January 2019

Improvement of Smell Function after Intranasal Theophylline

After intranasal theophylline 66% of patients reported improved smell function.

We evaluated smell function in 94 patients with loss of smell acuity. Each patient was treated with an intranasal theophylline spray, 40µg in each nostril once daily for a period of two to twelve months. Each patient tolerated the spray without any side effects.

After two to four months of treatment 62 of the 94 patients reported improvement of smell acuity. Each patient began at 0 and rated improvement on a scale from 0-100%. Improvement of 12±2% (mean±SEM) occurred after two to four months of treatment, 15±3% improvement after five to eight months of treatment and 21±4% improvement after nine to twelve months of treatment.

After onset of smell improvement and continuation of the nasal spray on a once daily basis improvement also occurred in taste and flavor perception. Improvement was dependent on continued daily use of theophylline and continued as long as the nasal spray was used.

First, patients noted an improvement in odor detection. Overtime, patients noted an improvement not only in the detection of odors but also in the character of each odor such that the full nature of each odor was begun to be appreciated. Thus, while patients initially noted that they could begin to detect odors that they could not prior to treatment over time they gradually noted the full character of each odor, began to be recognized.

The full character of the odor occurred more slowly than the detection of odors. The full character of odors gradually increased until the entire panoply of an odor character was fully appreciated. Thus, the character of a coffee odor gradually increased in both intensity and clarity with the coffee odor becoming fuller and more robust similar to the character appreciated prior to the loss of smell. Overtime it became more like coffee used to smell.