Opioid-induced myoclonus and hyperalgesia following a short course of low-dose oral morphine.

A 76-year-old man was admitted to hospital with a right-sided fractured neck of femur requiring repair via a cemented hemiarthroplasty. Intraoperatively he received 10 mg of intravenous morphine. Post-operatively he received a short course of low-dose oral opioids and subsequently developed myoclonic jerks and hyperalgesia. The opioids were discontinued and both adverse effects resolved. This case report discusses the concurrent development of myoclonus and hyperalgesia following a low dose of opioids and explores possible management options.