Table 2.

Progressive steps to perform when therapeutic drug monitoring is not available

1.Check compliance 2.Stop interacting drugs, if possible 3.Use more bioavailable formulations (e.g., switch to super bioavailability [SUBA] for itraconazole or switch to gastro-resistant tablet formulations for posaconazole instead of suspensions) 4.Stop histamine-2 inhibitors or proton-pump inhibitors 5.Use fat-rich food, such as ice cream, cheese, and other dairy products, when using posaconazole suspension 6.Switch to intravenous formulations, if possible 7.Escalate dose, change drug, or add another agent