Obviously keeping the number of medications given to patients to a minimum is the best way. Second, understanding that drugs interact with not only other drugs but food and herbal remedies which patients may be buying for themselves. Drug test interactions. Finally, drugs can interact with biochemical tests potentially leading to false positives and false negatives. One example is amiodarone. Amiodarone alters the results of thyroid-function tests, causing an increase in serum T4 and serum reverse T3, and a decline in serum T3 levels.