Background Major bleeding complications with LMWH treatment have been reported both in clinical studies and during post-marketing surveillance. Monitoring of anti-factor Xa activity is recommended in special populations treated with low molecular weight heparins (LMWH).

Purpose To evaluate the effectiveness and safety of LMWH administration as prophylaxis and treatment of venous thromboembolism and acute coronary syndromes in selected patients.

Material and methods Prospective, descriptive study included patients with renal impairment, obese or elderly patients treated with LMWH over five months (January–May 2014). Study variables collected: sex, age, indication and doses of enoxaparin, anti-factor Xa, creatinine and platelets. The data were obtained from clinical records and prescriptions.

Results Anti-factor Xa was studied in 62 patients, 39 men (63%) and 23 women (37%) with a mean age of 67 years (32–90). 40% of patients had renal failure, 45% obesity and 15% were elderly patients.

The treatment dose of LMWH is 1 mg/kg/12 h (including for obese patients) but in renal impairment 1 mg/kg/24 h is recommended and in elderly patients, 1.5 mg/kg/24 h. 58 patients (93.5%) received therapeutic doses. There were 34.5% low doses, 51.7% correct doses and 13.8% high doses, and the average of anti-factor Xa was 0.3 IU/ml, 0.74 IU/ml and 1.5 IU/ml respectively.

The prophylactic dose is 40 mg/24 h but in renal impairment 20 mg/24 h is recommended and in obese patients, 60 mg/24 h. 4 patients (6.5%) received prophylactic doses. There were 25% low doses and 75% correct doses, and the average of anti-factor Xa was 0.6 IU/ml and 0.26 IU/ml, respectively. Our pharmaceutical interventions were to increase or reduce and repeat the control. All our recommendations were approved.

Regarding safety, there were six thrombocytopenic (9.7%) patients and no bleeding.

Conclusion Anticoagulation monitoring optimises the effectiveness in patients with special requirements, such as patients with renal failure, obesity and elderly patients. 60% of prescriptions were for low doses, therefore the Pharmacy Service proposed making a protocol for coagulation.

References and/or Acknowledgements

1. Br J Clin Pharmacol 2007;64:428–3

2. Ann Pharmacother 2009;43:1064–83

References and/or AcknowledgementsNo conflict of interest.