July 29, 2016
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Side Effects


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 FULYZAQ for a mean duration of 78 days. Of the total population across the three trials, 229 patients received a dose of 125 mg twice a day for a mean duration of 141 days, 69 patients received a dose of 250 mg twice a day for a mean duration of 139 days, 102 patients received a dose of 250 mg four times a day for a mean duration of 14 days, 54 patients received a dose of 500 mg twice a day for a mean duration of 146 days, and 242 patients received a dose of 500 mg four times a day for a mean duration of 14 days.

Adverse reactions for FULYZAQ that occurred in at least 2% of patients and at a higher incidence than placebo are provided in Table 1.

Table 1: Adverse Reactions Occurring in at Least 2% of Patients in the 125 mg Twice Daily Group

Adverse Reaction Crofelemer 125 mg BID*
N = 229 n (%)
N = 274 n (%)
Upper respiratory tract infection 13 (5.7) 4 (1.5)
Bronchitis 9 (3.9) 0
Cough 8 (3.5) 3 (1.1)
Flatulence 7 (3.1) 3 (1.1)
Increased bilirubin 7 (3.1) 3 (1.1)
Nausea 6 (2.6) 4 (1.5)
Back pain 6 (2.6) 4 (1.5)
Arthralgia 6 (2.6) 0
Urinary tract infection 5 (2.2) 2 (0.7)
Nasopharyngitis 5 (2.2) 2 (0.7)
Musculoskeletal pain 5 (2.2) 1 (0.4)
Hemorrhoids 5 (2.2) 0
Giardiasis 5 (2.2) 0
Anxiety 5 (2.2) 1 (0.4)
Increased alanine aminotransferase 5 (2.2) 3 (1.1)
Abdominal distension 5 (2.2) 1 (0.4)

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.

Read the Fulyzaq (crofelemer delayed-release tablets) Side Effects Center for a complete guide to possible side effects


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].

Nelfinavir, Zidovudine, And Lamivudine

FULYZAQ administration did not have a clinically relevant interaction with nelfinavir, zidovudine, or lamivudine in a drug-drug interaction trial.

This monograph has been modified to include the generic and brand name in many instances.

Last reviewed on RxList: 4/14/2016

Side Effects

Report Problems to the Food and Drug Administration


You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

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