Treating HIV-Associated Diarrhea with Fulyzaq

First FDA Approved Drug for Treating Severe Diarrhea in People with HIV

Photograph courtesy Salix Pharmaceuticals


Fulyzaq (crofelemer) is drug whose active ingredient is derived from the purified resin of the South American Croton lechleri tree, which is used to treat non-infectious, diarrhea in people with HIV on antiretroviral therapy. It was granted approval by the U.S. Food and Drug Administration (FDA) on December 31, 2012.

Fulyzaq is approved specifically to treat diarrhea caused by HIV drugs, although it can relieve the symptoms of infectious diarrhea (gastroenteritis) or diarrhea caused by irritable bowel syndrome.

Fulyzaq is neither a treatment for HIV/AIDS nor does it treat any infection that may have caused the diarrhea.

Fulyzaq is only the second botanical drug approved by the FDA in accordance with the same extensive human clinical trials required of all prescription drugs. The other is the drug Veregen (sinecatechins) used for the treatment of genital and perianal warts.

Clinical Research Highlights

A randomized, double-blind Phase III trial concluded that participants taking Fulyzaq were more than twice as likely to achieve positive clinical response, with far fewer watery stools and better stool consistency, than the participants in the placebo group. Furthermore, the drug was shown to have minimal side effect, was well tolerated, and did not impact the patient's CD4 count or viral load.

Fulyzaq works by blocking the secretion of chloride ions in intestinal cells and, in doing so, reduces the incidence of watery stools by normalizing the water in the gastrointestinal tract.

Dosage and Drug Administration

Fulyzaq is available as a white, oval, enteric-coated tablet printed on one side with "125SLXP." The recommended adult dose is two 125mg tablets taken orally per day, with or without food. As Fulyzaq is formulated as a delayed-release drug, it should not be chewed or crushed, but swallowed whole.

Fulyzaq can be stored at room temperature.

No overdosages have been reported in patients taking Fulyzaq.

Common Side Effects

Based on clinical research, the most common side effects (occurring in 3% or less of patients) are:

  • Upper respiratory infection
  • Bronchitis
  • Cough
  • Flatulence
  • Raised bilirubins

Other possible symptoms include body aches, chills, ear congestion, headache, fever, runny nose, sneezing, tiredness.

Drug Interactions or Incompatibility

No significant drug interactions were reported.


There is currently no clinical research into the effect of Fulyzaq during pregnancy, either on the impairment of fertility or possible harm to the fetus. It is also not known if Fulyzsaq can be excreted in breast milk during nursing. As such, Fulyzaq should only be used during pregnancy if clearly indicated and ideally with input from the patient’s OB/GYN specialist.

Similarly, as the safety and effectiveness of Fulyzaq has not been established in children under the age of 18, it is recommended that the drug be used with caution.


U.S. Food and Drug Administration (FDA).  "FDA approves first anti-diarrheal drug for HIV/AIDS patients." Silver Spring, Maryland; press release issued December 31, 2012.

MacArthur, R.; Hawkins, T.; Brown, S.; et al. "Efficacy and safety of crofelemer for noninfectious diarrhea in HIV-seropositive individuals (ADVENT trial): a randomized, double-blind, placebo-controlled, two-stage study." HIV Clinical Trials. November-December 2013; 14(6): 261-273.52nd Interscience Conference on Antimicrobial Agents and Chemotherapy. San Francisco; September 9-12, 2012; Abstract H-556b.

Salix Pharmaceuticals, Inc. "Fulzaq [prescribing information]." Raleigh, North Carolina; accessed August 25, 2014.

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