Morphine Unsafe for Some Children After Tonsillectomy

Lara C. Pullen, PhD

January 27, 2015

After tonsillectomy, ibuprofen in combination with acetaminophen provides safe, effective analgesia for children. In contrast, morphine can cause life-threatening oxygen desaturation in certain children, and therefore its use should be avoided when possible.

Lauren E. Kelly, PhD, from Western University, London, Ontario, Canada, and colleagues published the results of their prospective clinical trial online January 26 in Pediatrics. Their study randomly assigned children between the ages of 1 and 10 years (n = 91) into two treatment groups receiving either acetaminophen (10 - 15 mg/kg) plus oral morphine (0.2 - 0.5 mg/kg) or acetaminophen plus oral ibuprofen (10 mg/kg). The children received their postoperative pain killers at home after an outpatient tonsillectomy to treat sleep disordered breathing, which ranged in severity from snoring to obstructive sleep apnea.

Codeine was previously contraindicated for children after tonsillectomy for obstructive sleep apnea after reports of respiratory depression and death. "Although the Boxed Warning suggests avoiding codeine for post-tonsillectomy pain management, no recommendations have been made as to safe and effective alternate analgesic in pediatric patients," the authors write. "Owing to a fear of increased bleeding, many surgeons have been hesitant to prescribe nonsteroidal anti-inflammatory drugs." For these reasons, oral morphine is now used for pain control after tonsillectomy in children.

The investigators measured oxygen desaturation with a finger oximeter. On the first night after surgery, 68% of children in the ibuprofen group showed improvement in oxygen desaturation incidents, whereas only 14% of children in the morphine group showed similar improvement.

The study found that morphine used after tonsillectomy increased the risk for oxygen desaturation relative to ibuprofen (average increase, 11.17 ± 15.02; P < .01). Moreover, one child in the morphine group experienced a life-threatening adverse drug reaction that included oxygen desaturation.

Tonsillar bleeding events or analgesic effectiveness did not differ between the two groups.

"These results should prompt clinicians to re-evaluate their post-tonsillectomy pain treatment regimen. Due to the unpredictable respiratory side-effects of morphine, its use as a first-line treatment with current dosage ranges should be discontinued for outpatient tonsillectomy," said study coauthor Doron Sommer, MD, from McMaster's Michael G. DeGroote School of Medicine, Hamilton, Ontario, in a university news release.

Tonsillectomies are one of the most common pediatric surgical procedures. Certain patients have been identified as having poor post-tonsillectomy outcomes. These include those with smaller tonsils, narrow epipharyngeal airspace, and maxillary/mandibular protrusions.

Children who have received a tonsillectomy may be more at risk from the adverse respiratory effects of morphine as a result of respiratory comorbidities such as unresolved apnea, craniofacial disorders, and bronchopneumonia.

The current results follow previous studies by the same group that found no statistical difference in reported pain and satisfactory pain in patients given codeine post-tonsillectomy and patients given ibuprofen. Moreover, the investigators found that some children are genetically ultrarapid metabolizers of codeine, placing them at increased risk for respiratory failure and death. The US Food and Drug Administration has issued warnings about the use of codeine in pediatric tonsillectomy patients.

The authors have disclosed no relevant financial relationships.

Pediatrics. Published online January 26, 2015. Abstract


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