Skip to Content
Looking to save on your medications?  Find out how 


Generic name: crofelemer systemic

Brand names: Fulyzaq, Mytesi

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product

Tablet Delayed Release, Oral:

Fulyzaq: 125 mg [DSC] [contains methylparaben, propylparaben]

Mytesi: 125 mg [contains methylparaben, propylparaben]


Mechanism of Action

Inhibits cyclic adenosine monophosphate (cAMP)-stimulated cystic fibrosis transmembrane conductance regulator (CFTR) chloride ion channel and calcium activated chloride ion channels at the enterocyte luminal membrane. This regulates fluid secretion and water loss (high volume) due to diarrhea, normalizing chloride ion and water flow in the GI tract.



Minimal systemic absorption

Use: Labeled Indications

Diarrhea, HIV/AIDs-related (receiving antiretroviral therapy): Symptomatic relief of noninfectious diarrhea in patients with HIV/AIDS on antiretroviral therapy


There are no contraindications listed in the manufacturer's labeling.

Dosage and Administration

Dosing: Adult

Diarrhea, HIV/AIDs-related (receiving antiretroviral therapy): Oral: 125 mg twice daily. Note: Before starting treatment, rule out infectious etiologies of diarrhea.


Oral: May administer without regard to food. Swallow whole; do not crush or chew.


Store at 20°C to 25°C (68°F to 77°F); excursions permitted to 15°C to 30°C (59°F to 86°F).

Drug Interactions

There are no known significant interactions.

Adverse Reactions

1% to 10%:

Central nervous system: Anxiety (2%), depression (1% to 2%), dizziness (1% to 2%)

Dermatologic: Acne vulgaris (1% to 2%), dermatitis (1% to 2%)

Gastrointestinal: Flatulence (3%), nausea (3%), abdominal distention (2%), giardiasis (2%), hemorrhoids (2%), abdominal pain (1% to 2%), constipation (1% to 2%), dyspepsia (1% to 2%), gastroenteritis (1% to 2%), xerostomia (1% to 2%)

Genitourinary: Urinary tract infection (2%), pollakiuria (1% to 2%)

Hematologic & oncologic: Decreased white blood cell count (1% to 2%)

Hepatic: Increased serum bilirubin (3%), increased serum ALT (2%), increased direct serum bilirubin (1% to 2%), increased indirect serum bilirubin (1% to 2%), increased serum AST (1% to 2%)

Infection: Herpes zoster (1% to 2%)

Neuromuscular & skeletal: Arthralgia (3%), back pain (3%), musculoskeletal pain (2%), limb pain (1% to 2%)

Renal: Nephrolithiasis (1% to 2%)

Respiratory: Upper respiratory tract infection (6%), bronchitis (4%), cough (4%), nasopharyngitis (2%), sinusitis (1% to 2%)


Disease-related concerns:

  • HIV/AIDS: CD4 cell count and viral load do not have a clinical impact on crofelemer treatment; no adjustments are necessary based on CD4 cell count or viral load.
  • Infectious diarrhea: Crofelemer is not indicated for infectious diarrhea; there is a risk of inadequate or delayed treatment if used when infectious diarrhea is present. Rule out infectious causes for diarrhea prior to initiating treatment.


Pregnancy Risk Factor


Pregnancy Considerations

Adverse events were observed in some animal reproduction studies. Systemic absorption following oral administration is limited.

Patient Education

  • Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)
  • Patient may experience passing gas, cough, or common cold symptoms (HCAHPS).
  • Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.

Source: Wolters Kluwer Health. Last updated November 14, 2019.