%
11. 11Chronic Kidney Disease104.4%
12. 12Dizziness104.4%
13. 13Constipation93.9%
14. 14Depression83.5%
15. 15Osteoporosis83.5%

The 10 most recently updated of 16 ClinicalTrials.gov registrations naming Crofelemer as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• Safety and Efficacy of Crofelemer in Adult Patients With Short Bowel Syndrome and Intestinal Failure (SBS-IF) Without Colon-in-continuity (CIC)
  Recruiting · Phase 2 · Interventional · 18 enrolled · Napo Therapeutics, S.p.A.
  NCT06904872updated 2026-06-09
• Ascending Doses of Crofelemer Powder for Oral Solution in Pediatric Microvillus Inclusion Disease (MVID)
  Active not recruiting · Phase 2 · Phase 3 · Interventional · 6 enrolled · Napo Pharmaceuticals, Inc.
  NCT06721871updated 2026-06-09
• Crofelemer for Functional Diarrhea
  Terminated · Phase 4 · Interventional · 17 enrolled · Beth Israel Deaconess Medical Center
  NCT04486326updated 2026-03-10
• Open-Label Pilot Study With Crofelemer in Patients With Short Bowel Syndrome
  Recruiting · Early phase 1 · Interventional · 6 enrolled · Lindsey Russell, MD
  NCT06326645updated 2026-02-12
• Yield of Diagnostic Tests and Effects of Crofelemer for Chronic Idiopathic Diarrhea In Non-HIV Patients
  Completed · Phase 4 · Interventional · 93 enrolled · The University of Texas Health Science Center, Houston
  NCT03898856updated 2026-02-12
• Incidence and Severity of Diarrhea in Patients With HER2 Positive Breast Cancer Treated With Trastuzumab and Neratinib
  Completed · Phase 2 · Interventional · 11 enrolled · University of California, San Francisco
  NCT03094052updated 2025-06-26
• Prophylaxis of Diarrhea in Adult Cancer Patients Receiving Targeted Cancer Therapy
  Completed · Phase 3 · Interventional · 287 enrolled · Napo Pharmaceuticals, Inc.
  NCT04538625updated 2024-07-26
• Diarrhea Prevention and Prophylaxis With Crofelemer in HER2 Positive Breast Cancer Patients
  Completed · Phase 2 · Interventional · 53 enrolled · Sandra Swain
  NCT02910219updated 2022-10-24
• Effects of Crofelemer on the Gut Microbiome in Healthy Volunteers and in HIV+ Patients With Non-Infectious Diarrhea
  Completed · Phase 4 · Interventional · 17 enrolled · Napo Pharmaceuticals, Inc.
  NCT04192487updated 2021-10-22
• Safety and Effectiveness of 3 Doses of Crofelemer Compared to Placebo in the Treatment of HIV Associated Diarrhea
  Completed · Phase 3 · Interventional · 374 enrolled · Bausch Health Americas, Inc.
  NCT00547898updated 2020-09-03

Frequently asked questions

How does Crofelemer work?

Crofelemer is an inhibitor of both the cyclic adenosine monophosphate (cAMP)-stimulated cystic fibrosis transmembrane conductance regulator (CFTR) chloride ion (Cl¯) channel, and the calcium-activated Cl¯ channels (CaCC) at the luminal membrane of enterocytes. The CFTR Cl¯ channel and CaCC regulate Cl¯ and fluid secretion by intestinal epithelial cells.

What is Crofelemer used for?

According to FDA labeling, Crofelemer carries indications including: MYTESI is indicated for symptomatic relief of non-infectious diarrhea in adult patients with HIV/AIDS on anti-retroviral therapy. MYTESI is an anti-diarrheal indicated for the symptomatic relief of non-infectious diarrhea in adult patients with HIV/AIDS on anti-retroviral therapy.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Crofelemer?

Crofelemer is classified as Other antidiarrheals, Antidiarrheal, Chloride Channel Antagonists.

What are the brand names for Crofelemer?

Crofelemer is marketed under brand names including Canalevia, Mytesi.

What are the contraindications for Crofelemer?

Crofelemer labeling lists contraindications including: None.. Always consult the full prescribing information and a clinician.