Topiramate analogs have substituents at the sulfamate group, 9-position, or 10-position. Topiramate analogs may include immunogenic moieties to prepare anti-topiramate antibodies, or antigenic moieties for immunodiagnostic assays. Also, the topiramate analog can include tracer moieties for detecting the presence or amount of the analog during an immunodiagnostic assay. Additionally, the topiramate analogs can be used in immunodiagnostic assays to compete with topiramate for binding with anti-topiramate antibodies. Such an immunodiagnostic assay can be used for detecting the presence of topiramate in a sample obtained from a subject previously administered topiramate by the following: combining an anti-topiramate antibody and a topiramate analog with a sample to form a first composition; allowing any free topiramate from the sample and the topiramate analog to compete for binding with the antibody; detecting binding between the topiramate analog and the antibody.