* history of olfactory dysfunction prior to covid-19 infection * use of concomitant therapies specifically for the treatment of olfactory dysfunction * history of olfactory dysfunction longer than 12 months * known existence of nasal polyps, prior sinonasal, or anterior skull-based surgery * dependence on theophylline for comorbid conditions such as asthma and copd * history of an allergic reaction to theophylline or other methylxanthines * history of neurodegenerative disease (ie. alzheimer's dementia, parkinson's disease, lewy body dementia, frontotemporal dementia) * pregnant or breastfeeding mothers * current use of medications with significant interactions with theophylline, which include cimetidine, ciprofloxacin, disulfiram, enoxacin, fluvoxamine, interferon-alpha, lithium, mexiletine, phenytoin, propafenone, propranolol, tacrine, thiabendazole, ticlopidine, and troleandomycin. * pre-existing arrhythmias or seizures

* history of olfactory dysfunction prior to covid-19 infection * use of concomitant therapies specifically for the treatment of olfactory dysfunction * history of olfactory dysfunction longer than 12 months * known existence of nasal polyps, prior sinonasal, or anterior skull-based surgery * dependence on theophylline for comorbid conditions such as asthma and copd * history of an allergic reaction to theophylline or other methylxanthines * history of neurodegenerative disease (ie. alzheimer's dementia, parkinson's disease, lewy body dementia, frontotemporal dementia) * pregnant or breastfeeding mothers * current use of medications with significant interactions with theophylline, which include cimetidine, ciprofloxacin, disulfiram, enoxacin, fluvoxamine, interferon-alpha, lithium, mexiletine, phenytoin, propafenone, propranolol, tacrine, thiabendazole, ticlopidine, and troleandomycin. * pre-existing arrhythmias or seizures

- history of olfactory dysfunction prior to covid-19 infection - use of concomitant therapies specifically for the treatment of olfactory dysfunction - history of olfactory dysfunction longer than 12 months - known existence of nasal polyps, prior sinonasal, or anterior skull-based surgery - dependence on theophylline for comorbid conditions such as asthma and copd - history of an allergic reaction to theophylline or other methylxanthines - history of neurodegenerative disease (ie. alzheimer's dementia, parkinson's disease, lewy body dementia, frontotemporal dementia) - pregnant or breastfeeding mothers - current use of medications with significant interactions with theophylline, which include cimetidine, ciprofloxacin, disulfiram, enoxacin, fluvoxamine, interferon-alpha, lithium, mexiletine, phenytoin, propafenone, propranolol, tacrine, thiabendazole, ticlopidine, and troleandomycin. - pre-existing arrhythmias or seizures

- history of olfactory dysfunction prior to covid-19 infection - use of concomitant therapies specifically for the treatment of olfactory dysfunction - history of olfactory dysfunction longer than 12 months - known existence of nasal polyps, prior sinonasal, or anterior skull-based surgery - dependence on theophylline for comorbid conditions such as asthma and copd - history of an allergic reaction to theophylline or other methylxanthines - history of neurodegenerative disease (ie. alzheimer's dementia, parkinson's disease, lewy body dementia, frontotemporal dementia) - pregnant or breastfeeding mothers - current use of medications with significant interactions with theophylline, which include cimetidine, ciprofloxacin, disulfiram, enoxacin, fluvoxamine, interferon-alpha, lithium, mexiletine, phenytoin, propafenone, propranolol, tacrine, thiabendazole, ticlopidine, and troleandomycin. - pre-existing arrhythmias or seizures