This is an early phase safety evaluation of the use of oral extended release (OER) glibenclamide, which is otherwise known as glyburide, for use as a treatment for neurologic pain in people with multiple sclerosis. Patients will receive medication to assess safety and tolerability.

This is a 2-stage pilot study of the pharmacodynamics and clinical effects of OER glibenclamide in MS patients with neuropathic pain. This pilot study will include 10 subjects. In Stage 1 of the study, which will last 5 days, unblinded subjects will take test-drug twice daily each day and participate in PK determinations. Successful completion of this Stage will establish the ability of a subject to safely tolerate the test-drug. In Stage 2 of the Study, which will last 3 months, blinded subjects who have demonstrated the ability to safely tolerate the test-drug will be asked to evaluate its clinical efficacy specifically with regard to neuropathic pain. By using a 3-block/on-off design with blinding, each subject will serve as their own control during the Stage-2 efficacy part of the study.

Inclusion Criteria:

1. Age 18-65
2. Diagnosis of multiple sclerosis per the 2017 Revised McDonald Criteria
3. Score of ≥ 19 on the painDETECT questionnaire

Exclusion Criteria:

1. Severe renal disorder from the patient's history (e.g., dialysis) or eGFR of < 30 ml/min.1.73m2
2. Severe liver disease, or ALT > 3 times upper limit of normal or bilirubin >2 times normal
3. Acute ST elevation myocardial infarction, and/or acute decompensated heart failure, and/or QTc > 520 ms, and/or known history of cardiac arrest (PEA, VT, VF, asystole), and/or admission for an acute coronary syndrome, myocardial infarction, or coronary intervention within the past 3 months
4. T2DM treated with insulin or oral medication
5. Blood glucose < 55 mg/dL at enrollment or immediately prior to administration of study drug or a clinically significant history of hypoglycemia.
6. Known sulfonylurea treatment within 7 days. Sulfonylureas include glyburide/glibenclamide (Diabeta, Glynase); glyburide plus metformin (Glucovance); glimepiride (Amaryl); repaglinide (Prandin); nateglinide (Starlix); glipizide (Glucotrol, GlibeneseR, MinodiabR); gliclazide (DiamicronR); tolbutamide (Orinase, Tolinase); glibornuride (Glutril)
7. Known allergy to sulfa or specific allergy to sulfonylurea drugs
8. Known G6PD enzyme deficiency
9. Pregnancy. Women must be either postmenopausal, permanently sterilized or, if ≤50 years old must have a negative test for pregnancy obtained before enrollment
10. Breast-feeding women who do not agree to stop breastfeeding during Study Drug infusion and for 7 days following the end of Study Drug infusion

In stage 2, medication will be either placebo or treatment, blinded in appearance. Investigators will not be aware of placebo/treatment assignment.