<p><strong>Central Nervous System</strong>:&nbsp; Lightheadedness, dizziness, sedation, sweating, bizarre feelings, disorientation, hallucinations, psychosis. Some of these effects seem to be more prominent in ambulatory patients and those not experiencing severe pain, and may be relieved by reducing the dose slightly and lying down.<br />
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<strong>Gastrointestinal</strong>: Nausea and vomiting, constipation.</p>