Clinical studies have indicated that the time period between clinical and mycological cure may vary. It is therefore advised to minimize the risk of re-infection or spread of infection by keeping healthy animals separate from animals that are being treated. Cleansing and disinfection of the environment with appropriate products is highly recommended – especially in cases of multiple cat infections. In exceptional cases, a prolonged time between clinical and mycological cure may be observed. In such cases, a repeated treatment may be necessary. Some cases of dermatophytosis may never be completely cured.

In human medicine, interactions between itraconazole and certain other drugs have been described, resulting from interactions with cytochrome P450 3A4 (CYP3A4) and P-glycoproteins (PgP). This may result in increased plasma concentrations of e.g. oral midazolam, cyclosporin, digoxin, chloramphenicol, ivermectin, or methylprednisolone. The increased plasma levels can prolong the duration of effects as well as side effects. Itraconazole may also increase the serum level of oral anti-diabetic agents, which may result in hypoglycaemia.

On the other hand, some drugs e.g. barbiturates or phenytoin, can increase the rate of metabolism of itraconazole, resulting in a decreased bioavailability, hence a decreased efficacy. As itraconazole requires an acidic environment for maximal absorption, antacids cause a marked reduction in absorption. Concomitant use of erythromycin can increase the plasma concentration of itraconazole. Interactions in humans between itraconazole and calcium antagonists have also been reported. These drugs might have additive negative inotropic effects to the heart.

It is not known to what extent these interactions are relevant for cats, but in the absence of data, co-administration of Itrafungol and these drugs should be avoided.