<unk>  or<unk>  switching is the process of changing one<unk>  to another to improve pain control or reduce unwanted side effects. This technique was introduced in the 1990s to help manage severe chronic pain and improve the<unk>  response in cancer patients. In order to obtain adequate levels of pain relief, patients requiring chronic<unk>  therapy may require an increase in the original prescribed dose for a number of reasons, including increased pain or a worsening disease state. Over the course of long term treatment, an increase in dosage cannot be continued indefinitely as unwanted side effects of treatment often become intolerable once a certain dose is reached, even though the pain may still not be properly managed. One strategy used to address this is to switch the patient between different<unk>  drugs over time, usually every few months.<unk>  requires strict monitoring in patients with ongoing levels of high<unk>  doses for extended periods of time, since long term<unk>  use can lead to a patient developing tolerance to the analgesic effects of the drug. Patients may also not respond to the first<unk>  prescribed to them at all, therefore needing to try another<unk>  to help manage their pain. A patient's specific response and sensitivity to<unk> s include many factors that include physiology, genetics and pharmacodynamic parameters, which together determine the amount of pain control and tolerance of a particular<unk> .
Opioid rotation
Lateral release 
Counterstimulation
Paraspinal inhibition
Co-stimulation
Neurostimulation
Burst suppression
Neural facilitation