December 9, 2022

IV paracetamol clinically equivalent to hydromorphone for acute pain relief in older adults in the emergency department

IV paracetamol provides clinical pain relief not inferior to hydromorphone in older adults with acute pain seen in the emergency department

Use of intravenous (IV) paracetamol (acetaminophen) provides clinically equivalent pain relief to IV hydromorphone in elderly patients presenting to an emergency department (ED) with acute pain that would warrant the use of opioids, according to the results of a randomized trial by researchers from the Department of Emergency Medicine, Albert Einstein College of Medicine, New York, USA.

Older people frequently present to an emergency department with pain, which is often both under-recognized and under-treated. In fact, effective pain management in the elderly is a challenge since this group is at increased risk of adverse events associated with systemic analgesics. Additionally, some data suggests that older people are less likely to receive pain medication. In a study of 7,585 pain-related emergency department visits by patients aged 75 or older, these individuals were less likely than visits by patients aged 35 to 54 to result in the administration of an analgesic (49% versus 68.3%) or an opioid (34.8% versus 49.3%). IV hydromorphone is an opioid used in the management of acute pain, although its effectiveness is similar to IV morphine in the elderly. Additionally, IV paracetamol has been shown to be an effective analgesic in older people after major orthopedic surgery. However, it is uncertain whether IV paracetamol can provide a similar level of analgesia in older people presenting to an emergency department with acute pain, when an opioid would normally be considered.

For the current study, the US team undertook a randomized trial comparing IV paracetamol to IV hydromorphone in older adults with acute pain deemed sufficient to warrant the use of IV opioids. Participants were aged 65 and over and randomized to receive 1000 mg paracetamol IV or 0.5 mg hydromorphone intravenously. Pain was rated using a verbal scale from 0 to 10, with 0 being no pain and 10 being the worst pain imaginable and was rated at baseline and after 15, 30, 45, 60 , 90 and 180 minutes. Any adverse effects were assessed using open-ended questions. The primary endpoint was improvement in pain score from baseline after 60 minutes. For the secondary outcome, the researchers looked at the need to use additional medications for pain relief. The researchers also documented the proportion of patients achieving the minimum clinically important improvement in pain, defined as a 1.3 point change on the pain relief scale.

IV paracetamol and modification of pain relief

A total of 162 participants with a mean age of 74.5 years (53.5% female) were randomized equally between the two therapies. The median baseline pain score was 10 in both groups.

After 60 minutes, patients receiving paracetamol IV had a mean pain score improvement of 3.6 units, while those receiving hydromorphone IV had a mean improvement of 4.6 units (95% CI for the difference was 0.1 to 2). Additionally, a similar proportion (77% vs. 78%) of patients receiving paracetamol and hydromorphone, respectively, achieved the minimum clinically important improvement (1.3) after 60 minutes. However, a higher proportion of patients receiving paracetamol required additional analgesics compared to hydromorphone (46% versus 38%). Overall adverse effects were similar between the two groups. Finally, after 60 minutes, only 37% of those given paracetamol and 53% hydromorphone saw a >50% improvement in pain relief.

The authors concluded that although hydromorphone provided statistically superior pain relief to paracetamol, this difference was not clinically important, although they cautioned that these results may not generalize well outside of the population. studied.

Kolli S et al. A randomized study comparing intravenous hydromorphone to intravenous acetaminophen in older adult patients with severe acute pain Ann Emerg Med 2022