Weaning before surgery
Stopping clopidogrel carries the risk of unintentional blood clots forming and so-called thromboembolic events such as heart attacks or strokes. However, since there is always a risk of bleeding during surgery, clopidogrel must in most cases be discontinued at least 5 days before surgery. For operations with a low risk of bleeding, the doctor treating the patient decides whether the blood-thinning therapy with clopidogrel should either be continued or replaced by another blood thinner (e.g. heparin) during the operation, or whether the intake of an anticoagulant should be completely discontinued. In any case, the patient should not discontinue clopidogrel on his own. Due to the increased risk of clot formation with serious consequences such as heart attack or stroke, the doctor should always be consulted.
Sneaking
In a consultation, the doctor will make recommendations on how best to discontinue clopidogrel. Usually, the intake of clopidogrel can be stopped immediately without having to reduce the dose. After 5 to 7 days after the final discontinuation of clopidogrel, the blood-thinning effect is reversed, as the previously inhibited platelets have been replaced by new ones. The new platelets can continue to function normally. Since in very rare cases a so-called “rebound phenomenon” has been observed – i.e. there was an increased risk of clot formation after discontinuing clopidogrel – discontinuing clopidogrel should be done precisely in consultation with a physician.
Half-life
Clopidogrel binds to a site on the platelets to which, in a physiological sense, ADP would normally bind. The blocking of this receptor by clopidogrel is irreversible. This means that clopidogrel remains at the binding site until the platelet dies.
As a result, platelets are impaired throughout their lives and are no longer capable of clotting. However, platelets only survive 8-12 days. Therefore, the blood’s ability to clot increases again with the formation of new platelets.
The half-life of clopidogrel is 6 hours. This means that 6 hours after taking clopidogrel, 50% of the active substance is still present in the blood and can therefore inhibit newly formed platelets.
