PCP users may experience sometimes report an "out-of-body" experience where they feel detached from reality, or one's consciousness is disconnected from reality.
Moderate to high doses of GHB are known to cause nausea to the point of having to vomit.
Doctors argue whether the withdrawal syndrome leaves individuals who take sleeping medication worse than they would be without the drug, but evidence suggests that it often does.
The most common side effects that individuals experience when using Opana include, but are not limited to: constipation, nausea, vomiting and stomach pain, blurred vision, anxiety, abdominal pain, diarrhea, loss of appetite, dizziness, headache, anxiety, memory problems, and insomnia.