Chronic pain is defined as pain that persists beyond normal tissue healing time, which is assumed for 3 months by the IASP. The symptoms include either continuous or intermittent pain, that could be caused by tumor or other multiple etiologies. The consequence of uncontrolled chronic pain presents not only physiologic symptoms but also psychiatric disorders leading to severely impact daily living.~In Thailand, the use of methadone for pain management has been limited because physicians are not familiar with its dosing and concern about the risk of drug accumulation and cardiac arrhythmia. Therefore, the aim of this study is to evaluate the efficacy and safety of a protocol of methadone dosing in outpatients with severe chronic pain.~Thirty four chronic pain patients will be included to initiate methadone use following the protocol. Pain scores, pain interferences scores, neuropathic pain score, severity of adverse effects, and QTc intervals will be assessed at baseline, and two, four, eight, and twelve weeks after starting methadone.~The approved protocol of methadone therapy obtained from this study could be clinically utilized by physicians for severe chronic pain management.
Methadone is a synthetic mu opioid agonist that has been proved as clinically effective in pain management. However, methadone usage for pain control in Thailand has been limited because physicians are not familiar with its dosing and concern about the risk of drug accumulation and cardiac arrhythmia. Therefore, this prospective study was conducted to evaluate the efficacy and safety of a methadone protocol in Thai patients with severe chronic noncancer and cancer pain.