Some neurones in the brain and spinal cord release an amino acid, called glutamate, to carry signals to other neurones. Glutamate is released at the synaptic junction where two neurones meet. If too much glutamate is released by the neurone sending a signal, it can over-stimulate the neurone receiving the signal. This is called glutamate excitotoxicity. Riluzole is an anti-glutamate medication that appears to block the release of glutamate from neurones. Riluzole may also exert some effects on MND through other mechanisms but this has yet to be firmly established.
Motor neurone disease is a general term applying to progressive, degenerative disorders affecting the motor neurones. Motor neurones carry signals from the brain to the muscles. In people with motor neurone disease, the motor neurones deteriorate and can no longer carry these signals.
Researchers have found that glutamate excitotoxicity may accumulate to harmful levels and contribute to motor neurone deterioration.1 The effect of riluzole, an anti-glutamate medication, has been investigated on people with the following forms of motor neurone disease:
Medical literature about riluzole generally uses the term amyotrophic lateral sclerosis (ALS) as an umbrella term to include progressive bulbar palsy (PBP). This is because there is:
Riluzole is manufactured under the names Rilutek™ and APO-Riluzole. In Australia riluzole is available for eligible people at a subsidised price on the Pharmaceutical Benefits Scheme (PBS) under an authority prescription. To get your first authority prescription for riluzole you must be diagnosed with the ALS form (including PBP) of MND by a neurologist, have had the disease for five years or less and meet several other criteria. Your doctor needs to provide your date of diagnosis and information about your forced vital capacity* with the first application. Subsequent prescriptions may be issued by your general practitioner.
Teglutik® (riluzole) a liquid formulation (for ease of swallowing or use via PEG tube) of riluzole, distributed by Seqirus (Australia) Pty Ltd, was listed on the PBS in April 2019 under the same prescribing conditions as Rilutek™ and APO-Riluzole.
In their analysis of the results of four double-blind randomised controlled trials, involving 1477 people with the ALS form (including PBP) of motor neurone disease, Miller et al. (2012) found that taking 100 mg of riluzole daily:
One of the trials included in the analysis only enrolled people older than 75 years or who had the disease for more than five years. The inclusion of this trial decreased median survival time.
Several riluzole studies were not included in the analysis because they were not double-blind randomised controlled trials (the best evidence). These excluded studies reported a median survival prolongation ranging from 6 to 21 months. It is not known what other factors, such as other interventions and stage of the disease, might have influenced the results of these excluded studies.1
More recently a review undertaken by Andrews et al. (2020) suggests that taking riluzole may be more effective than first thought.2 A review of 15 population studies undertaken by clinicians treating people with ALS/MND found that people who took riluzole, when compared with those who didn’t, generally lived longer, anywhere between 6 to 19 months longer.2
The review, which was of real world evidence studies, provides additional insights on the effectiveness of riluzole as an important treatment option for people living with ALS. Additionally, the review found that in several population studies the greatest benefit of riluzole occurs early in the course of disease thereby providing evidence both for early and prolonged riluzole therapy.2
All trials of riluzole published in the medical literature have only allowed people diagnosed with the ALS form (including PBP) of motor neurone disease to participate. There is strong clinical support for the use of riluzole in other forms of motor neurone disease .3 However, in Australia, subsidised PBS prescriptions for riluzole are limited as a treatment for the ALS (including PBP) forms of motor neurone disease alone.4
Adverse effects from riluzole are relatively minor and, for the most part, reversible after stopping the drug.1 The most common adverse effects are fatigue and nausea. Riluzole affects liver function and should be prescribed with care in people who have pre-existing problems with liver function.
Regular blood testing to monitor liver function (every month for three months, then every three months for a further nine months and annually thereafter) is recommended for people taking riluzole.3
Your neurologist can offer advice about riluzole. If you have been refused access to riluzole under the PBS and think you are eligible, talk with another neurologist or contact your MND clinic. Contact your local MND Association for more information.