Phenylbutyrate

Sodium Phenylbutyrate is a prescription medicine used for the treatment of urea cycle disorders. 

• Sodium Phenylbutyrate is available under the following different brand names: Buphenyl, Olpruva, Pheburane

Common side effects of Sodium Phenylbutyrate include:

• missed menstrual periods, 
• changes in the regular menstrual cycle, 
• loss of appetite, 
• headache, and
• unusual or unpleasant taste in the mouth

Serious side effects of Sodium Phenylbutyrate include:

• hives, 
• difficulty breathing, 
• swelling of the  face, lips, tongue, or throat, 
• dizziness, 
• mood or behavior changes, 
• memory loss, 
• thinking problems, 
• muscle twitching, 
• back and forth movement of the eyes, 
• vomiting, 
• increasing weakness, 
• slurred speech, 
• seizures, 
• fainting,
• severe drowsiness, 
• confusion, 
• swelling, 
• rapid weight gain, 
• lightheadedness, 
• pale skin, 
• shortness of breath, and
• rapid heart rate

Rare side effects of Sodium Phenylbutyrate include:

• none

Seek medical care or call 911 at once if you have the following serious side effects:

• Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors;
• Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
• Serious heart symptoms include fast, irregular, or pounding heartbeats; fluttering in the chest; shortness of breath; sudden dizziness, lightheadedness, or passing out. 

This is not a complete list of side effects and other serious side effects or health problems that may occur because of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

Adult and pediatric dosage

Tablet (Buphenyl)

• 500 mg

Powder for oral suspension (Buphenyl)

• 3 g/level teaspoon (measuring device included)
• 8.6 g/level tablespoon (measuring device included)

Oral pellets for suspension (Olpruva)

• 2 g/packet
• 3 g/packet
• 4 g/packet
• 5 g/packet
• 6 /packet
• 6.67 g/packet

Oral pellets (Pheburane)

• 84 g/bottle

Urea Cycle Disorders

Adult dosage

Buphenyl tablets, Olpruva, Pheburane

• 9.9-13 g/m²/day orally divided in 3-6 doses; not to exceed 20 g/day
• Pediatric dosage
• Weighing above 20 kg
  • Buphenyl tablets, Olpruva, Pheburane
    • 9.9-13 g/m²/day orally divided in 3-6 doses; not to exceed 20 g/day
• Weighing below 20 kg
  • Buphenyl tablets, Buphenyl powder for suspension, Pheburane
    • 450-600 mg/kg/day orally divided into 3-6 doses

Dosage Considerations – Should be Given as Follows: 

• See “Dosages”

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

• Sodium Phenylbutyrate has severe interactions with no other drugs.
• Sodium Phenylbutyrate has serious interactions with no other drugs.
• Sodium Phenylbutyrate has moderate interactions with the following drug:
  • probenecid
• Sodium Phenylbutyrate has minor interactions with no other drugs.

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all your products. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your healthcare professional or doctor for additional medical advice, or if you have health questions or concerns.

Contraindications

• Hypersensitivity
• Acute hyperammonemia

Effects of drug abuse

• None

Short-Term Effects

• See “What Are Side Effects Associated with Using Sodium Phenylbutyrate?”

Long-Term Effects

• See “What Are Side Effects Associated with Using Sodium Phenylbutyrate?”

Cautions

• Renal insufficiency, hepatic insufficiency, CHF
• Patients on restricted sodium intake (contains 125 mg Na/g)
• Powder should not be mixed with acidic liquids
• May cause sodium and fluid retention; caution in patients that poorly tolerate fluid retention like those with heart failure
• Hyperammonemia and hyperammonemia encephalopathy may occur while on therapy (manage hyperammonemia as a medical emergency
• Will not reverse existing hyperammonemia-inflicted neurologic damage
• Low protein diet is recommended with possible amino acid substitution

Pregnancy and Lactation

• Use with caution if the benefits outweigh the risks during pregnancy.
• Lactation
  • Use caution