There is no clinical effect seen with oral naloxone, but, upon IV administration, opioid antagonism will occur, and the patient will experience withdrawal. The injectable form and the once weekly transdermal patch are indicated for the relief of moderate to severe pain. It is metabolized by the liver and excreted in bile and urine. Adverse effects include respiratory depression that cannot easily be reversed by naloxone and decreased (or, rarely, increased) blood pressure, nausea, and dizziness.