From the Research
For a 65-year-old male with long-term RRMS on Natalizumab who is experiencing significant balance and gait impairment, I recommend adding dalfampridine (Ampyra) 10 mg twice daily, taken approximately 12 hours apart. This potassium channel blocker specifically addresses walking difficulties by improving nerve conduction in demyelinated axons, as supported by studies such as 1, which evaluated dalfampridine for the treatment of relapsing-remitting multiple sclerosis and found it to improve walking speed and patient-reported perceptions of walking in some patients. The patient should take the medication consistently, with or without food, and should expect to see benefits within 2-4 weeks if it's going to be effective. It's essential to monitor renal function before starting treatment, as dose adjustment is needed for patients with moderate to severe renal impairment, and the medication is contraindicated in patients with a history of seizures, as noted in 2 and 3. Common side effects include urinary tract infections, insomnia, dizziness, headache, and nausea. The effectiveness of dalfampridine should be evaluated after 4-8 weeks; if no improvement in walking speed or stability is observed, discontinuation should be considered. This medication works differently than Natalizumab, which prevents inflammatory cells from entering the central nervous system, making them complementary treatments that address different aspects of MS management, as discussed in 4 and 5. Key points to consider when prescribing dalfampridine include:
- Monitoring for side effects and adjusting the dose as needed
- Evaluating the effectiveness of the medication after 4-8 weeks
- Considering the patient's renal function and history of seizures before starting treatment
- Educating the patient on the proper use of the medication and potential interactions with other medications.