The structurally unrelated antihistamine triprolidine does not induce cell death. (A) The chemical structures of cyproheptadine and triprolidine are shown. (B) LP-1 and KMS11 myeloma and OCI-AML2 and Jurkat leukemia cells were treated with increasing concentrations of cyproheptadine (CYP) and triprolidine (TPL). Seventy-two hours after incubation, cell viability was measured by MTS staining. Data represent the mean percentage plus or minus SD of cell viability relative to untreated controls.