Some chemicals in inhalants may produce various pharmacological effects similar to that of prescription drugs.
Opiates affect the limbic system, which controls emotions which can produce feelings of pleasure, relaxation, and contentment.
The effects of fentanyl are felt almost immediately and it is very effective in treating even the worst cases of pain, sometimes referred to as breakthrough pain.
Opana is sometimes used prior to surgery to cause sedation and to reduce anxiety.