Can you take zyrtec (cetirizine) 10 mg 2 times a day for a severe bee sting?

No...: The maximum dose of zyrtec is 10 mg. If the reaction is severe, meaning severe swelling, severe pain, shortness of breath, wheezing my recommendation is to get immediate attention at the closest ed. If not that severe could wait until next day when the next dose is due. Benadryl (diphenhydramine) is also alternative treatment.

Not recommended: Dosage of zyrtec (cetirizine) is 10 mg daily. This dosage has not changed since it went from prescription only to over the counter. Sometimes doctors allow a larger dose "off label" if the weight of a patient is much heavier than the average adult or has been demonstrated to be a rapid metabolizer. If you are trying to control the itch and swelling, cold compresses and elevation will be very helpful.