Smell in Covid-19 and Efficacy of Nasal Theophylline

Post-viral olfactory dysfunction has numerous known adverse effects such as loss of cortical gray matter and decrease in quality of life. COVID-19 related olfactory dysfunction has already been shown to be correlated with depression and decreased quality of life, so finding an effective treatment is imperative. Intranasal and oral corticosteroids as well as olfactory training are currently used to treat post-viral OD; however they have demonstrated limited efficacy and there is no current gold standard of care. There is no current consensus on the pathogenesis of COVID-related anosmia; however evidence for post-viral olfactory dysfunction suggests sensory axonal regeneration and olfactory signaling may rely on elevated levels of secondary messengers cAMP and cGMP, a known effect of theophylline. In this phase II treatment trial, patients will be allocated 1:1 to receive either intranasal theophylline irrigation or placebo for six weeks. Various smell surveys and scratch-and-sniff tests will be utilized to capture changes in smell ability. Due to COVID-19, this study will be conducted virtually, except for the first ten enrolled patients who will undergo one serum theophylline test. This study is limited to patients living in Missouri or Illinois.