fosamax, the brand-name form of alendronate,is a prescription medication used to treat osteoporosis and paget's disease. it is alsoused to prevent osteoporosis in postmenopausal women. fosamax is in a class of medicationscalled bisphosphonates. these work by preventing bone breakdown and increasing bone density.fosamax comes in tablet and liquid forms. it is usually taken daily or weekly, dependingon the dose and form, on an empty stomach and with a full glass of water. some commonside effects are stomach pain, heartburn, and constipation. always take this medicationonly as prescribed. keep up to date with medication information by following rxwiki on your favoritesocial media platforms.