Actions mean such things as dispersing the surface, clearing heat, draining dampness and so on. Indications mean specific patterns of illness treated with the medicinal. Viral infections are seen as a form of heat or fire in Chinese medicine, so antivirals are known to be cold by nature, as are antibiotics. Vitamin C, goldenseal and echinacea are also cold by nature. This is why vitamin C irritates the stomach at high doses.
Coldness leads to strong fixed-location pain.
Coldness in the stomach produces knotting pain. Cold also interferes with the ability of the stomach to maintain body temperature and thus digest properly. Protease inhibitors appear to share this unfortunate side effect mechanism, though with devastating effects compared to vitamin C's relatively innocuous ones. Nowhere have I read a formal Chinese medicine explanation of the energetics of protease inhibitors, so I will attempt a preliminary one of my own. Obviously PI's are cold by nature, probably bitter in taste, probably descending, enter the spleen, kidney, urinary bladder and perhaps liver, heart and large intestine channels, clear heat and kill viruses.