What is the WHO ladder?
The World Health Organization (WHO) has devised a protocol for treating pain utilizing a tiered approach. This protocol allows for the use of less potent medications initially (first tier), increasingly more potent medications (next tiers) being added in a stepwise approach until the patient is comfortable. The WHO states that about 85% of cancer patients can be kept comfortable using this protocol.
First-tier medications include non-opioid analgesics such as nonsteroidal anti-inflammatory drugs (NSAIDs), tricyclic antidepressants (TCAs), and anticonvulsants. Second-tier medications include “weak opioids,” which have ceiling dosages due to their combination with acetaminophen or NSAIDs. Third-tier analgesics in the WHO ladder include all sole opioid preparations, both short-acting and extended release. Despite the addition of large doses of opioids in the third tier, the non-opioid medications from tier 1 should be continued. A good knowledge of opioid equipotency conversions is necessary to be able to change from one opioid to another.
The WHO ladder can be further extrapolated clinically to include invasive techniques. Thus, oral analgesics are tried first, followed by intravenous opioids, analgesia via tunneled epidural catheters, implantable analgesic devices, and finally neuroablative procedures.