Calcific myofibrosis due to pentazocine abuse: a case report

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. Fibrosis has usually been reported in the muscles at the site of injection of the drug. Being opioid in nature, it has a high abuse potential.

Here we report a case of pentazocine-induced calcific myofibrosis in a 42-year-old man involving muscles which were not injected with pentazocine.

This case highlights the care that needs to be taken when prescribing opioid analgesics, such as pentazocine, as routine painkillers. Patients who have history of substance abuse are more likely to abuse other agents, including prescription drugs. Rare consequences such as calcific myofibrosis are devastating and can cause significant lifelong disability.