Eltrombopag is a potent iron chelator that can cause or worsen iron deficiency. In ITP patients with existing iron deficiency, alternative TPO receptor agonists like avatrombopag or romiplostim, which do not chelate iron, should be used instead.
To minimize steroid toxicity, a thrombopoietin receptor agonist (TPORA) should be the immediate second-line therapy for ITP patients who fail their initial course of corticosteroids. There is no need to trial multiple other therapies before considering a TPORA.
Concerns about bone marrow fibrosis with TPO receptor agonists have been resolved. The effect is a reversible increase in reticulin fibrosis, not the permanent collagen fibrosis seen in myelofibrosis. It resolves upon stopping the drug, so routine bone marrow biopsies for monitoring are unnecessary.
Pulsed dexamethasone provides no overall response rate benefit compared to a standard prednisone taper in first-line ITP treatment. It may offer a slightly faster response (by about one day) but carries a higher risk of acute steroid complications, particularly psychosis in older adults.
Some ITP patients with extremely low platelet counts don't bleed because their platelets are enormous. This is due to the principle of 'conservation of platelet mass.' Automated counters can undercount these large platelets, so the functional platelet count is higher than reported, reducing bleeding risk.
While not standard of care, TPO receptor agonists like romiplostim can be used in the third trimester of pregnancy to raise platelet counts above 75,000 for epidural anesthesia. This is considered a reasonable option after critical fetal development is complete, avoiding the need for pre-pregnancy splenectomy.
Historical data on high splenectomy success rates in ITP is outdated. For modern patients who have already failed multiple lines of therapy (e.g., corticosteroids and a TPORA), the likelihood of a curative response from splenectomy falls to around 40-45%, making it a less appealing option.