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Ammonul Side Effects Center
Medical Editor: John P. Cunha, DO, FACOEP
Ammonul (sodium phenylacetate and sodium benzoate) is used as adjunctive therapy to treat excess ammonia in the blood (acute hyperammonemia) and associated brain disease or damage (encephalopathy) in patients with deficiencies in enzymes of the urea cycle. Common side effects include low blood pressure, nausea, vomiting and diarrhea.
The dilution and dosage of Ammonul are determined by weight for neonates, infants and young children, and by body surface area for larger patients, including older children, adolescents, and adults. Ammonul may interact with antibiotics, probenecid, valproic acid, or corticosteroids. Tell your doctor all medications and supplements you use. During pregnancy, Ammonul should be used only if prescribed. It is unknown if this drug passes into breast milk. Consult your doctor before breastfeeding.
Our Ammonul (sodium phenylacetate and sodium benzoate) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
What is Prescribing information?
The FDA package insert formatted in easy-to-find categories for health professionals and clinicians.
Ammonul FDA Prescribing Information: 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 clinical practice.
The safety data were obtained from 316 patients who received AMMONUL as emergency (rescue) or prospective treatment for hyperammonemia as part of an uncontrolled, open-label study. The study population included patients between the ages of 0 to 53 years with a mean (SD) of 6.2 (8.54) years; 51% were male and 49% were female who had the following diagnoses: OTC (46%), ASS (22%), CPS (12%), ASL (2%), ARG ( < 1%), THN ( < 1%), and other (18%).
Table 2: Adverse Reactions Occurring in ≥ 3% of Patients
Treated with AMMONUL
|Number of patients with any adverse event||163 (52%)|
|Blood and lymphatic system disorders||35 (11%)|
|Disseminated intravascular coagulation||11 (3%)|
|Cardiac disorders||28 (9%)|
|Gastrointestinal disorders||42 (13%)|
|General disorders and administration-site conditions||45 (14%)|
|Injection-site reaction||11 (3%)|
|Urinary tract infection||9 (3%)|
|Injury, poisoning and procedural complications||12 (4%)|
|Metabolism and nutrition disorders||67 (21%)|
|Metabolic acidosis||13 (4%)|
|Nervous system disorders||71 (22%)|
|Brain edema||17 (5%)|
|Mental impairment||18 (6%)|
|Psychiatric disorders||16 (5%)|
|Renal and urinary disorders||14 (4%)|
|Respiratory, thoracic and mediastinal disorders||47 (15%)|
|Respiratory distress||9 (3%)|
|Skin and subcutaneous tissue disorders||19 (6%)|
|Vascular disorders||19 (6%)|
Adverse reactions were reported with similar frequency in patients with OTC, ASS, CPS, and diagnoses categorized as “other.” Nervous system disorders were more frequent in patients with OTC and CPS, compared with patients with ASS and patients with “other” diagnoses. Convulsions and mental impairment were reported in patients with OTC and CPS. These observations are consistent with literature reports that patients with enzyme deficiencies occurring earlier in the urea cycle (i.e., OTC and CPS) tend to be more severely affected.
Adverse reactions profiles differed by age group. Patients ≤ 30 days of age had more blood and lymphatic system disorders and vascular disorders (specifically hypotension), while patients > 30 days of age had more gastrointestinal disorders (specifically nausea, vomiting and diarrhea).
Less common adverse reactions ( < 3% of patients) that are characterized as severe are listed below by body system.
EYE DISORDERS: blindness
GASTROINTESTINAL DISORDERS: abdominal distension, gastrointestinal hemorrhage
INFECTIONS AND INFESTATIONS: sepsis/septic shock
NEOPLASMS BENIGN, MALIGNANT AND UNSPECIFIED: hemangioma acquired
NERVOUS SYSTEM DISORDERS: areflexia, ataxia, brain infarction, brain hemorrhage, cerebral atrophy, clonus, depressed level of consciousness, encephalopathy, nerve paralysis, intracranial pressure increased, subdural hematoma, tremor
PSYCHIATRIC DISORDERS: acute psychosis, aggression, confusional state, hallucinations
RENAL AND URINARY DISORDERS: anuria, renal failure, urinary retention
RESPIRATORY, THORACIC AND MEDIASTINAL DISORDERS: acute respiratory distress syndrome, dyspnea, hypercapnia, hyperventilation, Kussmaul respiration, pneumonia aspiration, pneumothorax, pulmonary hemorrhage, pulmonary edema, respiratory acidosis or alkalosis, respiratory arrest/failure
VASCULAR DISORDERS: flushing, hemorrhage, hypertension, phlebothrombosis/thrombosis
Read the entire FDA prescribing information for Ammonul (Sodium Phenylacetate and Sodium Benzoate Injection) »
Additional Ammonul Information
- Ammonul Drug Interactions Center: sodium benzoate-sod phenylacet iv
- Ammonul Side Effects Center
- Ammonul FDA Approved Prescribing Information including Dosage
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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