Which two substances are commonly used to dissolve blood clots?

Urokinase and streptokinase are both fibrinolytic agents specifically designed to dissolve blood clots. They work by activating plasminogen, which converts into plasmin, the enzyme that breaks down fibrin, the main component of blood clots. This process is crucial in treating conditions such as myocardial infarctions (heart attacks) and pulmonary embolisms, where rapid dissolution of clots can be life-saving.

Other options provided are not primarily used for dissolving existing clots. Warfarin and heparin are anticoagulants that prevent new clot formation rather than directly dissolving existing clots. Aspirin and ibuprofen are analgesics and anti-inflammatory medications that do not dissolve clots; while aspirin can inhibit platelet aggregation, it does not have thrombolytic properties. Clopidogrel is an antiplatelet medication, which also prevents clot formation, and alteplase is actually a thrombolytic but is paired with clopidogrel in the answer option, which does not align with the requirement for two substances specifically known for dissolving clots. Thus, the pairing of urokinase and streptokinase stands out as the correct choice for their specific role in thrombolysis.