Which of the following can be a side effect of cardiac medications?

Weight gain is a well-documented side effect of certain cardiac medications. Many heart-related treatments, such as specific beta-blockers and calcium channel blockers, can lead to changes in metabolism and fluid retention, which may cause patients to experience an increase in weight. Some medications can also impact appetite or lead to hormonal changes that contribute to weight gain.

In contrast, the other options—feeling energized, improved vision, and increased stamina—are not common side effects associated with cardiac medications. While patients may experience improved overall well-being or physical capability as their cardiac conditions are managed more effectively over time, these are not directly caused by the medications themselves. Additionally, many cardiac medications are associated with fatigue or a decrease in energy levels, rather than feelings of increased energy. Thus, the choice of weight gain as a side effect directly aligns with the known impacts of particular cardiac drugs.