Sodium oxybate

Sodium oxybate is a powerful sedative used to treat cataplexy but can also help with many of the other symptoms of narcolepsy, including excessive daytime sleepiness and sleep paralysis. Sodium oxybate is often thought of as the most effective treatment for narcolepsy with cataplexy, either on its own or in combination with one or more stimulants. However, not all patients find it beneficial. There is also some evidence that sodium oxybate helps reduce the symptoms of idiopathic hypersomnia.

At present, sodium oxybate is only manufactured by one company (Jazz Pharmaceuticals, Xyrem®) so is much more expensive than most of the other narcolepsy medication. Unfortunately, this means that many patients who might benefit from this medication are unable to access it.

Unlike the other drugs to treat the symptoms of narcolepsy and cataplexy, sodium oxybate is a liquid. It is taken as two doses, one swallowed immediately before bedtime and the other around 3-4 hours later. It is therefore necessary to set an alarm to wake in time to take the second dose. The two doses are prepared by measuring the appropriate amount of liquid into a cup using a special syringe. The cups and syringe are supplied with each box of Xyrem. The maximum dose of Xyrem is 9g (9 grams) per day, i.e. two doses of 4.5g each. This is a much higher amount of drug than is usual for most other medications, for which the doses are measured in milligrams. In practice, your doctor will initially prescribe a low dose, for instance 2 x 1.5g or 2 x 2.25g, and then gradually increase the dose until the optimum dose for you is found.

Sodium oxybate is a Schedule 2 Controlled Drug, which means that you may be required to prove your identity when collecting your prescription and you must store the drug securely.

Because sodium oxybate is a powerful sedative, it is vitally important that if you are taking it you do not drink alcohol, since the combined sedative effect of the drug and alcohol could be extremely dangerous.

Sodium oxybate - BNF

Sodium oxybate - Guys' Information Leaflet

Side effects

As with any medication, the drugs used to treat narcolepsy can have side-effects. These can take many forms. They may be relatively minor, such as mild headaches or a dry mouth, or much more serious, such as anxiety or depression. You should check the Patient Information Leaflet (PIL) in the packaging of your medication for more details and if you experience any of these side-effects (or any not on the PIL) you should consult your doctor or pharmacist.

You can also report side effects directly via the Yellow Card Scheme. By reporting side effects you can help improve the safety of this medicine.

References

Alshaikh, M.K. et al. (2012) Sodium oxybate for narcolepsy with cataplexy: systematic review and meta-analysis. J. Clin. Sleep Med. 8:451-458

Evangelista, E. et al. (2018) Expert Opin. Investig. Drugs 27: 187-192