Problems with opiates in cancer pain: parenteral opioids

Morphine is the preferred drug for the management of moderate-severe chronic cancer pain. The best route of administration is by mouth because it is simple, safe, convenient, inexpensive and effective. Non-oral modes of administration should be only considered if (a) the oral route be comes unavailable or (b) there is documentation of failure of maximal doses of oral morphine and coanalgesic drugs. Recent developments have made new routes of morphine administration fashionable - in the absence of supportive pharmacokinetic or pharmacodynamic data - even when departure from established practice is not justified. It is important for clinicians to be familiar with the practicalities and problems that limit the utility of the non-oral routes, and the state of current understanding of these options will be reviewed.