The largest study ever conducted on opioid analgesics found that these commonly prescribed drugs often provide only limited short-term relief for acute pain, and in some cases, no meaningful effect at all.
Researchers at the University of Sydney led the study, which looked at the effectiveness and safety of opioid drugs such as codeine, morphine, oxycodone and tramadol. This analysis combined evidence from 59 systematic reviews covering over 50 acute pain conditions affecting both children and adults.
Published in a magazine drugthis review provides the most comprehensive assessment to date of where opioids are helpful, where they are not helpful, and where evidence remains limited.
“Opioids are one of the most commonly prescribed treatments for acute pain, but our review found that opioids do not produce greater or longer-lasting analgesic effects than placebo for most acute pain conditions, and the analgesic effects usually last only a few hours,” said lead author Associate Professor Christina Abdel-Shaheed from the School of Public Health at the University of Sydney.
“Overall, oral opioids were only slightly better than placebo for acute musculoskeletal pain, which is often prescribed 6 to 48 hours after starting treatment. Opioids also had an increased risk of side effects when used for acute musculoskeletal pain, some types of postoperative pain, or traumatic extremity pain.
“By showing that their effects are generally small, short-lived, absent for many common conditions, and even harmful, our study challenges the widely held belief that opioids are the most effective ‘go-to’ option for acute pain.” ”
Where opioids work and where they don’t work
Researchers have found that opioids provide modest short-term analgesic effects for certain acute conditions. These include abdominal pain, pain after dental surgery, ear procedures, extremity trauma, childbirth, Caesarean section, bunionectomy (bunion removal), and more.
However, for some other symptoms, the drug had no advantage over placebo. These include pain experienced by some types of extremity surgery, pain from kidney stones, pain after tonsillectomy, and pain experienced by newborns using breathing support devices.
The review also found that effects on topical opioid treatments (patches) used for heart-related pain, pain after hysterectomy (removal of a woman’s uterus), and dermatological (skin) pain were inconsistent over time.
Side effects and safety concerns
In addition to limited efficacy, opioids are associated with a high risk of side effects in several situations, including acute musculoskeletal pain, traumatic extremity injuries, and pain after some surgeries. Common side effects include nausea and vomiting.
The researchers noted that very short-term opioid use can reduce pain for certain acute conditions, but regular use carries significant risks. These include tolerance, dependence, misuse, overdose, hospitalization, and death.
The study also highlighted concerns about the quality of available safety data. According to the authors, many clinical trials do not adequately report side effects, suggesting that the true risks associated with opioid use may be greater than currently reported.
Overall, there is no evidence to support the routine use of opioids for acute pain. The researchers also noted that some studies evaluated only a single dose, which may not accurately reflect how these drugs are used in daily medical practice.
Risk of dependence can increase rapidly
“Sustained use of opioid drugs can develop quickly (sometimes within days) after initial use and can occur with regular use for acute pain,” said co-author Dr Stephanie Matheson, from the Institute of Musculoskeletal Health and School of Pharmacy at the University of Sydney.
“When prescribing opioids, it is important to educate patients about the potential harms of opioids and to ensure that physicians prescribe these drugs judiciously (in the lowest effective doses and for the shortest amount of time) for acute pain,” she said.
Co-lead author Joshua Zadro, associate professor at the university’s Institute of Musculoskeletal Health and School of Health Sciences, said the findings had wide-ranging implications.
“These findings are important for patients of all ages who experience acute pain, physicians who treat these conditions, and policy makers who regulate the safe use of these medicines in their communities.”
