What medication can effect an ETG test?

Answer 1

According to the Substance Abuse and Mental Health Services Administration (SAMHSA):

...the extent of false positives is unknown, but alcohol is often in medications, hygiene products, cosmetics, foods, etc. Research is needed to determine whether incidental alcohol exposure can substantially influence the biomarkers.

They further state:

Currently, the use of an EtG test in determining abstinence lacks sufficient proven specificity for use as primary or sole evidence that an individual prohibited from drinking, in a criminal justice or a regulatory compliance context, has truly been drinking. Legal or disciplinary action based solely on a positive EtG, or other test discussed in this Advisory, is inappropriate and scientifically unsupportable at this time. These tests should currently be considered as potential valuable clinical tools, but their use in forensic settings is premature.

However, we doubt that whoever is using this as a screening test has read (or cares) about SAMHSA's opinion, so we would stay away from anything containing alcohol, including over the counter medications. We can find no prescription medications that will react positively, but many of them are prepared in alcohol solutions, so be careful.

Source: "ADVISORY: Substance Abuse Treatment News for the Treatment Field", September 2006 Volume 5 Issue 4 "The Role of Biomarkers in the Treatment of Alcohol Use Disorders"

http://www.kap.samhsa.gov/products/manuals/advisory/pdfs/0609_biomarkers.pdf