Pentucket Medical - RiverWalk Get Directions Services At This Location: 500 Merrimack Street Lawrence, MA, 01843 Hours Please call 978-557-8900 for hours. Phone 978-557-8900 Find A Doctor Emily Liu Endocrinology Pentucket Medical View Bio Karen Mello Infectious Disease Pentucket Medical View Bio Sangeeta Nadkarni Nephrology Pentucket Medical.