Calcific myofibrosis due to pentazocine abuse: a case report.

Introduction: Pentazocine, a synthetic narcotic analgesic, is commonly used for the relief of moderate to severe pain secondary to various conditions. It is usually well tolerated; however, adverse effects are not uncommon, especially when higher doses are used and when it is used in a dependent fashion. There have been reports of various complications associated with its use, including skin fibrosis, skin ulceration, abnormal skin pigmentation and symmetrical myopathy with fibrous myopathy.