Short-Course Pentoxifylline Is Not Effective in Post-Traumatic Smell Loss: A Pilot Study

It has been suggested that systemic pentoxifylline may be beneficial in the treatment of olfactory dysfunction. The postulated mechanism of action involves nonselective competitive phosphodiesterase inhibition, leading to increased intracellular cyclic adenosine monophosphate and consequent increased olfactory neuron activity. This should in theory lead to improved olfactory function. We describe a pilot case series from our tertiary referral center of patients treated with oral pentoxifylline for olfactory dysfunction. Six patients with post-traumatic impairment who were treated with systemic pentoxifylline were included. Patients were treated with 200 mg of oral prolonged release pentoxifylline, 3 times a day for 21 days. Olfactory function was tested pre and post-treatment for odor threshold (T), discrimination (D), identification (I) and composite 'TDI' score using a psychophysical test battery, the "Sniffin' Sticks." Oral pentoxifylline was well tolerated and all patients completed the treatment period. There was a small improvement in odor threshold and identification scores, but these did not reach statistical or clinical significance. There were deteriorations in discrimination and composite TDI score, which did not reach significance. While our case series was small, systemic pentoxifylline did not appear to be beneficial in the treatment of hyposmia in this patient group.