You are here: MEDICA Portal. Our Topics in 2009. Topic of the Month March: Blood. Prevention.
Pills Instead of Injection
Hope for an alternative to heparin
injections; © SXC
First it is the nurse who gives injections to the patient. Continuing the treatment with heparin at home the patient has to do this alone. For many people this is a problem and they decide to end the treatment. The consequence is an increased risk of thrombosis. It does not have to be this way though. Two new drugs were introduced onto the market in Germany last year.
However, these drugs to prevent blood clots are only used after surgery on knee and hip joint at the moment because the pills were tested only in these patients. “After such surgery the risk of developing thrombosis is very high because the leg must be immobilised completely”, explains Almut Tempka, leading physician at the section rehabilitation of the clinic of orthopaedics of the Charité Berlin. The prevention of blood clots has to continue some weeks after the intervention. “For the patient it is more convenient to take a pill than to give himself an injection into the belly”, Tempka says.
Different point of action than heparin
The new drugs block the enzyme thrombin which is responsible for the blood coagulation. With this mechanism the drugs have another point of action in the coagulation cascade than heparin. Heparin thins the blood by strengthening the effect of the enzyme antithrombin. But some people have a deficiency of antithrombin and heparin only helps them in a very high dose. For these patients the new pills could be an alternative.
Up to now, elevated liver values were not found in correlation with taking these drugs. Such hightened values were observed, however, in a similar compound which was licensed in 2004. Because of this side effect the drug was taken away from the market two years later. “But the idea of a pill was very good”, says Tempka. It remains to be seen if the new drugs stand the test on the market. So far, it is used only in few hospitals. “The study results are promising but data to long-term effects do not exist”, Tempka explains.
„The pills would be a breakthrough if they could also replace other coagulation-inhibiting drugs”, says Professor Hanno Riess from the clinic for internal medicine with focus on haematology and oncology at the Charité Berlin. Patients with atrial fibrillation or a risk of developing thrombosis often have to take coagulation-inhibiting drugs lifelong. These patients have their blood values checked by a doctor regularly in order to dose the drugs in the right way. Such checkups would not be necessary by taking the new drugs because they take hold in another way. “First studies on patients with atrial fibrillation are conducted at the moment”, Riess added.