Description and Brand Names

Drug information provided by: Merative, Micromedex®

US Brand Name

  1. Ravicti

Descriptions


Glycerol phenylbutyrate is used together with a proper diet and supplements to lower high levels of ammonia in the blood caused by urea cycle disorders. This medicine is used in patients who cannot be treated with a low-protein diet and amino acid supplements alone.

Ammonia is formed from the breakdown of protein in the body. If the ammonia cannot be removed by the body, then a buildup may cause serious unwanted effects. This medicine works by helping to remove ammonia (nitrogen) from the body to reduce high levels of ammonia in the blood.

This medicine is available only with your doctor's prescription.

This product is available in the following dosage forms:

  • Solution

Before Using

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of glycerol phenylbutyrate in children. Safety and efficacy have been established.

Geriatric

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of glycerol phenylbutyrate in the elderly. However, elderly patients are more likely to have liver, kidney, or heart problems, which may require caution and an adjustment in the dose for patients receiving glycerol phenylbutyrate.

Breastfeeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Drug Interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Intestinal malabsorption (trouble absorbing food in the bowels) or
  • Pancreatic insufficiency (trouble digesting food properly caused by lack of enzymes made by the pancreas)—May not work properly in patients with these conditions.
  • Kidney disease or
  • Liver disease, moderate to severe—Higher blood levels of glycerol phenylbutyrate may increase the risk of side effects.
  • Nerve problems—Use with caution. May make this condition worse.

Proper Use

Take this medicine exactly as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered. To do so may increase the chance of side effects.

This medicine comes with a Medication Guide. Read and follow the instructions carefully. Ask your doctor if you have any questions.

It is important that you or your child follow any special diet instructions from your doctor, such as using a low-protein diet. If you have any questions about this, check with your doctor.

Use an oral syringe or dosing cup to measure your dose. You may also give this medicine through a nasogastric tube or gastrostomy tube (g-tube).

To use the oral liquid with a nasogastric tube or g-tube:

  • Use an oral syringe to measure your dose and place it on the tip of the nasogastric tube or g-tube.
  • Inject the medicine into the tube.
  • Flush the tube with 10 milliliters (mL) of water to rinse all of the medicine into the stomach.
  • Rinse the tube again with additional 10 mL of water to clear the tube.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (liquid):
    • For treatment of urea cycle disorders:
      • For patients not on phenylbutyrate treatment:
        • Adults and children 2 years of age and older—Dose is based on body size and must be determined by your doctor. The dose is 4.5 to 11.2 milliliters (mL) per square meter (m[2]) per day and divided into 3 equal doses, each rounded up to the nearest 0.5 mL. Your doctor may adjust your dose as needed. However, the dose is usually not more than 17.5 mL per day.
        • Children younger than 2 years of age—Dose is based on body size and must be determined by your doctor. The dose is 4.5 to 11.2 milliliters (mL) per square meter (m[2]) per day and divided into 3 or more equal doses, each rounded up to the nearest 0.1 mL. Your doctor may adjust your dose as needed. However, the dose is usually not more than 17.5 mL per day.
      • For patients switching from sodium phenylbutyrate powder to Ravicti®:
        • Adults and children 2 years of age and older—The dose is the total daily dose of sodium phenylbutyrate that you are already taking multiplied by 0.81 and divided into 3 equal doses, each rounded up to the nearest 0.5 milliliters (mL). Your doctor may adjust your dose as needed. However, the dose is usually not more than 17.5 mL per day.
        • Children younger than 2 years of age—The dose is the total daily dose of sodium phenylbutyrate that you are already taking multiplied by 0.81 and divided into 3 or more equal doses, each rounded up to the nearest 0.1 mL. Your doctor may adjust your dose as needed. However, the dose is usually not more than 17.5 mL per day.
      • For patients switching from sodium phenylbutyrate tablets to Ravicti®:
        • Adults and children 2 years of age and older—The dose is the total daily dose of sodium phenylbutyrate that you are already taking multiplied by 0.86 and divided into 3 equal doses, each rounded up to the nearest 0.5 milliliter (mL). Your doctor may adjust your dose as needed. However, the dose is usually not more than 17.5 mL per day.
        • Children younger than 2 years of age—The dose is the total daily dose of sodium phenylbutyrate that you are already taking multiplied by 0.86 and divided into 3 or more equal doses, each rounded up to the nearest 0.1 mL. Your doctor may adjust your dose as needed. However, the dose is usually not more than 17.5 per day.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Precautions

It is very important that your doctor check your or your child's progress at regular visits to make sure that this medicine is working properly. Blood tests may be needed to check for unwanted effects.

Check with your doctor right away if you have burning, tingling, numbness or pain in the hands, arms, feet, or legs, headache, lightheadedness, confusion, memory problems, sleepiness or unusual drowsiness, change or loss of taste, hearing loss, or unusual tiredness or weakness. 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.

Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

  1. Black, tarry stools
  2. bleeding gums
  3. blood in the urine or stools
  4. chills
  5. confusion
  6. continuing nausea or vomiting
  7. cough
  8. decreased urination
  9. dizziness
  10. drowsiness
  11. dry mouth
  12. fainting
  13. fever
  14. heartburn
  15. increase in heart rate
  16. increase in the frequency of seizures
  17. lightheadedness
  18. loss of appetite
  19. lower back or side pain
  20. muscle tremors
  21. painful or difficult urination
  22. pale skin
  23. pinpoint red spots on the skin
  24. rapid breathing
  25. rapid, deep breathing
  26. restlessness
  27. sore throat
  28. stomach cramps
  29. sunken eyes
  30. swollen glands
  31. thirst
  32. troubled breathing with exertion
  33. ulcers, sores, or white spots in the mouth
  34. unusual bleeding or bruising
  35. unusual drowsiness, dullness, tiredness, weakness, or feeling of sluggishness
  36. wrinkled skin

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  1. Agitation
  2. bloated or full feeling
  3. constipation
  4. diarrhea
  5. excess air or gas in the stomach or bowels
  6. headache
  7. irritability
  8. passing gas
  9. rash
  10. stomach pain
  11. stuffy or runny nose
  12. upper abdominal or stomach pain

Less common

  1. Belching
  2. indigestion
  3. stomach discomfort or upset

Incidence not known

  1. Abnormal body, skin, hair, and urine odor
  2. burning sensation in the mouth
  3. dry heaves
  4. gagging
  5. loss of or change in taste

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Portions of this document last updated: Feb. 01, 2024

Original article: https://www.mayoclinic.org/drugs-supplements/glycerol-phenylbutyrate-oral-route/precautions/drg-20060818