Hi, thanks for asking in Healthcare Magic. Severe pain can result in psychological and physiological consequences. Arthritic pain is usually longstanding, more in the morning as soon as getting up. The reason for your severe abdominal pain and weight loss should first be established. Hydrocodon is an opioid analgesic and though it is very effective initially the analgesic action wanes off after some time. Being an opioid analgesic, Hydrocodone can result in side effects like addiction, respiratory depression and severe constipation (which again can aggravate your pain) Fentanyl patches are preferred if Hydrocodone does not help. Gabapentin is more effective mainly in Diabetic neuropathy and neuralgia due to herpes and not in arthritic or nonspecific pain. Drugs used in the treatment of depression like Amytryptilline, Fluoxetine, Sertraline can be used in the treatment of chronic pain like arthritis, fibromyalgia, neuropathic pain, low back pain and pelvic pain. But they result in moderate pain relief and takes several weeks for complete action. Although that result in many side effects, they don t cause addiction and respiratory depression. They will relieve your depression, They also increase appetite and cause weight gain. I hope this is useful to you.