What is Pheburane - sodium phenylbutyrate used for?
Pheburane is a medicine that contains the active substance sodium phenylbutyrate . It is used to treat patients suffering from disorders associated with the urea cycle. These patients are not able to eliminate nitrogen residues from the body because they lack some enzymes normally found in the liver. In the body, nitrogenous residues are found in the form of ammonia which is toxic when it accumulates, especially for the brain. Pheburane is used in patients who lack one or more of the following enzymes: carbamyl phosphate synthetase, ornithine transcarbamylase or argininosuccinate synthase. It can be used in patients with the following forms of disease:
- "early onset" disease in patients who show a complete lack of one or more of these enzymes within the first few months of life;
- late-onset disease in patients who show a partial lack of one or more of these enzymes after the age of one month and have had high levels of ammonia that have affected brain activity.
Pheburane is a hybrid medicine. This means that it is similar to a "reference medicine" that contains the same active ingredient, but Pheburane grains are available at a lower dosage and contain different excipients (inactive ingredients) to mask the unpleasant taste of the active ingredient. The reference medicine for Pheburane is Ammonaps.
How is Pheburane used - sodium phenylbutyrate?
Pheburane is available in granules (483 mg / g). It can only be obtained with a prescription; the treatment must be followed by a doctor experienced in treating patients suffering from urea cycle disorders. Pheburane must be combined with a low-protein diet to reduce nitrogen intake. The daily dose of Pheburane is individually adapted for each patient and depends on the diet, height and weight of the patient. Regular blood tests are necessary to determine the exact daily dose. The daily dose of Pheburane must be divided into identical quantities and be administered with each meal. The granules may be sprinkled on the food immediately before being swallowed or placed in the mouth and immediately swallowed with a drink. Pheburane can be a long-term treatment unless the patient has a successful liver transplant.
How does Pheburane - sodium phenylbutyrate work?
Each protein carries nitrogen to the body; the nitrogen is then transformed into ammonia. Patients suffering from urea cycle disorders cannot eliminate ammonia from the body, therefore it can reach high levels, which can cause serious problems, including disability, brain injury and death. The active ingredient in Pheburane, sodium phenylbutyrate, is transformed in the body into a substance called phenylacetate. Phenylacetate combines with the amino acid glutamine, which contains nitrogen, to form a substance that can be eliminated from the body by the kidneys. This allows the nitrogen levels in the body to decrease, reducing the level of ammonia produced
What studies have been carried out on Pheburane - sodium phenylbutyrate?
Patient studies have been limited to tests to establish that Pheburane is bioequivalent to the reference medicine called Ammonaps. Two medicines are bioequivalent when they produce the same levels of active ingredient in the body.
What are the benefits and risks of Pheburane - sodium phenylbutyrate?
Because Pheburane is a hybrid medicine, bioequivalent to the reference medicine, its benefits and risks are taken as being the same as the reference medicine's.
Why has Pheburane - sodium phenylbutyrate been approved?
The Agency's Committee for Medicinal Products for Human Use (CHMP) concluded that Pheburane has been shown to have comparable quality and to be bioequivalent to Ammonaps. Therefore, the CHMP considered that, as in the case of Ammonaps, the benefits outweigh the identified risks and recommended to approve the use of Pheburane in the EU.
What measures are being taken to ensure the safe and effective use of Pheburane - sodium phenylbutyrate?
Safety information has been included in the summary of product characteristics and the package leaflet for Pheburane, including the appropriate precautions to be followed by healthcare professionals and patients.
Other information on Pheburane - sodium phenylbutyrate
On 31 July 2013, the European Commission issued a marketing authorization for Pheburane, valid throughout the European Union. For more information on Pheburane therapy, read the package leaflet (also part of the EPAR) or contact your doctor or pharmacist. Last update of this summary: 08-2013.
