Most medicines, over-the-counter and prescription, including birth control pills and antibiotics, should not affect the results of a home pregnancy test. Only medicines that have the pregnancy hormone hCG in them can give a false positive test result. A false positive is when a test says you are pregnant when you’re not.
Sometimes medicines containing hCG are used to treat infertility (not being able to get pregnant). Alcohol and illegal drugs do not affect HPT results. But women who may become pregnant should not use these substances.