Riluzole is a medication used to treat amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease. It is the only FDA-approved treatment for ALS and has been shown to prolong lifespan by a few months in people with ALS.
What is ALS?
ALS is a progressive neurodegenerative disease that affects nerve cells in the brain and spinal cord. It causes loss of muscle control and paralysis due to the death of motor neurons. ALS usually strikes people between the ages of 40 and 70 and the average survival time after diagnosis is 3 to 5 years.
How does riluzole work?
The mechanism by which riluzole exerts its therapeutic effects in ALS is not fully understood. However, research suggests that it blocks glutamate signaling in the brain and spinal cord. Glutamate is an excitatory neurotransmitter and excess glutamate is thought to contribute to motor neuron damage in ALS.
By inhibiting glutamate release, riluzole may reduce excitotoxicity and neuronal damage in ALS patients. It also appears to have neuroprotective effects by stabilizing voltage-gated sodium channels on motor neurons.
Clinical trials on riluzole
Several clinical trials have been conducted to evaluate the efficacy of riluzole in ALS:
- A 1996 study on 155 ALS patients found that 100 mg of riluzole per day extended median survival by 2-3 months compared to placebo.
- A larger study in 1998 on 959 ALS patients also showed that riluzole 100 mg/day increased median survival by 2-3 months.
- A 2012 meta-analysis of 4 high-quality studies demonstrated that riluzole extended median survival by about 3 months compared to placebo.
Though the increase in lifespan is modest, riluzole was the first drug to show any survival benefit in ALS. It remains the standard of care for treating ALS patients.
Riluzole dosage
Riluzole is administered orally in tablet form. The recommended dosage is 50 mg taken twice per day, every 12 hours. It should be taken on an empty stomach, at least 1 hour before or 2 hours after meals.
The initial dose is usually 25 mg twice per day for the first week, then increased to 50 mg twice per day thereafter. Taking riluzole with food can substantially reduce its absorption.
Side effects of riluzole
The most common side effects of riluzole (occurring in >10% of patients) include:
- Nausea
- Asthenia (weakness)
- Headache
- Dizziness
- Decreased lung function
Less common side effects (1-10% of patients) include:
- Vomiting
- Insomnia
- Somnolence
- Vertigo
- Circumoral paresthesia
- Hypertension
Rare but serious side effects include hepatotoxicity (liver damage), neutropenia (low white blood cell count), and interstitial lung disease. Patients on riluzole may require monitoring of liver enzymes and white blood cell counts.
Cost and availability of riluzole
The average wholesale price of riluzole is about $600 for a bottle of 60 50mg tablets. However, the out-of-pocket cost for patients depends on insurance coverage. In the US, riluzole is available as a generic drug and as the brand-name drug Rilutek.
Some programs that may help lower the cost of riluzole include:
- Medicare Part D and Medicare Advantage prescription drug coverage
- Medicaid coverage in some states
- Patient assistance programs from the manufacturer
- Non-profit organizations providing financial assistance for drugs
Talking to your health provider and insurance company about your medication costs can help identify ways to obtain riluzole at more affordable prices.
Who is prescribed riluzole?
Riluzole is approved by the FDA specifically for the treatment of ALS. It can be prescribed by neurologists or doctors who specialize in ALS to patients after they have been diagnosed with definite or probable ALS based on medical history, physical examination, and specialized testing. Riluzole is not a cure, but it can extend lifespan and prolong the time before a patient may need ventilation support.
Some key points about using riluzole for ALS patients:
- Riluzole should be started as early as possible after diagnosis for maximum benefit.
- It can be used in combination with other supportive treatments and medications for ALS.
- Patients should be monitored for side effects and drug interactions.
- It is safe to use riluzole long-term for the duration of ALS disease.
- Discontinuing riluzole is associated with more rapid progression of ALS.
Limitations of riluzole
While riluzole can extend survival in ALS, its effects are fairly modest. The major limitations of this drug include:
- It only prolongs median survival by 2-3 months on average.
- It does not reverse damage already done from ALS.
- It does not improve muscle strength or function in ALS patients.
- Up to 30% of patients may not respond to riluzole treatment.
- The high cost may limit accessibility for some patients.
For these reasons, riluzole is not a cure and ALS patients will still experience progression of disease even when taking this medication. However, it remains the best available pharmaceutical option for improving prognosis.
Future treatment options
Significant research is underway to find more effective drugs and therapies to treat ALS. Some promising experimental treatments include:
- Edaravone – a free radical scavenger that has shown modest benefits in a clinical trial
- Masitinib – a tyrosine kinase inhibitor that may slow ALS progression
- NurOwn – stem cell therapy using a patient’s own cells to regenerate motor neurons
- Brainstorm ALS – mesenchymal stem cell transplantation into the spinal cord
- Gene therapies – delivering healthy genes to repair defective ones causing ALS
Advances in understanding the genetics and biology of ALS is fueling drug development efforts. Combination therapy using riluzole plus an additional experimental drug may offer better outcomes in the future. Palliative treatments are also extending quality of life for ALS patients.
Conclusion
Riluzole is the first FDA-approved medication for ALS and has demonstrated a modest but significant survival benefit. Clinical trials show it can extend median lifespan by around 2-3 months. Though its effects are limited, riluzole remains an important treatment option to prolong survival and slow disease progression in ALS patients. Earlier initiation of therapy and new drugs on the horizon may further improve prognosis for ALS in the future.