Erlotinib hydrochloride tablets should be taken at about the same time each day. Each erlotinib dose should be taken with about 8 ounces of water, and should be taken 1 hour before or 2 hours after meals. The whole dose must be taken at one time. If you vomit after taking the tablet(s), you should only re-take the dose if the tablet(s) can still be seen and counted.