Crofelemer
Crofelemer is an anti-diarrheal medicine used to relieve non-infectious diarrhea in adults with HIV/AIDS who are on antiretroviral therapy.
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 1 clinical label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
📖 Crofelemer: Patient Information Guide
A plain-language walkthrough of Crofelemer — what it treats, how it works, how it’s taken, side effects, warnings and interactions. Tap any section to expand it.
🎯What it's used for▾
Crofelemer is approved for one specific use, tied to the brand Mytesi:
- Mytesi (oral tablet): Symptomatic relief of non-infectious diarrhea in adults with HIV/AIDS who are on antiretroviral therapy.
⚙️How it works▾
Crofelemer blocks two types of chloride ion channels — the CFTR channel and the calcium-activated chloride channel (CaCC) — on the surface of intestinal cells. These channels normally regulate how much chloride and water move into the gut. When they are overactive, large amounts of fluid pour into the intestine, causing watery diarrhea. By blocking these channels, crofelemer reduces that excess fluid secretion and normalizes stool consistency.
Importantly, crofelemer is barely absorbed into the bloodstream after swallowing — it acts almost entirely within the gut itself. This means it does not significantly affect the rest of the body or most other medications you may be taking.
💊How it's taken▾
Mytesi is taken as an oral tablet twice a day. It can be taken with or without food, so you can fit it into your routine however works best for you.
- Swallow the tablet whole — never crush or chew it.
- Follow your prescriber's schedule exactly.
- No specific dose adjustments are recommended based on CD4 cell count or HIV viral load.
🤒Side effects — in detail▾
The most commonly reported side effects with Mytesi (occurring in at least 2% of patients in clinical trials) include:
- Upper respiratory tract infection (cold-like symptoms)
- Bronchitis (inflammation of the airways)
- Cough
- Flatulence (gas)
- Increased bilirubin (a liver-related marker in the blood)
- Nausea
- Back pain
- Joint pain (arthralgia)
- Urinary tract infection
- Nasopharyngitis (inflammation of the nose and throat)
Contact your doctor if diarrhea worsens or does not improve, or if you notice any new or concerning symptoms after starting this medicine.
⚠️Warnings & precautions▾
- Do not use for infectious diarrhea: Mytesi is only for diarrhea that is not caused by an infection. Your doctor must rule out infectious causes first. Using Mytesi when an infection is present could delay proper treatment and make the infection worse.
- Pediatric use: Safety and effectiveness in children have not been established — Mytesi is approved for adults only.
- Older adults: There is limited data on patients aged 65 and over; discuss any concerns with your prescriber.
🔀What it interacts with▾
Because crofelemer is minimally absorbed into the bloodstream, it has a low potential for systemic drug interactions. Studies have looked at a few specific combinations:
- Nelfinavir and zidovudine (HIV medications): No clinically meaningful interaction was found with Mytesi.
- Lamivudine (HIV medication): A small decrease in lamivudine exposure was seen in studies, but it was not considered clinically important.
- Gut-level enzyme effects: Crofelemer may affect certain transporters in the intestine, but due to its minimal absorption, it is unlikely to interact with most drugs processed by the liver.
This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.
📋Before taking it▾
- Infectious diarrhea must be ruled out by your doctor before you start Mytesi — using it for the wrong type of diarrhea can cause harm.
- Pregnancy: Crofelemer is minimally absorbed, so exposure to the fetus is not expected. Still, tell your doctor if you are pregnant or planning to become pregnant.
- Breastfeeding: Women with HIV should not breastfeed regardless of medication use, to avoid transmitting HIV to the baby. Do not breastfeed while taking Mytesi.
- Children: Not approved for pediatric patients — safety and effectiveness are not established.
- Older adults (65+): Limited clinical data are available for this age group; your prescriber will weigh the risks and benefits.
- Low CD4 counts or high viral loads: No dose changes are needed based on these values, and the safety profile appeared similar regardless of CD4 count or viral load in clinical studies.
📡Pharmacodynamics — effects in the body▾
In clinical studies, crofelemer reduced stool chloride concentrations compared to placebo — consistent with its action of blocking chloride secretion in the gut. At a dose ten times the maximum recommended amount, crofelemer did not cause any clinically meaningful prolongation of the QTc interval (an electrical measurement of heart rhythm), suggesting it does not pose a significant cardiac risk at therapeutic doses.
🔬Pharmacokinetics — how your body processes it▾
Crofelemer is very poorly absorbed after swallowing — blood concentrations remain below measurable levels in both healthy adults and people with HIV. Because so little enters the bloodstream, standard measurements like half-life and peak concentration cannot be calculated. Food (including a high-fat meal) does not meaningfully increase systemic absorption. This minimal absorption also means crofelemer is unlikely to interact with liver enzymes that process most other medications.
📦How to store it▾
Store at 20°C-25°C (68°F-77°F); excursions permitted between 15°C-30°C (59°F-86°F).
📄 Written from Crofelemer’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Every point is grounded in that labeling — nothing is invented. How we use AI →
Supplements & herbs that interact with Crofelemer
17 supplements and herbal products have documented interactions with Crofelemer in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.
- Major · 1
- Moderate · 7
- Minor · 9
Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.
🩺 Pharmacist Counseling Corner
Quick, plain-English answers to the questions patients ask most about Crofelemer — the kind of thing our pharmacy team would talk through with you at the counter.
What exactly is Mytesi for — can I take it for any stomach bug? ▾
Will this medicine interfere with my HIV medications? ▾
How do I take this tablet — does it matter if I have food? ▾
What side effects should I expect, and when should I call my doctor? ▾
Can I take this if I'm pregnant or breastfeeding? ▾
Is this medicine safe for my child or teenager with HIV? ▾
Is Crofelemer available over the counter? ▾
When was Crofelemer first available? ▾
Who makes Crofelemer? ▾
💬 Answers drafted from Crofelemer’s FDA-approved label information, summarized in plain language with AI, and reviewed by our pharmacy team before publication. Grounded in that labeling — nothing is made up. How we use AI →
🧰 Keep exploring
💊 How Crofelemer comes
Crofelemer is available in 1 form. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Tablet
How this form is used
- Mytesi tablets are used to relieve non-infectious diarrhea in adults with HIV/AIDS who are on antiretroviral therapy.
- Mytesi tablets are taken by mouth twice a day.
- Mytesi can be taken with or without food.
- Swallow Mytesi tablets whole — do not crush or chew them.
- Before starting Mytesi, your doctor should confirm your diarrhea is not caused by an infection.
📊 Crofelemer across the U.S. market
How Crofelemer appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
Also listed with the FDA, not a patient dose form: Powder (1) — bulk drug substance sold to compounders/manufacturers and multi-item kits. These aren’t counted in the dose-form total above.
Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.
📈 How widely Crofelemer is used
A general measure of how commonly Crofelemer is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.
Think of this as a proxy for how widely Crofelemer is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.
How commonly is Crofelemer prescribed? Of the 1,596 medications we measure, Crofelemer ranks #1,418 by Medicaid prescriptions — more than 11% of them.
Utilization by Crofelemer product
Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.
crofelemer 125 MG Delayed Release Oral Tablet
Summed across the 1 of 1 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1364454
Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.
Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Crofelemer, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 1 of 1 listed Crofelemer NDCs with Medicaid activity.
🔍 Compare Crofelemer products
A representative set of FDA-listed product records for Crofelemer — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Tablet | ||||
| 125 mg | Oral | Napo Pharmaceuticals, Inc. × 3 listings | NDA | View NDC → |
| 💊Bulk drug substance | ||||
| 1 g/g | — | Indena SpA | BULK INGREDIENT | View NDC → |
Showing 4 of 4 products — FDA National Drug Code Directory. See every product, package size and price: browse all 4 Crofelemer NDCs →
📈 What people report — real-world data (FDA FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Crofelemer — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Crofelemer in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
🏛️ The road to your pharmacy
How Crofelemer went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
🚨 Recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
Source: openFDA drug enforcement (recall) reports.
RxNorm Concept Web — From Ingredient to Every Form and Strength
This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.
RxCUI 1364449 1 dose form · 1 strength
-
Dose form (SCDF) Delayed Release Oral Tablet RxCUI 1364453No current FDA listingClinical drug / strength (SCD) 125 MGRxCUI 1364454
Look up RxCUI 1364449 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
📦 Supply & shortage status
Whether Crofelemer is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
🏷️ Sold under these brand names
🏭 Manufacturers & labelers
RxNorm drug class
Crofelemer belongs to the Antidiarrheal class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
🔬 Where this comes from
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How we combine label and product data
HelloPharmacist combines public FDA and NLM records; we don’t author the underlying clinical facts. We identified 1 FDA-filed SPL label set within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. The representative label is the starting point for the displayed reference monograph; the 12 largest stored in-scope SPL records, which may include that representative, are compared section by section, and the longest available version of each section is retained. Forms, routes, brands, labelers, product-listed strengths, and product-record counts are aggregated separately from ingredient-matched FDA NDC Directory records; package records listed above are associated with the linked SPL; and the normalized concept hierarchy comes from NLM RxNorm.
For canonical ingredient pages, bounded product-attributed indication and administration excerpts may be added to the AI evidence, and the generator is instructed to preserve available product, brand, route, and form qualifiers instead of treating one label as universal. Where a section is identified as AI-written, its plain-language text is generated from bounded label evidence. New draft drug pages remain in the admin review queue before first publication. Napo Pharmaceuticals, Inc. is the representative DailyMed label linked for verification and dates; it is not the sole source used for the page.
This is general education, not medical advice — always consult your doctor or pharmacist about your medications and any medical condition. For the exact wording of the linked representative label, view that label on DailyMed; some displayed composite sections may come from other in-scope SPL labels. Learn how we use AI and our data sources & update cadence.