Adverse reactions that occurred in between 1% and 2% of patients taking a 250 mg daily dose of FULYZAQ 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, procedural pain, seasonal allergy, sinusitis and decreased white blood cell count.
Adverse reactions were similar in patients who received doses greater than 250 mg daily.
Drug Interactions
7.1 Drug Interaction Potential
In vitro studies have shown that crofelemer has the potential to inhibit cytochrome P450 isoenzyme 3A and transporters MRP2 and OATP1A2 at concentrations expected in the gut. Due to the minimal absorption of crofelemer, it is unlikely to inhibit cytochrome P450 isoenzymes 1A2, 2A6, 2B6, 2C9, 2C19, 2D6, 2E1 and CYP3A4 systemically [see Clinical Pharmacology (12.3)].
7.2 Nelfinavir, Zidovudine, and Lamivudine
FULYZAQ administration did not have a clinically relevant interaction with nelfinavir, zidovudine, or lamivudine in a drug-drug interaction trial.
USE IN SPECIFIC POPULATIONS
Pregnancy
Pregnancy Category C
Reproduction studies performed with crofelemer in rats at oral doses up to 177 times the recommended daily human dose of 4.2 mg/kg revealed no evidence of impaired fertility or harm to the fetus.  In pregnant rabbits, crofelemer at an oral dose of about 96 times the recommended daily human dose of 4.2 mg/kg, caused abortions and resorptions of fetuses.  However, it is not clear whether these effects are related to the maternal toxicity observed.  A pre- and postnatal development study performed with crofelemer in rats at oral doses of up to 177 times the recommended daily human dose of 4.2 mg/kg revealed no evidence of adverse pre- and postnatal effects in offspring.  There are, however, no adequate, well-controlled studies in pregnant women.  Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Nursing Mothers
It is not known whether crofelemer is excreted in human milk.  Because many drugs are excreted in human milk and because of the potential for adverse reactions in nursing infants from FULYZAQ, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into acco