The invention relates to the compounds of formula I and formula II or its pharmaceutical acceptable salts, as well as polymorphs, solvates, enantiomers, stereoisomers and hydrates thereof. The pharmaceutical compositions comprising an effective amount of compounds of formula I or formula II, and methods for treating chronic pain in a disease may be formulated for oral, buccal, rectal, topical, transdermal, transmucosal, intravenous, parenteral administration, syrup, or injection. Such compositions may be used to treatment of acute pain (such as post-operative pain), palliative care to alleviate the severe, chronic, disabling pain of terminal conditions such as cancer, and degenerative conditions such as rheumatoid arthritis, non-malignant chronic pain, chemotherapy induced pain, musculoskeletal pain, sciatica, radiculopathy pain, migraine, neuropathic pain, post herpetic neuralgia, neuralgia pain, multiple sclerosis, multiple sclerosis, restless legs syndrome (RLS), cluster headache, depression, fibromyalgia and amyotrophic lateral sclerosis (ALS).
