Effect of overuse of the antimigraine combination of indomethacin, prochlorperazine and caffeine (IPC) on the disposition of its components in chronic headache patients.

Overuse of IPC combination in chronic headache patients is associated with increased plasma levels of indomethacin and caffeine, and with delayed elimination of indomethacin; the high and sustained concentrations of these drugs may cause rebound headache, organ damages, and perpetuate medication-overuse headache.