CDP-choline: repeated oral dose tolerance studies in adult healthy volunteers.

Cytidine diphosphate choline (CDP-choline, citicoline, Somazina) was administered to 12 adult healthy volunteer subjects in two short-term chronic oral dose regimens (600 mg X day-1 and 1g X day-1), each of 5 consecutive days, and compared with a corresponding regimen of matched placebo. Transient headaches were the only untoward events recorded, occurring in 4 and 5 subjects, respectively, on the lower and higher dose regimens but in only one subject during placebo administration.