The weight-based heparin dosing nomogram compared with a "standard care" nomogram. A randomized controlled trial

Ann Intern Med. 1993 Nov 1;119(9):874-81. doi: 10.7326/0003-4819-119-9-199311010-00002.


Objective: To determine whether an intravenous heparin dosing nomogram based on body weight achieves therapeutic anticoagulation more rapidly than a "standard care" nomogram.

Design: Randomized controlled trial.

Setting: Two community teaching hospitals in Phoenix, Arizona, and Rochester, New York.

Participants: One hundred fifteen patients requiring intravenous heparin treatment for venous or arterial thromboembolism or for unstable angina.

Intervention: Patients were randomized to the weight-based nomogram (starting dose, 80 units/kg body weight bolus, 18 units/kg per hour infusion) or the standard care nomogram (starting dose, 5000-unit bolus, 1000 units per hour infusion). Activated partial thromboplastin time (APTT) values were monitored every 6 hours, and heparin dose adjustments were determined by the nomograms.

Measurements: Activated partial thromboplastin times were measured using a widely generalizable laboratory method. The primary outcomes were the time to exceed the therapeutic threshold (APTT > 1.5 times the control) and the time to achieve therapeutic range (APTT, 1.5 to 2.3 times the control). Bleeding complications and recurrent thromboembolism were also compared.

Results: Kaplan-Meier curves for the primary outcomes favored the weight-based nomogram (P < 0.001 for both). In the weight-based heparin group, 60 of 62 patients (97%) exceeded the therapeutic threshold within 24 hours, compared with 37 of 48 (77%) in the standard care group (P < 0.002). Only one major bleeding complication occurred (in a standard care patient). Recurrent thromboembolism was more frequent in the standard care group; relative risk, 5.0 (95% CI, 1.1 to 21.9).

Conclusions: The weight-based heparin nomogram is widely generalizable and has proved to be effective, safe, and superior to one based on standard practice.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angina, Unstable / blood
  • Angina, Unstable / drug therapy
  • Body Weight
  • Drug Monitoring / methods*
  • Female
  • Hemorrhage / chemically induced
  • Heparin / administration & dosage*
  • Heparin / adverse effects
  • Humans
  • Infusions, Intravenous
  • Injections, Intravenous
  • Male
  • Middle Aged
  • Partial Thromboplastin Time
  • Proportional Hazards Models
  • Prospective Studies
  • Recurrence
  • Regression Analysis
  • Thromboembolism / blood
  • Thromboembolism / drug therapy
  • Treatment Outcome


  • Heparin