Cite Jump to ExpandCollapse LetterApril 24, 2026 Discovery of MK-5661, a Once-Daily Oral NaV1.8 Inhibitor for the Treatment of Pain Click to copy article linkArticle link copied! Christopher J. Bungard* Christopher J. Bungard Discovery Chemistry, Merck & Co., Inc., West Point, Pennsylvania 19486, United States *[email protected] Michael J. Breslin Michael J. Breslin Discovery Chemistry, Merck & Co., Inc., West Point, Pennsylvania 19486, United States Christopher W. Boyce Christopher W.