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MYTESI

Generic: Crofelemer

Verified·Apr 23, 2026
Manufacturer
Napo
NDC
70564-802
RxCUI
1364454
Route
ORAL
ICD-10 indication
B20

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About MYTESI

What is this medication? Mytesi is a prescription medication specifically designed to treat non-infectious diarrhea in adults who are living with HIV or AIDS and are currently receiving antiretroviral therapy. It is the first botanical drug to be approved by the FDA for this purpose and is intended for the symptomatic relief of loose stools. It is important to note that this medicine is not used to treat diarrhea caused by infectious agents like bacteria, viruses, or parasites, and a doctor must confirm the diarrhea is non-infectious before treatment begins.

The active component of the drug is crofelemer, which is derived from the red bark sap of the Croton lechleri tree. It functions by targeting and regulating specific chloride channels located in the lining of the gastrointestinal tract. By controlling the amount of water and chloride secreted into the intestines, the medication helps to decrease the frequency of bowel movements and improve stool consistency without significantly impacting the transit time of waste through the digestive system.

Copay & patient assistance

  • Patient Copay Amount: As little as $0
  • Maximum Annual Benefit Limit: Not Publicly Available
  • Core Eligibility Restrictions: Must have commercial insurance; indicated for the symptomatic relief of non-infectious diarrhea in adult patients with HIV/AIDS who are on antiretroviral therapy (ART); subject to change or cancellation at any time.
  • RxBIN, PCN, and Group numbers: Not Publicly Available

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Prescribing information

From the FDA-approved label for MYTESI. Official source: DailyMed (NLM) · Label effective Dec 22, 2025

Indications and usage
1 INDICATIONS AND USAGE 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. ( 1 )
Dosage and administration
2 DOSAGE AND ADMINISTRATION 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 )
Contraindications
4 CONTRAINDICATIONS None. None ( 4 )
Warnings and precautions
5 WARNINGS AND PRECAUTIONS 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.
Drug interactions
7 DRUG INTERACTIONS 7.1 Nelfinavir, Zidovudine, and Lamivudine MYTESI administration did not have a clinically relevant interaction with nelfinavir, zidovudine, or lamivudine in a drug-drug interaction trial [see Clinical Pharmacology ( 12.3 )] .
Adverse reactions
6 ADVERSE REACTIONS 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 . Table 1: Common Adverse Reactions occurring in at least 2% of patients and at a higher incidence than placebo in HIV-Positive Patients in Three Placebo-Controlled Trials Adverse Reaction MYTESI 125 mg Twice Daily N = 229 n (%) Placebo N = 274 n (%) Upper respiratory tract infection 13 (6) 4 (2) Bronchitis 9 (4) 0 Cough 8 (4) 3 (1) Flatulence 7 (3) 3 (1) Increased bilirubin 7 (3) 3 (1) Nausea 6 (3) 4 (2) Back pain 6 (3) 4 (2) Arthralgia 6 (3) 0 Urinary tract infection 5 (2) 2 (1) Nasopharyngitis 5 (2) 2 (1) Musculoskeletal pain 5 (2) 1 (<1) Hemorrhoids 5 (2) 0 Giardiasis 5 (2) 0 Anxiety 5 (2) 1 (<1) Increased alanine aminotransferase 5 (2) 3 (1) Abdominal distension 5 (2) 1 (<) Less common adverse reactions that occurred in between 1% and 2% of patients taking 125 mg twice daily of MYTESI were abdominal pain, acne, increased aspartate aminotransferase, increased conjugated bilirubin, increased unconjugated blood bilirubin, constipation, depression, dermatitis, dizziness, dry mouth, dyspepsia, gastroenteritis, herpes zoster, nephrolithiasis, pain in extremity, pollakiuria, sinusitis and decreased white blood cell count.
Use in pregnancy
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. Data Animal Data Crofelemer was not teratogenic and did not produce embryofetal toxicity in pregnant rats following oral administration at doses up to 738 mg/kg/day during the period of organogenesis. The 738 mg/kg/day dose is 177 times the recommended daily human dose of 4.2 mg/kg/day. Crofelemer was not teratogenic in pregnant rabbits following oral administration at doses up to 400 mg/kg/day during the period of organogenesis. At a dose level of 400 mg/kg/day, which is 96 times the recommended daily human dose of 4.2 mg/kg/day, crofelemer produced an increase in fetal resorptions and abortions compared to controls. However, it is not clear whether these effects are related to the maternal toxicity (decreased body weight and decreased food consumption) observed.

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

Covered by plans

3%

162 of 5,509 plans

Most common tier

Tier 5

On 46% of covering formularies

Prior authorization required

62%

of covering formularies

TierFormularies on this tierShare
Tier 2 (generic)1
8%
Tier 4 (non-preferred brand)6
46%
Tier 5 (specialty)6
46%

Step therapy: 0% of formularies

Quantity limits: 23% of formularies

Coverage breadth: 13 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

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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.