Which drug class would be prescribed to decrease clotting time?

Anticoagulants are the drug class specifically designed to decrease clotting time. Their primary function is to inhibit the formation of blood clots, which can prevent conditions such as deep vein thrombosis, pulmonary embolism, and stroke. By reducing the blood's ability to coagulate, anticoagulants allow for smoother blood flow and help in managing or preventing thrombotic disorders.

In contrast, antibiotics are used to treat bacterial infections, antihistamines are primarily utilized for allergy management by blocking histamine receptors, and antidepressants are aimed at treating mood disorders. Therefore, these other classes do not serve the purpose of affecting clotting time in the same way that anticoagulants do. This specific action of anticoagulants, in reducing clot formation and improving circulation, makes them the correct choice for the question regarding their role in decreasing clotting time.