Drug Guide
Sodium Benzoate; Sodium Phenylacetate
Classification
Therapeutic: Metabolic disorder treatment (hyperammonemia)
Pharmacological: Amino acid derivative, ammonia scavenger
FDA Approved Indications
- Treatment of select cases of hyperammonemia, especially in urea cycle disorders
Mechanism of Action
Sodium phenylacetate conjugates with glutamine to form phenylacetylglutamine, which is excreted in urine, reducing ammonia levels. Sodium benzoate conjugates with glycine to form hippuric acid, which is also excreted in urine, helping lower ammonia levels.
Dosage and Administration
Adult: Dosage varies based on clinical response; typically administered via IV in acute settings, titrated to ammonia reduction.
Pediatric: Dosing is weight-based; administered IV under medical supervision.
Geriatric: Use with caution; adjust based on renal function and clinical response.
Renal Impairment: Adjust dosing; monitor ammonia levels and renal function.
Hepatic Impairment: Use with caution; monitor clinical response.
Pharmacokinetics
Absorption: Rapid absorption when administered IV.
Distribution: Well distributed in tissues; crosses blood-brain barrier.
Metabolism: Metabolized in the liver to conjugates for excretion.
Excretion: Excreted primarily via urine.
Half Life: Typically 1-2 hours in plasma, but may vary depending on renal function.
Contraindications
- Hypersensitivity to sodium benzoate or sodium phenylacetate.
Precautions
- Monitor serum ammonia levels; renal function; electrolyte status; acid-base balance. Use caution in patients with renal impairment, metabolic acidosis, or sodium overload.
Adverse Reactions - Common
- Electrolyte imbalance (e.g., hyponatremia, hypernatremia) (Common)
- Nausea, vomiting (Common)
- Dizziness, headache (Common)
Adverse Reactions - Serious
- Allergic reactions (rash, pruritus, swelling) (Serious)
- Metabolic acidosis (Serious)
- Hypersensitivity reactions including anaphylaxis (Serious)
Drug-Drug Interactions
- Other nephrotoxic drugs, diuretics affecting electrolytes, drugs affecting renal function.
Drug-Food Interactions
- Limited data; monitor sodium intake and dietary considerations.
Drug-Herb Interactions
- Limited data; caution with herbal products affecting renal function or electrolytes.
Nursing Implications
Assessment: Monitor serum ammonia, electrolytes, renal function, acid-base status, and neurological status.
Diagnoses:
- Risk for electrolyte imbalance
- Risk for altered mental status due to hyperammonemia.
Implementation: Administer as ordered, typically IV; monitor vital signs and laboratory parameters frequently.
Evaluation: Assess ammonia levels consistently to evaluate treatment efficacy.
Patient/Family Teaching
- Report any allergic reactions promptly.
- Maintain adequate hydration; adhere to dietary and medication instructions.
- Inform healthcare providers of all medications and supplements taken.
Special Considerations
Black Box Warnings:
- Potential for serious adverse reactions including hypersensitivity and metabolic acidosis.
Genetic Factors: N/A for these medications.
Lab Test Interference: May affect serum electrolyte and acid-base tests.
Overdose Management
Signs/Symptoms: Severe metabolic acidosis, electrolyte disturbances, hypersensitivity reactions.
Treatment: Discontinue drug, provide supportive care, correct electrolyte imbalances, administer IV fluids, and treat allergic reactions as needed.
Storage and Handling
Storage: Store at room temperature, protected from light and moisture.
Stability: Stable when stored properly; use within expiration date.