Dabigatran: capsule anticoagulant, kidney checks and reversal

Dabigatran etexilate is an anticoagulant. The UK product information describes three main groups of use: preventing clots after some orthopaedic surgery, preventing stroke in atrial fibrillation, and treating and preventing venous thromboembolism, meaning clots in the veins.

Dosing differs for each purpose, and there are paediatric doses based on weight and age. Your prescriber sets yours, and the leaflet supplied with the pack describes how to take the capsules.

The SmPC points out that for stroke prevention in atrial fibrillation the capsule strength you receive is chosen for you, and that orthopaedic prevention is a limited course after surgery rather than a lifelong tablet. If you are not sure which of these applies to you, ask the pharmacist to explain the label, and keep your prescribed schedule even when you feel well.

The patient leaflet says the capsules must be swallowed whole with water, and they must not be opened. The leaflet also covers what to do about missed doses, surgery and storage, so keep it with your medicines.

You will be given an anticoagulant alert card. Carry it at all times, because staff in an emergency need to know you are on dabigatran.

The medicine is eliminated largely through the kidneys. The SmPC says it is contraindicated in severe kidney impairment, defined as creatinine clearance below 30ml/min, and in active bleeding or lesions with a high bleeding risk. Kidney function is assessed before and during treatment using the Cockcroft-Gault calculation rather than routine clotting tests.

Strong P-glycoprotein inhibitors such as ketoconazole must not be used with it. Tell your prescriber about every medicine you take.

P-glycoprotein inhibitors can sharply raise dabigatran levels. The SmPC names verapamil, amiodarone and quinidine as medicines that may need a dose adjustment. Rifampicin and other P-gp inducers should be avoided because they lower exposure.

Because this list is long and technical, ask the pharmacist to check each new prescription and over-the-counter purchase against dabigatran. That includes herbal products.

Bleeding is the main risk. Look out for unusual bruising, bleeding that does not stop, blood in urine or stools, black stools, vomiting blood or sudden severe headache. Seek urgent medical help if any of these occur.

For serious bleeding in adults, the SmPC says idarucizumab provides rapid reversal and haemodialysis can remove dabigatran. No reversal agent exists yet for children, according to the same document.

Animal studies showed reproductive toxicity. Women who could become pregnant should avoid pregnancy during treatment, and the SmPC states that breastfeeding should be discontinued while taking dabigatran.

If you become pregnant while on it, speak to your doctor straight away rather than stopping the capsules yourself. Suspected side effects can be reported to the MHRA Yellow Card scheme.

The leaflet also covers storage and what to do with unwanted capsules, and it describes how to handle perioperative care, so bring the leaflet and your alert card to any pre-operative appointment.