MO, USA 5/325 mg combination tablets are most frequently
used for managing breakthrough pain. Oxycodone
appears to act as a kappa, or other opioid-receptor, agonist with
a relatively low affinity for l-opioid receptors, in contrast to
morphine, which interacts primarily with l-opioid receptors.4
Some studies have shown that oxycodone is an effective medication
for non-malignant and malignant neuropathic pain.5 Paracetamol
(acetaminophen) is a component of many combination
analgesics.6 Its mechanism comprises some non-opioid mechanism,
yet to be elucidated, inhibition of spinal prostaglandin E2
release7 and bone destruction.8 Hepatic toxicity is the only serious
complication, but this is rare with doses less than 4 g/day.
Paracetamol has been officially included in the National Comprehensive
Cancer Network (NCCN) Cancer Pain Treatment
Guidelines for management of bone-cancer pain.9 The combination
of oxycodone and paracetamol can therefore alleviate not
only inflammatory but also neuropathic pain.10 A combination
analgesic is most effective when the individual agents act
through different mechanisms and act synergistically. By activating
multiple pain-inhibitory pathways, combination analgesics
can provide more effective pain relief for a broader
spectrum of pain, and might also reduce adverse drug reactions.
11–13