A client with amyotrophic lateral sclerosis (ALS) has been taking riluzole for two weeks. The nurse notes that the client remains weak with observable muscle atrophy. Which action should the nurse take?

Document the assessment findings in the electronic health record.

Explain that the medication takes several weeks to reverse symptoms.

Advise the client to schedule an appointment for liver function tests.

Withhold the medication until the healthcare provider is notified.