There are also many drug interactions . Patients must read in detail the enclosed data sheet(s) of the medicine. For example, the azole antifungals such as ketoconazole or itraconazole can be both substrates and inhibitors of the P-glycoprotein , which (among other functions) excretes toxins and drugs into the intestines.  Azole antifungals also are both substrates and inhibitors of the cytochrome P450 family CYP3A4 ,  causing increased concentration when administering, for example, calcium channel blockers , immunosuppressants , chemotherapeutic drugs , benzodiazepines , tricyclic antidepressants , macrolides and SSRIs .
Salicylic acid (SA) is a phenolic phytohormone and is found in plants with roles in plant growth and development, photosynthesis , transpiration , ion uptake and transport.  SA is involved in endogenous signaling, mediating in plant defense against pathogens .  It plays a role in the resistance to pathogens by inducing the production of pathogenesis-related proteins .  It is involved in the systemic acquired resistance in which a pathogenic attack on one part of the plant induces resistance in other parts. The signal can also move to nearby plants by salicylic acid being converted to the volatile ester, methyl salicylate .