The European Medicines Agency completed a safety review of strontium ranelate, a drug available by prescription only in Europe at a dose of 680 mg per day and used to treat osteoporosis that is considered severe due to the high risk of fracture. Analysis demonstrated that the increased risk of heart and circulatory effects was only significant in patients with a current or past history of heart and circulatory problems. Health Canada started its safety review because the risk of heart and circulatory side effects is a serious health issue, and because strontium is found in licensed natural health products as strontium salts, including strontium citrate, strontium lactate, and strontium gluconate.