@burcidi-- I know that clonidine is effective for nerve pain. Perhaps it's not effective for other types of pain. I used a clonidine patch for nerve pain and it was definitely helpful.
Clonidine is also used for pain symptoms caused by withdrawal from certain medications and drugs. Most people don't know that withdrawal from certain drugs, like strong opiates such as heroin, can cause physical pain. Clonidine not only helps with pain, but it also helps relieve anxiety, sleep problems and hot flashes during withdrawal.