Pradaxa – consider age and follow dose recommendations

In March, in collaboration with the Thrombosis Centre in Aalborg, the Danish Health and Medicines Authority published an evaluation of all adverse reaction reports in Danish Pharmacovigilance Update for the period 22 August 2011 up to and including 23 February 2012 in connection with a new indication (prevention of apoplexy in patients with non-valvular atrial fibrillation) for Pradaxa® (dabigatran etexilate).

With this announcement, we once more want to call attention to the development in consumption, reported adverse reactions, age and dose recommendations.

Since Pradaxa was introduced on 22 August 2011 and up until the end of 2011, 4,610 persons have redeemed at least one prescription for Pradaxa®, 45% of these being women, and 55% men. Age distribution: 19% under 65 years, 37% between 65-74 years and 43% were 75 years or above.

Within a period of about seven months, 22 cases of serious gastrointestinal tract bleeding have been reported. These adverse reactions were distributed on 17 patients. More than 50% of cases were observed in elderly patients.

The development in consumption shows a disturbing trend; where 65 women and 56 men over the age of 80 have been prescribed 150 mg Pradaxa capsules, see Table 1.

Some 10% of patients above 80 years are, in other words, being prescribed the highest Pradaxa strength, indicating that this group of patients receive too high a dose. In the age group 80 and above, the recommended daily dose for the prevention of apoplexy in patients with non-valvular atrial fibrillation is 220 mg administered as one 110 mg capsule twice daily. The same dose should be considered for patients aged 75-80 years with a low thromboembolic risk and a high risk of bleeding based on the doctor's individual assessment.

Table 1. Strength of prescribed Pradaxa capsules. Users aged 75+

The Danish Health and Medicines Authority takes a very serious view of the apparently wrong use and recommends doctors to follow the dose recommendations specified in the summary of product characteristics.

The adverse reactions reported and the development in consumption demonstrate that it is important to take the patient's age into consideration, to assess the patient's other risk factors for bleeding, e.g. gastrointestinal ulcer, and other medicines that affect haemostasis, e.g. clopidogrel, acetylsalicylic acid and NSAIDs.

It is also important to take into consideration the patient's renal function at treatment start and during treatment, as dabigatran is secreted through the kidneys, and Pradaxa is contraindicated in patients with severe renal impairment (CrCL <30 ml/min.).