A sequestering subunit comprising an aversive agent and a blocking agent, wherein the blocking agent substantially prevents release of the aversive agent from the sequestering subunit in the gastrointestinal tract for a time period that is greater than 24 hours; a composition comprising a sequestering subunit in releasable form, wherein, optionally, the mechanical fragility of the sequestering subunit is the same as the mechanical fragility of the therapeutic agent in releasable form; a capsule or tablet comprising a sequestering subunit and a therapeutic agent; and a method of preventing abuse of a therapeutic agent.