Three groups of drugs are used to reduce the stickiness of platelets, thus preventing platelets from clumping together to form platelet plugs. The anti-platelet drugs are most effective in preventing abnormal blood clots from forming in arteries (as opposed to veins). Aspirin and dipyridamoleâ (Aggrenox).
In order to react, colliding molecules must have a total kinetic energy equal to or greater than some minimum value [Figure 14.13(b)]. The minimum energy required to initiate a chemical reaction is called the activation energy, Ea. The value of Ea varies from reaction to reaction.
Energy of activation (EA) 1  amount of energy that reactants must absorb to start a chemical reaction. 2  can be thought of as an energy barrier. 3  since most reactions require energy to get started.  illustrated with jumping bean (JB) 1  analogy. solution for speeding up a reaction lies in enzymes.  protein molecules that serve as biological catalysts.