Dabigatran etexilate is a direct thrombin inhibitor whose activity directly correlates with kidney function. There is a 6-fold increase in its exposure with creatinine clearance under 30 ml/min, and hence Stage 4 or 5 kidney disease (creatinine clearance < 30 ml/min) is a contraindication for its use. In patients with stage 3 kidney disease, especially with creatinine clearance between 30-50 ml/min, there's a 2.7-fold increase in its exposure and the product monograph recommends a reduced dose of 150 mg daily. So, assessment of renal function is important to adjust dosage. If your patient develops acute renal failure during therapy, dabigatran should be stopped. However, lethal side effects have been reported in France (Legrand et al, Arch Intern Med 2011) and recently the German publication Die Zeit reported 50 deaths from bleeding in patients with atrial fibrillation treated with dabigatran (Kaiser C. Pradaxa bleeding deaths raise concern. www.medpagetoday.com/Cardiology/Strokes/29411) and a report from NewZealand reported increased bleeding complications in the elderly (Harper et al, New Eng J Med March 2011).
Therefore, despite suggestions that dabigatran does not require monitoring of its effects during treatment, renal, hematologic and hepatic indices should be monitored before and after initiation of dabigatran until more experience is gained with this new drug, and especially in the elderly and those with chronic kidney disease.