The most common adverse reactions reported in clinical trials (at least 10% of patients) were:
Adult patients: diarrhea, flatulence, and headache occurred during 4-week treatment (n=45) with glycerol phenylbutyrate; nausea, vomiting, diarrhea, decreased appetite, dizziness, headache, and fatigue occurred during 12-month treatment (n=51) with glycerol phenylbutyrate.
Pediatric patients ages 2 to 17 years: upper abdominal pain, rash, nausea, vomiting, diarrhea, decreased appetite, and headache occurred during 12-month treatment (n=26) with glycerol phenylbutyrate.
Pediatric patients ages 2 months to less than 2 years: neutropenia, vomiting, constipation, diarrhea, pyrexia, hypophagia, cough, nasal congestion, rhinorrhea, rash, and papule occurred during 12-month treatment (n=17) with glycerol phenylbutyrate.
Pediatric patients less than 2 months of age: vomiting, rash, gastroesophageal reflux, increased hepatic enzymes, feeding disorder (decreased appetite, hypophagia), anemia, cough, dehydration, metabolic acidosis, thrombocytosis, thrombocytopenia, neutropenia, lymphocytosis, diarrhea, flatulence, constipation, pyrexia, lethargy, and irritability/agitation occurred during 24-month treatment (n=16) with glycerol phenylbutyrate.
The following adverse reactions have been identified during post-approval use of glycerol phenylbutyrate