Morphine potentiates salmonella infection

Excerpt

This animal study showed that implantation of subcutaneous morphine dramatically reduced survival and increased bacterial burden. This effect appears to be mediated via opiate receptors. Although the dose appears large, the steady state plasma levels obtained are within the analgesic range for the drug (0.6 μg per ml). The timing of the morphine dose seems to be important, with worsened outcome if bacteria and morphine are given simultaneously. Naltrexone extended the mean survival time (MST), and blocked colonisation of salmonellae yet did not reduce mortality. The authors hypothesise that this may be due to the fact that naltrexone is a competitive antagonist and endogenous opiates would reduce its effectiveness. The increase in mortality may be due to slowing of the gastrointestinal transist time, or increased gut permeability (for which there is some experimental evidence). This study, albeit in an animal model, supports other animal data that morphineis immunosuppressive and hence has important implications for ICU patients, post operative patients and IV drug abusers. …