Complete adverse effect profile including incidence rates and management
Important Safety Information
This is not a complete list of all possible side effects. Contact your healthcare provider if you experience any unexpected symptoms. For serious or life-threatening side effects, seek emergency medical attention immediately.
ADVERSE REACTIONS The assessment of clinical adverse events came from 206 patients treated with sodium phenylbutyrate.
Adverse events (both clinical and laboratory) were not collected systematically in these patients, but were obtained from patient visit reports by the 65 co-investigators.
Causality of adverse effects is sometimes difficult to determine in this patient population because they may result from either the underlying disease, the patient’s restricted diet, intercurrent illness, or sodium phenylbutyrate.
Furthermore, the rates may be underestimated because they were reported primarily by parent or guardian and not the patient.
Clinical Adverse Events In female patients, the most common clinical adverse event reported was amenorrhea/menstrual dysfunction (irregular menstrual cycles), which occurred in 23% of the menstruating patients.
Decreased appetite occurred in 4% of all patients.
Body odor (probably caused by the metabolite, phenylacetate) and bad taste or taste aversion were each reported in 3% of patients.
Other adverse events reported in 2% or fewer patients were: Gastrointestinal : abdominal pain, gastritis, nausea and vomiting;
constipation, rectal bleeding, peptic ulcer disease, and pancreatitis each occurred in one patient.
Hematologic : aplastic anemia and ecchymoses each occurred in one patient.
WARNINGS Each sodium phenylbutyrate tablet contains 62 mg of sodium (9.2% w/w) (corresponding to 124 mg of sodium per gram of sodium phenylbutyrate [12.4% w/w]).
Sodium phenylbutyrate should be used with great care, if at all, in patients with congestive heart failure or severe renal insufficiency, and in clinical states in which there is sodium retention with edema.
Because sodium phenylbutyrate is metabolized in the liver and kidney, and phenylacetylglutamine is primarily excreted by the kidney, use caution when administering the drug to patients with hepatic or renal insufficiency or inborn errors of beta oxidation.
Probenecid is known to inhibit the renal transport of many organic compounds, including hippuric acid, and may affect renal excretion of the conjugated product of sodium phenylbutyrate as well as its metabolite.
Use of corticosteroids may cause the breakdown of body protein and increase plasma ammonia levels.
Like all medications, Sodium Phenylbutyrate can cause side effects. However, not everyone who takes this medication will experience them. Many side effects are dose-dependent and may improve as your body adjusts to the medication. Others may require dose adjustment or medical attention.
Contact your healthcare provider promptly if you experience:
Seek immediate emergency medical care if you experience signs of: