Xyrem and Brain Dopamine in Narcolepsy

Does Xyrem Influence Brain Dopamine in Patients With Narcolepsy? A PET Imaging Investigation

The overall aim of this investigation is to establish whether an action of Xyrem® on the brain dopamine system in patients with narcolepsy, and in a comparison control group, might explain part of the anti-narcoleptic effect of the drug.

Trial Objective is to establish, using positron emission tomography (PET), in Xyrem®-naïve narcolepsy with cataplexy patients, and in matched controls, whether a single dose of Xyrem® causes changes in striatal binding of 11C-raclopride and 11C-DTBZ that would suggest altered activity of brain dopamine neurones.

Inclusion Criteria:

• current diagnosis of narcolepsy with cataplexy OR healthy control

Exclusion Criteria:

• use of any sedative hypnotics, tranquilizers, anticonvulsants, antihistamines (except non-sedating), benzodiazepines, clonidine or any medication known to affect dopamine at start of baseline period
• significant unstable or uncontrolled medical/psychiatric disease
• significant history of head trauma/surgery or seizure disorder
• radiation exposure exceeding 20mSv in last 12 months
• pregnancy
• substance abuse/dependence (including alcohol)
• have sleep apnea, or are shift workers
• on a sodium-restricted diet
• has ever taken Xyrem / sodium oxybate / GHB at any time
• claustrophobia
• metal implants / objects in the body that may interfere with MRI
• succinic semialdehyde dehydrogenase deficiency