Sodium Phenylbutyrate

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Even with treatment, urea cycle disorders can cause a build-up of ammonia in the blood which can result in life-threatening side effects. Seek emergency medical attention if you notice any signs of ammonia build-up, including mood or behavior changes, memory loss, thinking problems, muscle twitching, back and forth movement of the eyes, vomiting, increasing weakness, slurred speech, seizure (convulsions), and fainting.

Call your doctor at once if you have:

• severe drowsiness, confusion;
• swelling, rapid weight gain;
• a light-headed feeling, like you might pass out; or
• pale skin, feeling short of breath, rapid heart rate.

Common side effects may include:

• missed menstrual periods, changes in your regular cycle;
• loss of appetite;
• headache; or
• unusual or unpleasant taste in your mouth.

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.

Sodium Phenylbutyrate is part of the drug class:

• Various alimentary tract and metabolism products

Take sodium phenylbutyrate exactly as prescribed by your doctor. Follow the directions on your prescription label carefully.

The Sodium Phenylbutyrate dose your doctor recommends will be based on the following (use any or all that apply):

• the condition being treated
• other medical conditions you have
• other medications you are taking
• how you respond to this medication
• your weight
• your height
• your age
• your gender

Sodium Phenylbutyrate is available in the following doses:

• Sodium Phenylbutyrate 100% Oral Powder For Reconstitution
• Sodium Phenylbutyrate 500 Mg Oral Tablet

Seek emergency medical attention if you notice any signs of ammonia build-up, including mood or behavior changes, memory loss, thinking problems, muscle twitching, back and forth movement of the eyes, vomiting, increasing weakness, slurred speech, seizure (convulsions), and fainting.

Sodium phenylbutyrate will not treat immediate symptoms of an ammonia build-up.

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

Be sure to take this medicine with food.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

In the U.S.

• Buphenyl
• SPB11

Available Dosage Forms:

• Tablet
• Powder
• Tablet, Enteric Coated

Therapeutic Class: Hyperammonemia Agent

Pharmacologic Class: Histone Deacetylase Inhibitor

It is very important that your doctor check your progress at regular visits to make sure that sodium phenylbutyrate is working properly. Blood tests may be needed to check for unwanted effects.

In case of emergency—There may be a time when you need emergency help for a problem caused by your urea cycle disorders. You need to be prepared for these emergencies. It is a good idea to wear a Medic Alert tag at all times. Also, carry an ID card in your wallet or purse that says you have this disease and a list of all of your medicines.

Check with your doctor right away if you have lightheadedness or sleepiness. These maybe symptoms of more serious problems.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Powder:
Less than 20 kg: 450 to 600 mg/kg/day
20 kg or Greater: 9.9 to 13 g/m2/day

Tablet:
20 kg or Less: Not recommended.
Greater than 20 kg: 9.9 to 13 g/m2/day

Comments: Administer orally in equally divided doses with each meal or feeding (i.e., 3 to 6 times a day).

Uses:
-Adjunctive therapy in the chronic management of urea cycle disorders involving deficiencies of carbamylphosphate synthetase (CPS), ornithine transcarbamylase (OTC), or argininosuccinic acid synthetase (AS).
-Treatment of neonatal-onset deficiency (complete enzymatic deficiency, presenting within the first 28 days of life) and late-onset disease (partial enzymatic deficiency, presenting after the first month of life) with history of hyperammonemic encephalopathy.