Smell in Covid-19 and Efficacy of Nasal Theophylline

Evidence of COVID-19 related anosmia and dysgeusia continues to accumulate daily. Currently, up to 80% of patients report subjective olfactory dysfunction (OD), and prevalence using objective olfactory testing could be even higher. We propose a phase II single-site, double-blinded, placebo-controlled randomized clinical trial to determine the efficacy and safety of intranasal theophylline, a known phosphodiesterase inhibitor in the treatment of asthma, as a possible treatment for COVID-19 related OD. Theophylline has shown benefit in similar clinical trials for post-viral OD.