Background: Apart from olfactory loss due to sinu-nasal disease therapy of olfactory dysfunction is a difficult task.
Methods: Own investigations were carried out using alpha-lipoic acid (Hummel et al. 2002) and caroverine (Quint et al. 2002) in both patients with posttraumatic olfactory dysfunction and patients with olfactory loss following viral infections. Both studies were designed as unblinded trials; the study using caroverine contained an arm where patients received zinc.
Results: While data from these investigations are preliminary both studies indicated a beneficial effect of the medication on olfactory loss. Therapeutic principles may involve the release of nerve growth factors through alpha-lipoic acid and the NMDA-antagonistic action of caroverine which might act at higher order centers of olfactory processing.
Conclusions: These studies and other work indicate that olfactory loss may be treated through different pharmacological approaches. However, only double-blind, randomized, controlled trials will tell whether these effects are due to the potential pharmacological activity of these drugs, or, whether they merely reflect spontaneous recovery as it is seen in a relatively large percentage of patients suffering from olfactory dysfunction.