Xyrem (sodium oxybate) for the treatment of cataplexy in narcolepsy

What is cataplexy in narcolepsy?

Narcolepsy is a long-term condition which causes excessive sleepiness during the day and may disrupt your sleep at night. You can also have sleep attacks where you fall asleep at inappropriate times during the day without any warning.

Cataplexy is a condition associated with narcolepsy that results in sudden muscle weakness. This can be triggered by strong emotions such as:

• laughter
• anger
• fright
• surprise

Muscle weakness can vary in severity, and cataplexy attacks can differ in both type and how long they last for.

What is sodium oxybate?

Xyrem is a brand name of sodium oxybate. Sodium oxybate can help treat cataplexy but can also help with many of the other symptoms of narcolepsy. Sodium oxybate helps deep sleep and improves night-time sleep. It helps with excessive daytime sleepiness as well as helping to control cataplexy.

It is sometimes used in combination with other medicines for narcolepsy.

How do I take the medicine?

Sodium oxybate is taken in 2 doses. The first dose is taken as you go to bed and the second dose is taken 3 to 4 hours later.

You should prepare both doses before you go to bed, and you may need to set an alarm to make sure you wake up to take the second dose. Although it seems a bit odd to wake up and take another dose it is important to follow these instructions.

The medicine comes as a liquid. You need to draw up the medicine using a syringe, and mix it with water. Use the special child-resistant dosing cups that come with the medicine.

The manufacturer’s leaflet supplied with the medicine explains how this should be done. Please refer to this for further information.

Sit upright while taking your doses. Take your second dose while still in bed and lie down again straight away.

As food interferes with how much of this medicine is absorbed by your body, you should take sodium oxybate well after eating any food. Try to take your medicine at least 2 to 3 hours after your evening meal.

What should I do if I forget to take the medicine?

If you forget to take the first dose, take it as soon as you remember and then take the second dose 3 to 4 hours later.

If you miss the second dose, do not take it when you remember (or wake up). Instead skip the dose completely and do not take any more until the following evening.

Never take 2 doses together to make up for a forgotten dose.

Are there any side effects

In addition to their desired effects, most medicines can cause unwanted side effects, although not everyone experiences them. The following are examples of some of the side effects reported by patients taking sodium oxybate. The unwanted effects often fade as your body adjusts to the new medicine, but speak with your doctor or nurse if any of the following continue or become troublesome. For further information on side effects, please see the manufacturer’s leaflet that comes with the medicine.

If you experience any of the following symptoms, contact your consultant or GP for advice as soon as possible:

• sleepwalking
• any changes to your mood, behaviour, or thinking
• any suicidal thoughts or thoughts about harming yourself
• significant change in weight or appetite

If any of the side effects persist or become a problem, contact your GP, consultant or nurse.

Can I take sodium oxybate with other medicines?

Sodium oxybate may interact with some medicines. It is important to let us know about any medicines that you are currently taking so that we can check sodium oxybate is suitable for you.

If you are buying any medicines over the counter from a pharmacy, always mention that you have been prescribed sodium oxybate. It is safe to take paracetamol and ibuprofen with this medicine but always ask your pharmacist first.

You should get advice when purchasing herbal or homeopathic remedies.

Are there any side effects?

How will my treatment be reviewed?

Your treatment will be reviewed on an ongoing basis in the Narcolepsy Clinic and the dose adjusted in response to your symptoms. Your consultant will want to check to make sure that the treatment is helping. You may need to have your blood pressure and heart rate checked regularly.

How do I get a repeat prescription?

Your consultant will provide repeat prescriptions, which will be sent in the post.

It can also be dispensed by the Rowland’s pharmacy at Sheffield Children’s hospital outpatients 0114 305 3367.

Is there anything else I need to know?

Stopping sodium oxybate

Treatment with sodium oxybate is usually long-term. Continue to take the medicine unless you are advised otherwise. Stopping suddenly can cause problems and your doctor may want you to reduce your dose gradually if this is necessary.

Driving

If you are old enough to drive, you must let the Driver and Vehicle Licensing Authority (DVLA) know if you are diagnosed with narcolepsy.

You may be allowed to drive again when your symptoms are well controlled with medication, but you will need to have regular reviews. Your consultant will advise you about this.

If you are a driver, please be aware that sodium oxybate may affect your reactions and ability to drive. It is an offence to drive while your reactions are impaired. Do not drive within 6 hours of taking a dose of sodium oxybate. You may also continue to feel sleepy during the following day, so do not drive and do not use tools or machinery if this happens, as you may put yourself and others at risk.

Even if your driving ability is not impaired, if you drive, you should carry some evidence with you which shows that the medicine has been prescribed for you. A repeat prescription form or the patient information leaflet from the packet is generally enough.

Pregnancy and breastfeeding

Sodium oxybate is not recommended for use during pregnancy. If you are considering becoming pregnant or you discover that you are pregnant you should discuss with your consultant so that a management plan can be agreed.

Sleep routine

Taking sodium oxybate is not a replacement for a good sleep routine. It is still important to aim to get around 9 to 11 hours of sleep at night, depending on your age. Try to go to bed when you’re tired and get up at about the same time each day.

Operations

If you are due to have an operation or dental treatment, it is important that you tell your consultant or GP who can advise you further.

Drinking alcohol

❌ Do not drink alcohol while you are on sodium oxybate, as it may increase the risk of side effects such as mood changes, confusion, reduced breathing rate or sleep disturbances.

Stopping sodium oxybate

Sodium oxybate is known to cause dependence, particularly where more than the recommended doses are taken. If you are concerned about this, you should discuss it with your doctor.

Sodium intake

Sodium oxybate contains a significant amount of sodium so you should limit your sodium (salt) intake. This is particularly important if you are sensitive to salt intake, for example, if you have high blood pressure.

Expiry dates

Once a bottle has been opened it will keep for 40 days. After this time, make sure you have a fresh supply. Diluted liquid should only be kept for 24 hours.

The expiry date is printed on the container. Do not use the medicine after this date.

Any unused medicine, and diluted medicine which was not used, should be returned to your local pharmacy to be thrown away.

Sodium oxybate is a controlled drug. It should be stored safely and kept out of reach of children. If anyone other than you takes this medicine, you, they, or their parent or carer should contact NHS 111 for advice. If they are unwell, they should call for an ambulance.