[The potential P300 in the evaluation of the side effects of dexchlorpheniramine]

The antihistamine chlorpheniramine presents multiple adverse side effects on the central nervous system. In earlier work it has been observed that a dose equal to the one used in this study alters the evoked potentials PN (processing negativity) and MMN (mismatch negativity), which are, respectively, indicators of selective attention and of an automatic mechanism for detecting changes in auditory stimulation. AIMS. The aim of the present study was to evaluate the effects of a single 4 mg dose of dexchlorpheniramine on the evoked potential P300, to enable us to better define its effects on the central nervous system. Subjects and methods. Using the double blind procedure, half a sample consisting in 20 subjects was administered 4 mg of dexchlorpheniramine and the other 10 received placebo. 150 minutes after ingestion the potential P300 was recorded using an active oddball paradigm. Likewise, efficiency in detecting target stimuli was also evaluated.

results show that a single 4 mg dose of dexchlorpheniramine does not alter P300 nor efficiency in detecting target stimuli.

Results show that the dose used has no effect on voluntary processes involving the categorization of target stimuli nor on their detection. However, the alteration of other attentional mechanisms observed in previous work using the same doses suggests that it would be advisable to employ different evoked potential paradigms in the evaluation of the side effects other active principles or psychoactive substances have on auditory attention.