WHO Analgesic Ladder
This article discusses the WHO analgesic ladder at an advanced level and describes its relevance to acute pain management.
- To understand the basis of the WHO analgesic ladder and its clinical application
- To recognise the limitations of the ladder and and have an understanding of alternative approaches to managing acute pain
- To understand the concept of multimodal analgesia and its importance in managing pain effectively and safely
WHO Analgesic Ladder
An analgesic is a member of the group of drugs which are used to relieve pain, also known as “painkillers”. The word analgesic derives from Greek an ("without") and algos ("pain").
The analgesic ladder was designed by the World Health Organisation (WHO) as a conceptual framework to assist in the prescription of analgesic drugs . The ladder was initially introduced to improve the pain control of patients with cancer pain, however, it has lessons for the management of acute pain as it employs a logical strategy to manage pain. Hence today, it forms the basis of managing pain in the clinical environment.
The ladder advocates a stepped approach to the use of painkillers from these analgesic groups:
- Non-opioid analgesics i.e. paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs)
- Weak opioids i.e. tramadol, codeine
- Strong opioids i.e. morphine, fentanyl
- Adjuvants - adjuvant analgesics are drugs which were not originally for pain but rather for other conditions. They are a diverse group of drugs that includes antidepressants, anticonvulsants and others
At every step of the analgesic ladder non-opioid analgesics form the basis of the pain management. Paracetamol and NSAID (if not contraindicated) should always therefore be prescribed with opioid analgesia (weak or strong). This is known as multi-modal analgesia and is the concept that pain is best managed, not by a single drug or therapy, but by the combination of several analgesics to achieve more effective relief than analgesics administered individually. Evidence has demonstrated that when this happens pain relief is better, smaller amounts of pain killers are needed and less side effects occur. Most drugs induce analgesia through a single mechanism of action  however, clinical pain originates from multiple sources and often has different aetiologies. It has been proposed that through utilising this multi-modal approach of combining two or more analgesics with differing mechanisms of action, the efficacy of the overall analgesia can be dramatically increased .
A rigorous systematic review by McQuay & Moore  demonstrated that the combination of paracetamol and a NSAID with an opioid improves the efficacy of the treatment and also reduces adverse events associated with those individual treatments. The combination of paracetamol and NSAIDS with opioids has been shown to reduce the amount of opioids required to achieve the same effect by 20-30% . This ideology is the basis of the WHO Analgesic Ladder and has subsequently informed best practice guidelines nationally.
Figure 1: WHO Analgesic Ladder
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