Pheburane: Uses, Side Effects and Dosage

ABOUT THIS MEDICATION

What the medication is used for:

Pheburane contains the active substance sodium phenylbutyrate which is used to treat patients of all ages with urea cycle disorders (UCD), involving deficiencies of liver enzymes, i.e. carbamylphosphate synthetase, ornithine transcarbamylase or argininosuccinate synthetase.

These liver enzymes are necessary to eliminate waste nitrogen in the form of ammonia.

Nitrogen is a building block of proteins, which are an essential part of the food we eat. As the body breaks down protein after eating, waste nitrogen, in the form of ammonia, accumulates in patients with UCD because the body cannot eliminate it. Ammonia is especially toxic for the brain and leads, in severe cases, to reduced levels of consciousness and to coma.

What it does:

Pheburane helps the body to eliminate waste nitrogen, reducing the amount of ammonia in your body. However Pheburane must be used along with a diet reduced in proteins, designed especially for you by the doctor and the dietician. You must follow this diet carefully.

When it should not be used:

Do not take Pheburane if you:

• are allergic to sodium phenylbutyrate or to any ingredient

  in the formulation.

• are pregnant.
• are breastfeeding.

What the medicinal ingredient is:

Sodium phenylbutyrate.

What the nonmedicinal ingredients are:

Ethylcellulose, hydroxypropylmethylcellulose, macrogol, maize starch, povidone and sucrose.

What dosage forms it comes in:

Pheburane consists of white to off-white tasteless coated granules. Each gram of granules contains 483 mg of sodium phenylbutyrate.

WARNINGS AND PRECAUTIONS

BEFORE using Pheburane talk to your doctor or pharmacist if you:

• suffer from congestive heart failure (a type of heart disease where the heart cannot pump enough blood around the body);

• have decreased kidney or liver function, since

  Pheburane is eliminated from the body through the kidney and liver;

• are diabetic or have been diagnosed with problems

  (i.e. intolerance, malabsorption or enzyme insufficiency) relating to some sugars.

While taking Pheburane it is still possible to experience an acute excess of ammonia in the blood. If this happens you may develop symptoms such as feeling sick (nausea), being sick (vomiting), confusion, combativeness, slurred speech, difficulty walking, and even loss of consciousness. This is a medical emergency, and medical assistance should be sought immediately. An infection can cause such a situation; therefore, if you develop a fever you should seek prompt medical assistance.

If you need laboratory tests, it is important to remind your doctor that you are taking Pheburane, since Pheburane may affect certain blood test results.

Pregnancy and breastfeeding:

Do not use Pheburane if you are pregnant, because this medicine can harm your unborn baby.

If you are a woman who could become pregnant, you must use reliable contraception during treatment with Pheburane and should speak with your doctor.

Do not use Pheburane if you are breastfeeding, because this medicine may pass into the breast milk and may harm your baby.

Driving and using machines:

Pheburane is unlikely to affect the ability to drive and use machines. However, these abilities may be limited by the effects of the UCD, as well as the associated risk of episodes of hyperammonemia.

Pheburane contains sodium and sucrose:

This medicine contains 124 mg of sodium per 1 g of sodium phenylbutyrate. This should be taken into consideration if you are on a sodium-controlled diet.

This medicine contains 768 mg of sucrose per 1 g of sodium phenylbutyrate. This should be taken into account if you have diabetes.

INTERACTIONS WITH THIS MEDICATION

Tell your doctor or pharmacist if you are taking, have recently taken or might take any other medicines.

It is especially important to tell your doctor if you are taking

medicines containing:

• valproate, topiramate, phenobarbital, or carbamazepine

  (antiepileptic medicines);

• haloperidol (used in certain psychotic disorders);

• corticosteroids (medicines that are used to provide relief

  for inflamed areas of the body);

• probenecid (for treatment of hyperuricaemia, high levels

  of uric acid in the blood, associated with gout).

These medicines may change the effect of Pheburane and you may need more frequent blood tests. If you are uncertain if your medicines contain these substances, you should check with your doctor or pharmacist.

PROPER USE OF THIS MEDICATION

Always take this medicine exactly as your doctor has told you. Check with your doctor or pharmacist if you are not sure.

Usual dose:

The daily dose will be based on your body weight or body surface area and adjusted according to your protein tolerance and diet. You will need regular blood tests to determine the correct daily dose.

Your doctor will tell you the amount of granules to take as well as the number of doses you should take per day.

Your total dose per day should not exceed 20 grams.

Method of administration:

You should take Pheburane by mouth.

A special diet reduced in protein must also be

followed when taking Pheburane.

You should take Pheburane with each meal or feeding. In small children this can be 4 to 6 times per day.

A calibrated measuring spoon is provided with the medicine. The spoon directly measures Pheburane granules as sodium phenylbutyrate. The spoon

dispenses up to 3 g of sodium phenylbutyrate in

increments of 0.25 g. Only use this calibrated

measuring spoon to measure out the dose.

To measure the dose:

• Lines on the spoon indicate the amount (in grams of

  sodium phenylbutyrate). Take the correct amount as prescribed by your doctor.

• Pour granules directly into the spoon as shown by the

  picture below.

• Tap the spoon once on a table to give a horizontal level of

  granules and continue filling if necessary.

  • If you must take more than 3 grams at once, repeat these instructions to obtain the prescribed dose.

The granules can be directly swallowed with a drink (water, fruit juices, protein-free infant formulas) or sprinkled on to a spoonful of solid foods (mashed potatoes or apple sauce). If you mix them with food, it is important that you take it immediately. This will keep the granules from producing any taste.

Administration by nasogastric tube or gastrostomy tube: In certain circumstances, your doctor may decide that Pheburane should be administered through nasogastric tube (a tube that goes through the nose to the stomach) or gastrostomy tube (a tube that goes through the abdomen to the stomach). In this case, Pheburane will be prepared into a liquid by hospital or pharmacy staff following specific instructions. Granules should not be taken directly by tube. The exact amount of liquid to measure into the syringe will be determined by your doctor. Do not use the calibrated measuring spoon provided with the product to measure the liquid.

The liquid must be given with a syringe by fast push directly through the tube. Rinse with water to clear the nasogastric or gastrostomy tube.

Overdose:

You may experience the following symptoms if you take more Pheburane than you should:

• sleepiness,
• tiredness,
• light-headedness,

And less frequently:

• confusion,
• headache,
• changes in taste (taste disturbances),
• decrease in hearing,
• disorientation,
• impaired memory, and
• worsening of existing neurological conditions.

If you think you have taken too much Pheburane, contact your healthcare professional, hospital emergency department or regional Poison Control Centre immediately, even if there are no symptoms.

Missed Dose:

You should take a dose as soon as possible with your next meal. Make sure that there are at least 3 hours between two doses. Do not take a double dose to make up for a forgotten dose.

If you have any further questions on the use of this medicine, ask your doctor or pharmacist.

SIDE EFFECTS AND WHAT TO DO ABOUT THEM

These are not all the possible side effects you may feel when taking Pheburane. If you experience any side effects not listed here, contact your healthcare professional.

The most common side effects associated with treatment are changes in menstruation or cessation of your period, reduced appetite, body odor, changes in taste, changes in the number of blood cells and other changes in the blood including levels of: pH (more or less acidic than normal), proteins, enzymes and electrolytes.

If you have a troublesome symptom or side effect that is not listed here or becomes bad enough to interfere with your daily activities, talk to your healthcare professional.

HOW TO STORE IT

Keep out of the sight and reach of children.

Store Pheburane granules at room temperature (15 to 30°C).

After the first opening, Pheburane granules should be used within 45 days.

Pheburane solution for nasogastric or gastrostomy administration:

Store between 2°C and 8°C.

Protect from light.

After preparation, Pheburane solution should be used within 7 days.

Reporting Side Effects

You can report any suspected side effects associated with the use of health products to Health Canada by:

• Visiting the Web page on Adverse Reaction Reporting

  (https://www.canada.ca/en/health-canada/services/drugs-health-products/medeffect-canada/adverse-reaction-reporting.html) for information on how to report online, by mail or by fax; or

• Calling toll-free at 1-866-234-2345.

NOTE: Contact your health professional if you need information about how to manage your side effects. The Canada Vigilance Program does not provide medical advice.

MORE INFORMATION

This document plus the full product monograph, prepared for health professionals can be obtained by contacting Médunik Canada at:

950, boul. Michèle-Bohec

Blainville, Québec, Canada

J7C 5E2

Tel: 1-855-633-8645

Fax: 1-888-588-8508

www.medunikcanada.com

Last revised: December 6, 2017