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Published on: July 29, 2014
Morphine-induced hearing loss
Leire Leache1, Irene Aquerreta2, Libe Moraza1
1Pharmacy Services, Clínica Universidad de Navarra, Pamplona, Spain.
Purpose:
A case of severe bilateral sensorineural hearing loss associated with oral morphine is reported.
Summary:
A 52-year-old Spanish man was admitted to the intensive care unit with a Glasgow Coma Scale score of 3, a fever, and sudden hearing loss with tinnitus in both ears. His medical history included type 2 diabetes mellitus, depression, sleep disorder, and hypertension. The patient also had pyelonephritis in 2011 and pulmonary embolism in 2014, requiring the placement of an inferior vena cava filter and chronic anticoagulation. His hearing loss appeared after the initiation of oral morphine, specifically on the eighth day of treatment, with increasing dosages of up to 120 mg daily. We did not find any other possible causes of the hearing loss. Ototoxicity is an adverse reaction of ibuprofen and acetaminophen, but the patient received only three doses of ibuprofen 600 mg and did not require acetaminophen. The patient's other medications did not have ototoxicity as an adverse reaction, and the patient confirmed not to have received any salicylate product. Brain magnetic resonance imaging discarded other possible causes of hearing loss. Our patient's hearing loss did not resolve after opioid discontinuation, and the use of hearing aids was necessary. According to the Naranjo et al. adverse drug reaction probability scale, this event would be classified as "probable."
Conclusion:
A 52-year-old man developed tinnitus and hearing loss after receiving high doses of oral morphine sulfate. His hearing loss did not fully resolve after the discontinuation of morphine, and he required the use of hearing aids.
Insights
Oral morphine may cause severe hearing loss and tinnitus. This case report details a patient who developed these symptoms after high-dose oral morphine, requiring hearing aids even after discontinuation.
Area of Science:
- Otolaryngology
- Pharmacology
- Clinical Toxicology
Background:
- Opioid analgesics, such as oral morphine, are widely prescribed for pain management.
- Sensorineural hearing loss and tinnitus are potential, though rarely reported, adverse effects of certain medications.
Observation:
- A 52-year-old male patient experienced sudden bilateral sensorineural hearing loss and tinnitus.
- These auditory symptoms emerged after the initiation of high-dose oral morphine (up to 120 mg daily).
- Extensive investigations ruled out other common causes of hearing loss, including other medications and neurological conditions.
Findings:
- The patient's hearing loss was temporally associated with oral morphine use.
- The adverse drug reaction probability scale classified the event as 'probable' morphine-induced ototoxicity.
- Hearing loss persisted and required hearing aid use even after the discontinuation of oral morphine.
Implications:
- This case highlights the potential ototoxicity of oral morphine, emphasizing the need for vigilance in patients experiencing auditory changes during opioid therapy.
- Further research is warranted to elucidate the mechanisms of opioid-induced ototoxicity and establish clear diagnostic criteria.
- Clinicians should consider morphine-induced ototoxicity in the differential diagnosis of sudden hearing loss and tinnitus, particularly in patients on high-dose or long-term opioid treatment.
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