Riluzole-induced lung injury in two patients with amyotrophic lateral sclerosis

Treatment continuity of amyotrophic lateral sclerosis with available riluzole formulations: state of the art and current challenges in a 'real-world' setting

Amyotrophic lateral sclerosis (ALS) is a rare multisystem neurodegenerative disease leading to death due to respiratory failure. Riluzole was the first disease modifying treatment approved in ALS. Randomized clinical trials showed a significant benefit of riluzole on survival in the months following randomization, with a good safety profile. 'Real-world' studies suggested that the survival benefit of riluzole is substantially greater, with an extended survival ranging between 6 and 19 months. The main limiting associated adverse effects of riluzole are non-severe gastrointestinal complications and an elevation of liver enzymes, observed in 10% of patients. While different classes of drugs have been approved in some countries, riluzole remains the gold standard of therapy. Dysphagia induced by ALS is a major challenge for food intake and riluzole administration. Tablet crushing is associated with a loss of drug intake and a risk of powder aspiration, which jeopardizes the benefits of riluzole. Riluzole oral suspension (ROS) and oral film (ROF) allow riluzole intake in patients with dysphagia. Both formulations are bioequivalent to riluzole tablets with a good safety profile albeit transient oral hypoaesthesia. In case of severe dysphagia, ROS can be used with percutaneous endoscopic gastrostomy. ROF, the last approved formulation, requires low swallowing capacities and may contribute to maintain the efficacy of riluzole when tablets are inadequate according to patient's status and/or preferences. To optimize treatment continuity in newly diagnosed patients, the expected psychological impact of formulation switching that may be perceived as the sign of disease progression should be anticipated.

Real-world safety profile of riluzole: a systematic analysis of data from the FAERS database and case reports

BACKGROUND

The study aims to obtain the safety profile of riluzole in the real world and provide reference for clinical drug applications.

RESEARCH DESIGN AND METHODS

Proportional reporting ratio (PRR) was used to detect riluzole adverse drug reactions (ADRs) from the data between the first quarter of 2004 and the third quarter of 2022 in the FDA adverse event reporting system database (FAERS). Case reports of riluzole published in PubMed, Embase, and Web of Science before November 2022 were reviewed, and patient's data were extracted.

RESULTS

FAERS analysis identified 86 ADRs. Gastrointestinal system disorders and respiratory, thoracic, and mediastinal disorders account for 12 of the top 20 most frequent ADRs. Similarly, 9 of the 20 highest PRR ADRs were gastrointestinal system disorders and respiratory, thoracic, and mediastinal disorders. Twenty-two published riluzole-associated cases were identified in the literature. Respiratory, thoracic, and mediastinal disorders were the most commonly reported cases (n = 9), followed by gastrointestinal disorders, pancreatitis (n = 5).

CONCLUSIONS

Strong ADRs between riluzole and pancreatitis were identified, which reminds clinicians to monitor patients carefully. For patients with respiratory symptoms, clinicians should pay attention to distinguish the cause of their occurrence, and take appropriate measures. Beware that riluzole may increase the risk of inflammatory reactions and inappropriate vasopressin secretion and hyponatremia due to respiratory failure.

Riluzole for the treatment of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease caused by the death of motor neurons. Riluzole is a benzothiazole derivative that blocks glutamatergic neurotransmission in the CNS, which is thought to exert neuroprotective effects. Riluzole was approved by the US FDA in 1995 as the first drug to treat ALS. Although riluzole is generally safe and well tolerated in clinical practice, its efficacy in ALS is modest, prolonging tracheostomy-free survival by only 2-3 months. In this article, we will first provide an overview of the ALS field, followed by a discussion of riluzole regarding its physical properties; pharmacology; clinical efficacy in ALS; safety and tolerability; and recommended administration.

Riluzole-induced interstitial lung disease is a rare and potentially life-threatening adverse event successfully treated with high-dose steroid therapy: Case reports and review of the literature

Riluzole (RZ)-induced interstitial lung disease (RZ-ILD) is a rare and potentially life-threatening adverse event in amyotrophic lateral sclerosis (ALS) patients, which is rarely reported. Therefore, the optimal treatment for RZ-ILD is unclear. We describe herein three Japanese cases of ALS complicated with RZ-ILD, of which two were successfully treated with high-dose steroid therapy. In our all ALS cases with RZ-ILD, the duration of RZ exposure until RZ-ILD onset was within 2 months. All three cases showed respiratory symptoms, dorsal predominant ground-glass opacities by imaging analysis, and abnormal laboratory findings associated with interstitial lung diseases, such as Krebs von den Lungen-6 and surfactant protein-D. Intravenous high-dose steroid therapy together with the discontinuation of RZ in two cases with respiratory symptoms markedly ameliorated their symptoms and abnormal findings of RZ-ILD. One case showed mild respiratory symptoms compared with the others and recovered after the withdrawal of RZ only. According to previous case reports and our cases, RZ-ILD may develop 2 months after initiating RZ and exacerbate respiratory symptoms rapidly in ALS patients with severe respiratory muscle involvement or complicating aspiration pneumonia. Transient high-dose steroid therapy in addition to discontinuation of RZ might be a good therapeutic option for RZ-ILD.

Interstitial pneumonia and other adverse events in riluzole-administered amyotrophic lateral sclerosis patients: a retrospective observational study

Background

Riluzole is the only approved oral drug for amyotrophic lateral sclerosis (ALS). We performed a retrospective study including ALS patients treated with riluzole, focusing on adverse events.

Methods

Patients diagnosed with ALS according to the revised El Escorial criteria (World Federation of Neurology) in our center and who were administered 50 mg oral riluzole twice daily between January 2011 and September 2017 and followed up for at least 6 months from treatment initiation or until death were included. Data regarding sex, age, disease type, initial symptoms, biochemical analyses performed before and after riluzole administration, and medical history were collected. In case of withdrawal, cause of discontinuation and durations of disease and drug administration were recorded.

Results

A total of 92 cases were enrolled. Riluzole administration was discontinued in 20 cases (21.7%). The most frequent reason for discontinuation was elevated liver enzymes (n = 5, 5.4%), followed interstitial pneumonia (IP), nausea and appetite loss, dizziness, general malaise, tongue paresthesia, and urinary urgency. In two cases, administration was discontinued primarily because of progression of bulbar palsy. All adverse events occurred within 6 months from treatment initiation and improved soon after its discontinuation. Three IP cases developed severe respiratory failure and required steroid treatment.

Conclusion

Riluzole administration was discontinued in 20 cases among total of 92 cases. Careful follow-up is important for the first six months after the initiation of riluzole administration, including through interviews, chemical analyses, and chest X-rays, as required.

[Riluzole-induced interstitial pneumonia in a case with amyotrophic lateral sclerosis]

A 74-year-old woman was clinically diagnosed with possible amyotrophic lateral sclerosis (ALS) and was administered 100 mg/day of riluzole. After 2 months, she developed dyspnea and experienced gradual difficulty walking. Chest computed tomography revealed ground-glass opacity and consolidation in the lower lobes of both the lungs, thereby suggesting a diagnosis of interstitial pneumonia. Because the condition was suspected to be drug-induced, riluzole administration was discontinued and steroid (methylprednisolone) pulse therapy (1,000 mg/day, 3 days) was started. Her symptoms and radiological findings improved immediately. At 16 months later, she wanted to take riluzole again. She had the similar interstitial pneumonia on the 4(th) day of the re-administration. Drug (riluzole)-induced lymphocyte stimulation tests (DLST) were negative two times. The symptoms of interstitial pneumonia, a rare adverse effect of riluzole, are very similar to worsening symptoms of ALS; therefore, patients with ALS receiving riluzole therapy should be carefully monitored.