A retrospective study by researchers at Rutgers University has found that opioid use, particularly in high doses, can cause “full or partial hearing loss”.
The study, published in The Journal of Medical Toxicology, reviewed records from the New Jersey Poison Control Center, based at Rutgers New Jersey Medical School, from 1999 to 2018 to determine the association between opioid use and degrees of hearing loss.
Over half of the affected cases had consumed heroin just prior to developing hearing abnormalities or tinnitus, followed by oxycodone, methadone and tramadol. 88 percent only reported a single substance exposure rather than polysubstance ingestion, implying the opioid itself directly harmed ear structures. However, complex neural biochemistry means many pathways likely contribute to observed ototoxicity.
Most people reported the condition affecting both ears, with 12 people experiencing deafness, 15 partial or total loss of hearing acuity, 10 tinnitus and four a mix of symptoms.
Opioid Use and Hearing Loss
While some people may regain their hearing, the loss could be permanent with others — 21 percent of those reporting the condition had no improvement in hearing when they were discharged from the hospital.
“The delicate structures of the inner ear are very susceptible to injury if oxygen supply is insufficient, as well as to the direct effect of toxins like opioids,” said co-author Lewis Nelson, chair of the Department of Emergency Medicine.
“Although the study found a link with heroin, toxicity to the ear can occur with every opioid. This study supports what has been found in animal studies, which is that any opioid can cause hearing loss. This might be because we already have built-in opioid receptors, or binding sites, in the inner ear. Activating them may trigger this injury in some patients.”
–Diane Calello, Executive Director of NJ Poison Control Center
Animal research also demonstrates that commonly abused substances like legal prescription narcotics and illicit heroin stress hearing pathways. Overactivating certain receptors causes free radicals and oxidative stress while reducing oxygen-rich blood delivery to inner ear structures. However, human clinical data remains relatively limited thus far.
The researchers said health care providers should be aware of the association with opioid use when evaluating a patient with hearing loss.
