Evaluation of warfarin dosing by pharmacists for elderly medical in-patients

Pharm World Sci. 2004 Aug;26(4):232-7. doi: 10.1023/b:phar.0000035885.00408.9e.


Objective: To compare the effectiveness of pharmacists dosing warfarin for in-patients, in comparison to that of junior doctors, in order to establish the value of a pharmacist-controlled in-patient anti-coagulation service.

Setting: Brighton and Sussex University Hospitals NHS Trust (BSUH).

Method: Two wards at Brighton General Hospital were under pharmacist-control of warfarin dosing and three wards remained under the care of doctors. Data was collected for 11 months and a total of 33 patients were recruited into each arm.

Results: Pharmacists prescribed more appropriate loading and maintenance doses (according to the Trust's Prescribing Guidelines) compared to doctors. This resulted in more patients reaching their target INR sooner. Documentation of indication, duration of treatment and target INR was also much improved compared to medical staff. However, more patients (73%) in the doctors' group were within range on discharge and at the out-patient clinic (79%), compared to the pharmacists (68% & 61% respectively). This could not be explained entirely. Significantly fewer patients dosed by pharmacists had episodes of over or under anti-coagulation (91% vs 67%) and fewer INR tests were requested (2.3/patient/week) compared to those dosed by doctors (2.7). Patients under the control of pharmacists also had fewer adverse events (6% vs 12%). One major GI bleed occurred in the doctors' group.

Conclusion: Pharmacist dosing of warfarin for in-patients had a beneficial effect on most aspects of anti- coagulation control. This study therefore provides further evidence to support the extended role pharmacists can play with the benefit of reducing risk, junior doctors' hours and improving patient care.

Publication types

  • Comparative Study
  • Evaluation Study

MeSH terms

  • Aged
  • Attitude of Health Personnel
  • Drug Administration Schedule
  • Drug Therapy / methods*
  • Guideline Adherence
  • Humans
  • Injections
  • Inpatients*
  • International Normalized Ratio / methods
  • International Normalized Ratio / trends
  • Medical Staff, Hospital / ethics
  • Medication Errors
  • Outpatients
  • Pharmacists / ethics
  • Practice Guidelines as Topic / standards
  • Time Factors
  • Treatment Outcome
  • United Kingdom
  • Warfarin / administration & dosage*
  • Warfarin / adverse effects


  • Warfarin