The present invention provides an oral dosage form comprising a first
composition and a second composition. The first composition comprises an
effective amount of a therapeutic agent and the second composition
comprises an effective amount of an adverse-effect agent. The
adverse-effect agent is covered with a coating that is substantially
insoluble in the gastrointestinal tract. In one embodiment, the
adverse-effect agent is coated with an outer base-soluble layer and an
inner acid-soluble layer. The therapeutic agent can be uncoated or can be
coated with a coating having an outer acid-soluble layer and an inner
base-soluble layer. The dosage form discourages administration of the
therapeutic agent by other than oral administration.