Sodium phenylbutyrate

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Generic Name: Sodium phenylbutyrate Brand Name(s): Generics only. No brands available.

Uses

What is Sodium phenylbutyrate used for?

Sodium phenylbutyrate is used along with diet changes for long-term treatment of a certain inherited disorder (urea cycle disorder). It helps remove a certain chemical (ammonia) from the body. Too much ammonia in the body can cause brain damage and sometimes death.

This medication should not be used to treat sudden, severely high levels of ammonia in the body. Seek immediate medical attention if you have sudden symptoms of too much ammonia, such as trouble thinking, vomiting, irritability, slurred speech, trouble walking, fainting.

How should I take Sodium phenylbutyrate?

Take this medication by mouth exactly as directed by your doctor. The dosage is based on your weight or body size, medical condition, and response to treatment. The total daily dose should be divided into equal amounts and taken with each meal or feeding (such as 3 to 6 times daily). Do not increase or decrease your dose without your doctor’s approval.

Use this medication regularly to get the most benefit from it. To help you remember, take it at the same times each day.

How do I store Sodium phenylbutyrate?

Sodium phenylbutyrate is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store Sodium phenylbutyrate in the bathroom or the freezer. There may be different brands of Sodium phenylbutyrate that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush Sodium phenylbutyrate down the toilet or pour them into a drain unless instructed to do so. It is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Precautions & warnings

What should I know before using Sodium phenylbutyrate?

Before taking this medication, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: a certain heart problem (congestive heart failure), kidney disease, liver disease, swelling (edema).

This medication contains salt (sodium). Before taking this medication, tell your doctor or pharmacist if you are on a low-salt diet.

This drug may make you drowsy. Alcohol or marijuana can make you more drowsy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

This medication must not be used during pregnancy. It may harm an unborn baby. Discuss the use of reliable forms of birth control (such as condoms, birth control pills) with your doctor. If you become pregnant or think you may be pregnant, tell your doctor right away.

It is unknown if this medication passes into breast milk. Consult your doctor before breast-feeding.

Is it safe during pregnancy or breast-feeding?

There are no adequate studies in women for determining risk when using this Sodium phenylbutyrate during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking Sodium phenylbutyrate. Sodium phenylbutyrate is pregnancy risk category C according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A=No risk,
  • B=No risk in some studies,
  • C=There may be some risk,
  • D=Positive evidence of risk,
  • X=Contraindicated,
  • N=Unknown

Side effects

What side effects can occur from Sodium phenylbutyrate?

Loss of appetite or menstrual changes (delayed/irregular/absent periods) may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including: drowsiness/lightheadedness, easy bruising/bleeding, fast/pounding heartbeat, mental/mood changes, signs of infection (such as fever, persistent sore throat), tiredness, signs of metabolic imbalance (such as rapid breathing, muscle twitching/spasms).

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.

Interactions

What drugs may interact with Sodium phenylbutyrate?

Sodium phenylbutyrate may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, nonprescription drugs and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.

Does food or alcohol interact with Sodium phenylbutyrate?

Sodium phenylbutyrate may interact with food or alcohol by altering the way the drug works or increase the risk for serious side effects. Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with Sodium phenylbutyrate?

Sodium phenylbutyrate may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have.

Dosage

The information provided is not a substitute for any medical advice. You should ALWAYS consult with your doctor or pharmacist before using this Sodium phenylbutyrate.

What is the dose of Sodium phenylbutyrate for an adult?

Usual Adult Dose for Urea Cycle Disorders

Powder and Tablet:

Less than 20 kg: 450 to 600 mg/kg/day

20 kg or Greater: 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.

Renal Dose Adjustments

Renal Insufficiency: Use with caution.

Liver Dose Adjustments

Hepatic Insufficiency: Use with caution.

Other Comments

Administration Advice:

-Initiate treatment immediately to improve survival and clinical outcomes.

-Administer the powder formulation orally via mouth or tube (gastrostomy or nasogastric).

-For the powder formulation, lightly shake the bottle before use.

-Consult the manufacturer product information for nutritional management recommendations.

Storage Requirements:

-When dissolved in water, the powder formulation is stable for up to one week at room temperature or under refrigeration.

Reconstitution/Preparation Techniques:

-Mix the powder formulation with food (solid or liquid, e.g., mashed potatoes, apple sauce, water, apple juice, protein-free infant formula) for immediate use.

-When the powder formulation is added to a liquid, only the active substance will dissolve; the excipients will not dissolve.

General:

-For each gram of sodium phenylbutyrate administered, between 0.12 to 0.15 grams of phenylacetylglutamine nitrogen are produced.

-The safety and efficacy of doses in excess of 20 g/day have not been established.

-This drug may be required life-long unless orthotopic liver transplantation is elected.

-In the event of an overdose, hemodialysis or peritoneal dialysis may be beneficial.

Monitoring:

-Urinalysis, hematological tests, blood chemistry profile, serum potassium, serum proteins, and plasma levels of glutamine, ammonia, arginine, branched-chain amino acids (routinely)

-Serum levels of phenylbutyrate, phenylacetate, phenylacetylglutamine (periodically)

What is the dose of Sodium phenylbutyrate for a child?

Usual Pediatric Dose for Urea Cycle Disorders

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.

How is Sodium phenylbutyrate available?

Sodium phenylbutyrate is available in the following dosage forms and strengths:

  • Oral powder for reconstitution,
  • Oral tablet.

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to your nearest emergency room.

What should I do if I miss a dose?

If you miss a dose of Sodium phenylbutyrate, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.

Hello Health Group does not provide medical advice, diagnosis or treatment.

Sources

Review Date: April 26, 2018 | Last Modified: April 26, 2018

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