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Original Article
May 2001

Effects of Difluoromethylornithine Chemoprevention on Audiometry Thresholds and Otoacoustic Emissions

Author Affiliations

From the Department of Otolaryngology (Drs Doyle, Shanks and Ms Galus) and the Department of Medicine and the Chao Family Comprehensive Cancer Center (Drs McLaren and Meyskens), University of California, Irvine, and the Department of Audiology, Veterans Affairs Medical Center, Long Beach, Calif (Dr Shanks).

Arch Otolaryngol Head Neck Surg. 2001;127(5):553-558. doi:10.1001/archotol.127.5.553

Objectives  To determine the effects of long-term, low-dose difluoromethylornithine (DFMO) on audiometric thresholds and distortion product otoacoustic emission (DPOAE) levels in humans.

Design  A prospective, randomized, placebo-controlled phase 2 clinical trial of DFMO in participants with a prior adenomatous colonic polyp.

Setting  Academic tertiary care referral center.

Participants  One hundred twenty-three volunteer subjects with colorectal polyps and normal hearing for the frequencies 250 through 2000 Hz.

Interventions  Subjects were randomized to receive placebo or oral DFMO at daily dosages between 0.075 and 0.4 g/m2 of body surface area for 12 months.

Outcome Measures  Pure-tone audiometric thresholds for the frequencies 250, 500, 1000, 2000, 3000, 4000, 6000, and 8000 Hz and DPOAE levels were measured at baseline and 1, 3, 6, 9, and 12 months after starting treatment with DFMO or placebo and 3 months after cessation of treatment if there was a suggestion of possible changes at the 12-month measurement.

Results  At these low dosages, there was little evidence for shifts in auditory pure-tone thresholds, and there were no statistically significant shifts in DPOAE levels. For auditory pure-tone thresholds, there was a subtle, approximately 2- to 3-dB hearing level decrease in hearing sensitivity for the 2 higher DFMO dosages, but only at the 2 lowest frequencies, 250 and 500 Hz.

Conclusions  Administration of low-dose DFMO for 12 months did not produce hearing loss, in contrast to prior studies that used higher dosages.