<b>Aim:&nbsp;</b>To analyze the prescription of low molecular weight heparins in hospitalized patients at the Clinica Biblica Hospital (private hospital in Costa Rica) based on the guidelines established by the American College of Chest Physicians (ACCP;2008). <b>Material and methods</b>: This study included 1651 hospitalized patients in the period from March to August 2010 who were treated with low molecular weight heparins, 250 patients were analyzed and randomly selected. A compilation of documents and information required for each patient for the analysis was made. <b>Results</b>: A total of 43% of the hospitalized patients used low molecular weight heparins (707 patients). In 91% of cases low molecular weight heparins were used with a prophylactic purpose. 2% of patients did not need to use prophylactic heparin therapy. In 90% of cases the dose was correct. 18% of cases required dose adjustments. In 80% of the patients had clinically relevant drug interactions, 4% of patients had some form of bleeding, where 2% of cases this effect was linked to the use of low molecular weight heparins. In 9% of cases in which LMWH were used as treatment were addressed in accordance with established guidelines. <b>Conclusion</b>: In the Hospital Clinica Biblica low molecular weight heparins were used according to the recommendations established by the guidelines of the ACCP despite the non-existence at the time of a hospital protocol. A pharmacotherapeutic analysis by the clinical pharmacist can provide important information to the medical doctor in order to take corrective and / or preventive actions associated with the correct use of medications. Make correct risk stratification and individualization of treatment facilitates proper implementation of drug therapy with low molecular weight heparins in this hospital where there is a high proportion of patients that may develop thromboembolic events.

trombosis venosa profunda; tromboprofilaxis; efectos secundarios; sangrados; Low molecular weight heparins; Drug utilization study; Deep vein thrombosis; thromboprophylaxis; side effects; bleeding