Oral dosage forms containing an opioid antagonist in a sequestered form are described. The opioid antagonist is sequestered such that it is not released or substantially not released in the gastrointestinal tract from the dosage form which is administered orally intact. However, when the dosage form is chewed, crushed, heated or dissolved in a solvent, and then administered orally, intranasally, parenterally or sublingually, the opioid antagonist is released and at least partially blocks effects of the opioid agonist.