MHRA advises on anticoagulant dose adjustment in patients with renal impairment

By Chloe Harman on the 30 October 2019

Estimated glomerular filtration rate (eGFR) should not be used to adjust doses of direct-acting oral anticoagulants in patients with renal impairment, the MHRA has advised.

For most drugs and for most adult patients of average build and height, eGFR is an acceptable estimate of renal function.

Further information

View anticoagulant drug records MHRA Drug Safety Update MIMS Cardiology Clinic

However, use of eGFR to guide dosing of direct-acting oral anticoagulants is known to increase the risk of bleeding events as a consequence of overestimating renal function. In patients taking these drugs, the MHRA says creatinine clearance should be calculated using the Cockcroft-Gault formula to determine dosage adjustments.

Creatinine clearance should also be used to determine dosage adjustments for:

patients taking nephrotoxic drugs (such as vancomycin and amphotericin B)
elderly patients (aged 75 years and older)
patients at extremes of muscle mass (BMI < 18kg or > 40kg/m²)
patients taking medicines that are largely renally excreted and have a narrow therapeutic index (such as digoxin and sotalol)

Prescribers can quickly look up dose adjustments for direct-acting oral anticoagulants in renal impairment using the at-a-glance MIMS guide to NOAC dosages in non-valvular atrial fibrillation.

There are currently four direct-acting oral anticoagulants available in the UK: apixaban, dabigatran, edoxaban, and rivaroxaban.