Sodium benzoate / sodium phenylacetate Side Effects

Some side effects of sodium benzoate / sodium phenylacetate may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

For the Consumer

Applies to sodium benzoate / sodium phenylacetate: intravenous solution

Other dosage forms:

Along with its needed effects, sodium benzoate / sodium phenylacetate may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur while taking sodium benzoate / sodium phenylacetate:

More common
  • Abdominal or stomach pain or cramps
  • blurred vision
  • decreased urine
  • dry mouth
  • fatigue
  • flushed, dry skin
  • fruit-like breath odor
  • increased hunger
  • increased thirst
  • increased urination
  • irregular heartbeat
  • loss of appetite
  • muscle pain or cramps
  • nausea or vomiting
  • numbness or tingling in the hands, feet, or lips
  • seizures
  • shortness of breath
  • sweating
  • troubled breathing
  • unexplained weight loss
  • unusual tiredness or weakness
Less common
  • Agitation
  • anxiety
  • bleeding, blistering, burning, coldness, discoloration of the skin, feeling of pressure, hives, infection, inflammation, itching, lumps, numbness, pain, rash, redness, scarring, soreness, stinging, swelling, tenderness, tingling, ulceration, or warmth at the injection site
  • bleeding or oozing from the puncture site, mouth, or nose that continues
  • bloody or cloudy urine
  • bloody, black, or tarry stools
  • confusion
  • coughing that sometimes produces a pink frothy sputum
  • depression
  • dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
  • drowsiness
  • feeling, seeing, or hearing things that are not there
  • feeling that others are watching you or controlling your behavior
  • headache
  • lightheadedness
  • mood or mental changes
  • muscle tremors
  • nightmares or unusually vivid dreams
  • pale skin
  • rapid, deep breathing
  • restlessness
  • skin rash
  • sleepiness or unusual drowsiness
  • trouble with breathing when moving or walking
  • unusual bleeding or bruising

Some side effects of sodium benzoate / sodium phenylacetate may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common
  • Diarrhea
  • fever

For Healthcare Professionals

Applies to sodium benzoate / sodium phenylacetate: intravenous solution


The most common side effects are vomiting, hyperglycemia, hypokalemia, convulsions, and mental impairment


Very common (10% or more): Gastrointestinal disorders (13%)
Common (1% to 10%): Vomiting (9%), diarrhea (3%), nausea (3%)
Frequency not reported (less than 3%): Abdominal distension, gastrointestinal hemorrhage


Common (1% to 10%): Hyperglycemia (7%), hypokalemia (7%), hyperammonemia (5%), metabolic acidosis (4%), acidosis (3%), hypocalcemia (3%)
Frequency not reported (less than 3%): Alkalosis, dehydration, fluid overload/retention, hypoglycemia, hyperkalemia, hypernatremia, alkalosis, tetany

Nervous system

Very common (10% or more): Nervous system disorders (22%)
Common (1% to 10%): Mental impairment (6%), convulsions (6%), brain edema (5%), coma (3%),
Frequency not reported (less than 3%): Areflexia, ataxia, brain infarction, brain hemorrhage, cerebral atrophy, clonus, depressed level of consciousness, encephalopathy, nerve paralysis, intracranial pressure increased, subdural hematoma, tremor


Very common (10% or more): Blood and lymphatic disorders (11%)
Common (1% to 10%): Anemia (4%), disseminated intravascular coagulation (3%)
Frequency not reported (less than 3%): Coagulopathy, pancytopenia, thrombocytopenia, hemorrhage, phlebothrombosis/thrombosis


Very common (10% or more): Respiratory, thoracic and mediastinal disorders (15%)
Common (1% to 10%): Respiratory distress (3%)
Frequency not reported (less than 3%): Acute respiratory distress syndrome, dyspnea, hypercapnia, hyperventilation, Kussmaul respiration, pneumonia aspiration, pneumothorax, pulmonary hemorrhage, pulmonary edema, respiratory acidosis or alkalosis, respiratory arrest/failure


Very common (10% or more): Psychiatric disorders (5%)
Common (1% to 10%): Agitation (3%)
Frequency not reported (less than 3%): Acute psychosis, aggression, confusional state, hallucinations


Common (1% to 10%): Urinary disorders (4%), urinary tract infection (3%)


Common (1% to 10%): Skin and subcutaneous tissue disorders (6%)
Frequency not reported (less than 3%): Alopecia, blister, generalized pruritus, rash, urticaria


Frequency not reported (less than 3%): Cholestasis, hepatic artery stenosis, hepatic failure/hepatotoxicity, jaundice


Very common (10% or more): General disorders and administration- site conditions (14%), infections (12%), injury, poisoning and procedural complications (12%)
Common (1% to 10%): Pyrexia (5%), injection -site reaction (3%)
Frequency not reported (less than 3%): Asthenia, brain death, chest pain, multiorgan failure, edema, sepsis/septic shock, brain herniation, subdural hematoma, overdose, blood carbon dioxide changes, blood glucose changes, blood pH increased, cardiac output decreased, pCO2 changes, respiratory rate increased


Common (1% to 10%): Renal disorders (4%)
Frequency not reported (less than 3%): Anuria, renal failure, urinary retention


Frequency not reported (less than 3%): Blindness


Frequency not reported (less than 3%): Hemangioma acquired


Common (1% to 10%): Cardiac disorders (9%), vascular disorders (6%), hypotension (4%)
Frequency not reported (less than 3%): Atrial rupture, bradycardia, cardiac or cardiopulmonary arrest/failure, cardiogenic shock, cardiomyopathy, pericardial effusion, flushing, hypertension

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.