Fragmin (dalteparin) is an anticoagulant (blood thinner), a type of heparin indicated to prevent ischemic complications in unstable angina and non-Q-wave myocardial infarction, when concurrently administered with aspirin therapy. Fragmin is also used for the prevention of deep vein thrombosis in certain patients.Side effects of Fragmin include easy bruising or bleeding, or pain, redness, irritation, or swelling where the medicine was injected.Fragmin is available in single-dose, prefilled syringes preassembled with a needle guard device, and multiple-dose vials.able 5 summarizes major bleeding reactions that occurred with FRAGMIN, heparin, and placebo in clinical trials of unstable angina and non-Q-wave myocardial infarction. Table 5: Major Bleeding Reactions in Unstable Angina and Non-Q-Wave Myocardial Infarction.