Prescribing and monitoring of riluzole in amyotrophic lateral sclerosis: a retrospective cohort study from Health New Zealand - Te Whatu Ora Waitaha Canterbury.

AIM: This retrospective cohort study assessed adherence to the Motor Neurone Disease New Zealand best practice guidelines and Pharmac Special Authority criteria for riluzole in a Canterbury-based amyotrophic lateral sclerosis (ALS) cohort. Secondary objectives included reasons for not prescribing, side effects and treatment initiation relative to diagnosis. METHOD: A retrospective cohort study was conducted using the Christchurch Hospital respiratory department's ALS database. Patients diagnosed between January 2020 and November 2024 were included. Electronic health records and Special Authority records were reviewed. Patients with incomplete data or non-motor neurone disease (MND) diagnoses were excluded. RESULTS: Of 115 patients, 69 (60%) were prescribed riluzole. Less than 45% of patients had baseline blood tests, and pre-treatment spirometry was completed in 70% of patients. Delays in prescribing improved rates of baseline spirometry, but not blood test completion. Ongoing monitoring was poor, with less than 60% of patients completing recommended tests across all time points. Eight patients (11.6%) reported side effects, and three discontinued treatment following alanine aminotransferase derangement. CONCLUSION: Adherence to recommended monitoring and Special Authority criteria for riluzole was inconsistent in this cohort. In the context of emerging evidence supporting broader survival benefit and reduced drug cost, further evaluation of current Special Authority prescribing criteria may be warranted.