What guidelines can be followed in devising a chronic analgesic regimen for treating cancer pain?
Guidelines frequently followed when treating cancer pain use a combination of different classes of analgesics to minimize the side-effects of any one medication. The com-bination should utilize drugs that work on the pain path-ways at different levels, so that the analgesics can have additive/synergistic effects.
A typical cancer pain regimen includes:
· Opioids with a set dose and extended-release mechanism (Table 76.1): act on opioid receptors in the brain and the spinal cord.
· NSAIDs: act by primarily inhibiting prostaglandin synthe-sis causing desensitization of peripheral pain receptors.
· TCAs: act by inhibiting the reuptake of serotonin and norepinephrine, which results in stimulation of the descending inhibitory pain tracts in the spinal cord.
· Anticonvulsants (optional): act on the neuropathic components of pain.
· Fast-onset, short-duration analgesics: given on a “prn” basis for episodic, breakthrough pain.