MedMark Treatment Centers Merrillville is an addiction treatment center located at 8500 Broadway Ste. H, Merrillville, IN 46410. The center offers support and services to individuals seeking recovery from substance use disorders. With a rating of 3.8 based on 29 reviews, MedMark is open Monday through Friday from 4:45 AM to 11:30 AM and Saturday from 6 AM to 10 AM. For more information, visit their website at medmark.com or call +1 219-472-1580.