Despite the limitations of the published data, what literature was found in this review suggests that there is little justification for capping doses of LMW heparin. Most of the evidence reviewed here supports dosing based on total body weight. Others have drawn similar conclusions, whereas at least one group was less confident about drawing any conclusions, given the insufficiency of the data.
Whether doses of LMW heparin should be given as a single daily dose or divided into a twice-daily dose for obese patients is debatable. As well, obese patients with comorbidities that alter drug clearance have not been well studied. The most important group in this situation would be obese patients with renal insufficiency.
Very little information is available for patients weighing more than 150 kg, and we are unable to draw any firm conclusions about dosing of LMW heparins for such patients. Consideration should be given to using peak anti-Xa levels to assess the degree of anticoagulation. Another alternative would be to use standard IV unfractionated heparin with monitoring of activated partial thromboplastin time for this patient group. On the basis of the limited data in the literature, some clinicians cap the dose at a body weight of 150 kg and check anti-Xa levels if therapy is planned for more than 3 days. levitra plus
In conclusion, Canadian product monographs recommend that doses of LMW heparins be capped according to body weight, but the evidence supporting this practice is sparse and inconclusive. This dose-capping practice is inconsistent with LMW heparin management strategies used in other countries. Outcome data are conspicuously absent for obese patients with venous thromboembolism, and a large, prospective randomized study addressing this issue would be valuable. One advantage of the LMW heparins is consistent anticoagulation response with standardized weight-based regimens. Using a dose cap complicates therapy and has unclear effects on patient outcomes. Although only limited literature is available, most reports support dosing LMW heparins according to total body weight for patients weighing up to 150 kg.