From the FDA Drug Label
Riluzole tablets is indicated for the treatment of amyotrophic lateral sclerosis (ALS) The efficacy of riluzole tablets was demonstrated in two studies (Study 1 and 2) that evaluated riluzole tablets 50 mg twice daily in patients with amyotrophic lateral sclerosis (ALS).
There may be a role for empiric treatment with Riluzole in a patient with presumed Amyotrophic Lateral Sclerosis (ALS) based on symptoms, but without Electromyography (EMG) confirmation, who is rapidly weakening.
- The FDA drug label for Riluzole indicates that it is used for the treatment of ALS, but it does not provide guidance on the use of Riluzole in patients without a definitive diagnosis of ALS.
- Key points to consider:
- Riluzole has been shown to improve survival in patients with ALS.
- The patient's rapid weakening may indicate a need for prompt treatment.
- However, the diagnosis of ALS has not been confirmed by EMG, which is a crucial diagnostic tool.
- Given the potential benefits of Riluzole in ALS treatment, and the patient's rapid decline, a conservative clinical decision would be to consider empiric treatment with Riluzole while awaiting EMG confirmation, but this should be done with caution and careful consideration of the potential risks and benefits 1, 1.
From the Research
Empiric treatment with Riluzole is appropriate for a patient with presumed ALS who is rapidly weakening, even without EMG confirmation. The standard dose is 50 mg twice daily, taken on an empty stomach (at least 1 hour before or 2 hours after meals) 2. While EMG testing is important for definitive diagnosis, delaying treatment in a rapidly progressing case may miss the window where Riluzole offers the most benefit. Riluzole works by reducing glutamate excitotoxicity in motor neurons, potentially extending survival by 2-3 months on average 3, 2. Patients should be monitored for side effects including elevated liver enzymes (check ALT/AST at baseline, monthly for 3 months, then quarterly), nausea, fatigue, and dizziness. Some studies suggest that Riluzole may have a more significant extension of survival in real-world evidence, with improvements in median survival times of more than 19 months reported in the overall ALS patient population 3. However, the exact mechanisms of action and the clinical efficiency of Riluzole are still being researched, with some studies indicating that it may exert neuroprotective effects by blocking glutamatergic neurotransmission in the CNS 2. Additionally, Riluzole has been shown to slow the progression of ALS and improve survival in patients with disease of bulbar onset 4. While initiating Riluzole, continue pursuing definitive diagnosis through neurology consultation and appropriate testing. The medication is not a cure but may slow disease progression, and early intervention is generally more beneficial than delayed treatment in this progressive, fatal condition. It's also important to note that Riluzole displays hormetic biphasic dose responses, which may have implications for research and clinical practice 5. Key points to consider when treating a patient with presumed ALS include:
- Initiating empiric treatment with Riluzole as soon as possible
- Monitoring for side effects and adjusting the treatment plan as needed
- Pursuing definitive diagnosis through neurology consultation and appropriate testing
- Considering the potential benefits and limitations of Riluzole treatment in the context of the patient's individual condition and progression of the disease.