Opioid painkillers, such as morphine, bring relief to those suffering the persistent pain that follows shingles.
Caused by the chicken pox virus, herpes zoster, shingles is not uncommon among older people. It produces a painful rash and the pain often persists once the rash has disappeared. This so-called post-herpetic neuralgia (PHN) can be hard to treat with conventional analgesics. Sometimes antidepressants are prescribed.

A team of Johns Hopkins Medical School has compared opioids - strong painkillers, like morphine - with antidepressants and placebo in a group of elderly patients with PHN. Thirty eight per cent of those on opioids reported pain relief, compared to 32 per cent of those on antidepressants and just 11 per cent of those on placebo.

In addition, 54 per cent of the patients preferred the opioid drug to the antidepressant (30 per cent). However, there were some side effects associated with opioids, such as constipation, nausea and dizziness.