Carol,
When you have a bone marrow failure disease and are taking medicine or drugs, it's worth paying attention to all those cautions about side effects!
The list of drugs that can cause cytopenias goes on and on, from non-steroidal anti-inflammatory drugs (NSAIDs) to anti-epileptic drugs and all sorts of chemo-related drugs.
A 2009 article named
Drug-Induced Hematologic Syndromes lists many of the specific drugs that can produce cytopenias for myelodysplasia, aplastic anemia, sideroblastic anemia, pure red cell aplasia, immune thrombocytopenia, acute leukemia, and other related diseases.