Cutaneous complications of pentazocine injections

Extensive cutaneous fibrosis and ulceration caused by methadone injection

“…These changes occurred between 2 weeks and 3 years after injection of pentazocine. Similar vascular changes were reported previously by Parks et al 3 . and it has been proposed that these vascular changes are central to the mechanism of fibrosis.…”

Pentazocine‐induced ulcers revisited

“…postulated that the pain of the needle puncture and the resistance of fibrotic panniculus often lead to the superficial deposition of pentazocine. They demonstrated in animal experiments that superficial ID injections lead to ulcerations, whereas SC and IM injections lead to sclerosis . Similar observations have been made by other authors, who have concluded that ulcerations result from the superficial deposition of the drug in indurated skin that is difficult to inject .…”

“…They demonstrated in animal experiments that superficial ID injections lead to ulcerations, whereas SC and IM injections lead to sclerosis . Similar observations have been made by other authors, who have concluded that ulcerations result from the superficial deposition of the drug in indurated skin that is difficult to inject . However, others are of the opinion that SC injections produce cutaneous lesions, whereas IM inoculations are responsible for causing myopathy .…”

“…It was suggested that the deposition of crystals from IM injections of pentazocine resulted in late fibrosis and calcification, leading to an inflammatory response over a long period in this patient . All of these observations cannot be explained by any single mechanism of those hypothesized above, which also fail to explain the occurrence of cutaneous lesions in areas far from the injection site . The present patient exhibited ulcers at the sites of both IV and IM injections, but although fibrous myopathy of the right ring and little fingers was observed, no widespread induration or sclerosis were noted.…”

Atypical ulcerations

“…Previous cases show that cutaneous changes develop between 2 weeks to 3 years after commencement of pentazocine injection 1–6 . Our patient is unusual in that she received pentazocine injection for 20 years but ulcers only developed 9 years after the injections were stopped.…”