Also, he said, "some people who lose their sense of smell get better anyway, especially if they have mild cases, so they would have gotten better with or without treatment."
But, Kuppersmith added, for certain patients this might be a helpful option if other things don't work.
Side effects of theophylline were minimal, the researchers noted, but can include jitteriness, nervousness and difficulty falling asleep.
Henkin said that the findings need to be verified with a clinical trial. His team is now looking at ways to deliver the drug intranasally (this study involved pills). He also needs a drug company to develop and market the medication, should it continue to prove useful.
The Sense of Smell Institute has more on hyposmia.
SOURCES: Robert I. Henkin, M.D., Ph.D., director, Center for Molecular Nutrition and Sensory Disorders, Washington, D.C.; Ronald Kuppersmith, M.D., clinical assistant professor, surgery, Texas A&M Health Science Center College of Medicine, otolaryngologist, Texas ENT and Allergy, College Station, and president-elect, American Academy of Otolaryngology-Head and Neck Surgery; June 2009, American Journal of the Medical Sciences