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.
The activation energy and rate of a reaction are related by the equation k=Aexp(âEa/RT), where k is the rate constant, A is a temperature-independent constant (often called the frequency factor), exp is the function ex, Ea is the activation energy, R is the universal gas constant, and T is the temperature.