Disclosed in certain embodiments is an oral dosage form comprising a therapeutically effective amount of an opioid analgesic, an opioid antagonist and one or more pharmaceutically acceptable excipients; the dosage form further including a gelling agent in an effective amount to impart a viscosity unsuitable for administration selected from the group consisting of parenteral and nasal administration to a solubilized mixture formed when the dosage form is crushed and mixed with from about 0.5 to about 10 ml of an aqueous liquid.