Zyrtec stomach. . If any of these effects persist or . It may also be used to treat hives. How to use Zyrtec Oral. will send it to people & experts who can help. . . . List of 385 disease causes of Stomach ache, patient stories, diagnostic guides, medical books excerpts online about Stomach ache, 6 drug side effect causes. Stomach Cramps: Less Severe: Nervous: Less Severe: Confused: Less Severe: Over Excitement. . . . Adults taking Zyrtec may experience drowsiness and dry mouth. Zyrtec sho... more