Adverse events: A polite scientific term for “the bad things that could happen to you as a result of a medical therapy.” Found most often in clinical reports on drugs, the term is synonymous with “side effects.” Adverse events caused by HIV meds can range from short-term (nausea, headaches) to long-term (body-shape changes). Luckily, there are remedies to ease or eliminate many side effects and make adverse events a nonevent.