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Acute Pain | Chronic Pain | General

Cost-effectiveness of analgesia in acute pain

Clinical bottom line

Adverse event rates rather than acquisition costs are the main cost driver, especially less common but more expensive events leading to hospital admission.


TH Rainer et al. Cost effectiveness analysis of intravenous ketorolac and morphine for treating pain after limb injury: double-blind randomised controlled trial. BMJ 2000 321.


There is an ongoing tension in healthcare where new interventions are concerned. New interventions tend to come at a higher price, but provide better outcomes or less harm. The question then is whether the benefits outweigh the costs, and how that might be quantified. Here we have a super example of how to settle the argument through a randomised trial.


Patients were those attending the accident and emergency department of a hospital in Hong Kong, where about 200,000 such emergency admissions occur every year. Those aged 16 years or over attending for a painful limb injury were randomised to receive either intravenous ketorolac or morphine. For each they received a loading bolus and then top ups until patients had good pain relief. Doses were chosen according to recommendations and results of a pilot study, and volumes of bolus and top up were identical.

The primary outcome was pain relief, and activity of professionals and healthcare costs.


There were 149 patients randomised. Their mean age was 54 years, and they were equally divided between the sexes. Most injuries were caused y falls or were crush injuries. Initial pain scores were 4/10 (moderate) at rest and 8/10 (severe) on movement.

Analgesia obtained was the same but many more patients given morphine (89%) had adverse events than with ketorolac (5%). Adverse events with morphine were typical for opioids, dizziness, drowsiness and nausea. Three patients given morphine were admitted to hospital because of the severity of the adverse events, compared with none given ketorolac.

Ketorolac had an acquisition cost three times greater than morphine, but when administration costs, adverse events, and especially admissions for adverse events were taken into account, ketorolac was much cheaper (Figure 1).

Figure 1: Costs for intravenous ketorolac or morphine according to criteria included


The choice of morphine over ketorolac might have saved €1 ($1) for each patients, but would have cost €20 ($20) more per patient in costs of administration and adverse events. This is a well designed and conducted study, and demonstrates that in making decisions we need to be broad in our thinking.