Now that the patient knows the clinical difference between better and worse, if she ever feels worse again, she can take another dose of T4 (PRN similar side effects or decreased symptom resolution). If she doesn’t feel worse again, she shouldn’t take it because it goes against what we’re trying to accomplish. On a certain level of T3, if the patient ends up needing to take the T4 more than once, it commonly will be needed in a recurring interval of time (e.g. every 3 days, every 5 days, every 7days). Also, so long as the patient remains on that level of T3, the amount of T4 that is effective as a test dose shouldn’t change. But if a patient is on a higher dose of T3, it may be necessary to increase the T4 test dose in a roughly proportionate manner (p132).