Ravicti is a prescription medication used for the long-term management of elevated blood ammonia levels in individuals diagnosed with a urea cycle disorder (UCD). This oral liquid medicine is intended for use in patients of various ages, from infants to adults. It serves as an additional therapy for patients whose condition cannot be adequately managed through dietary protein restriction and amino acid supplementation alone. Ravicti works to help the body eliminate excess nitrogen, which can otherwise accumulate as harmful ammonia.
Understanding Urea Cycle Disorders
Urea cycle disorders (UCDs) are genetic conditions that affect the body’s ability to remove excess nitrogen, a byproduct of protein metabolism. Normally, the liver processes this nitrogen into urea, a harmless substance that is then excreted by the kidneys through urine. This process involves a series of enzymes, and if one or more of these enzymes are missing or not working correctly, the urea cycle cannot properly convert ammonia into urea.
When the urea cycle is disrupted, ammonia can build up in the bloodstream, a condition known as hyperammonemia. Ammonia is highly toxic to the brain and nervous system, and its accumulation can lead to severe neurological damage, coma, or even death if not managed. Maintaining stable ammonia levels is a significant aspect of managing UCDs to prevent these serious health consequences.
How Ravicti Works and Its Purpose
Ravicti, which contains the active substance glycerol phenylbutyrate, functions as a nitrogen-binding agent. Once ingested, glycerol phenylbutyrate is converted in the body to phenylacetate (PAA). PAA then combines with glutamine, an amino acid, to form phenylacetylglutamine (PAGN). This newly formed compound, PAGN, can then be excreted by the kidneys, effectively helping to remove excess nitrogen from the body in a pathway that bypasses the impaired urea cycle.
The purpose of Ravicti is to provide chronic management for patients with UCDs who struggle to control their ammonia levels through diet alone. This medication helps to continuously reduce the amount of ammonia in the blood, thereby lowering the risk of hyperammonemia-related complications. However, it is not intended for the urgent treatment of acutely high ammonia levels, as more rapid interventions are necessary in such situations.
Administering Ravicti and Important Safety Information
Ravicti is available as an oral liquid and should be taken by mouth with food or infant formula. The total daily dosage is divided into three equal amounts and administered with each meal. It can be given directly into the mouth using an oral syringe or administered through a nasogastric (NG) or gastric feeding tube.
The dosage of Ravicti is determined by a physician experienced in UCD management and depends on factors such as the patient’s diet, height, and weight. Regular blood tests are necessary to monitor ammonia and phenylacetate levels and adjust the dose as needed. Ravicti must be used alongside a low-protein diet and, in some cases, dietary supplements.
Ravicti may cause side effects, with common ones including headache, flatulence, and diarrhea. More serious side effects can involve the nervous system due to the accumulation of phenylacetate (PAA), a breakdown product of Ravicti. Symptoms of potential neurotoxicity include:
Sleepiness
Lightheadedness
Changes in taste or hearing
Confusion
Memory problems
Worsening numbness or tingling
Headache
Fatigue
Nausea and vomiting
If these symptoms occur without high ammonia levels or other clear causes, a doctor should be contacted immediately, as a dosage reduction may be necessary.
Patients should inform their doctor about all existing medical conditions, especially liver, kidney, pancreas, or bowel problems, before starting Ravicti. It is not known if Ravicti is harmful to an unborn baby or if it passes into breast milk, so pregnant or breastfeeding individuals should discuss these concerns with their healthcare provider. Allergic reactions, though rare, can occur, and symptoms such as:
Wheezing
Shortness of breath
Cough
Low blood pressure
Flushing
Nausea
Rash
These require immediate medical attention.
Ravicti can interact with other medications, potentially decreasing the effectiveness of drugs that are substrates of CYP3A4. Patients should inform their doctor about all prescription and over-the-counter medicines, vitamins, and herbal products they are taking to avoid possible interactions. Ravicti is a prescription medication and requires ongoing medical supervision and monitoring to ensure its safe and effective use.