This patient's dalfampridine (4-aminopyridine) should be discontinued. Dalfampridine is a voltage-gated potassium channel antagonist that can potentiate action potentials along demyelinated axons and is used in patients with multiple sclerosis (MS) for potassium channel blockade. This medication can improve lower extremity function and walking speed and endurance. Because of its mechanism of action, seizures have been reported as a rare, dose-dependent adverse effect of this medication. Dalfampridine is excreted through the kidneys and thus is contraindicated in patients with kidney disease because its resultant decreased clearance would significantly increase the seizure risk. For this reason, this medication should be discontinued in this patient.

Baclofen can alleviate the spasticity often associated with MS. There is no reason to discontinue the drug in this patient with acute kidney injury because no specific adverse effects of this drug due to kidney toxicity or related to kidney clearance have been reported. Dosing may have to be modified in patients with severe kidney failure, however.

Glatiramer acetate is a disease-modifying medication used in the treatment of MS to impede disease activity and prevent relapses. This drug has no known adverse effects on the kidneys due to poor clearance or direct toxicity.

Vitamin D supplementation is now suggested for all patients with MS to reduce the accumulation of new lesions on MRI. No adverse effects on kidney function or kidney clearance have been reported.