What effect can result from drugs acting on unintended organs?

Drugs can influence various organs and systems in the body, and when they affect unintended organs, the most common result is the manifestation of side effects. Side effects are not the primary therapeutic effects that the medication is intended to produce; instead, they arise from the drug's interaction with different receptors and systems than those primarily targeted.

For instance, a medication designed to treat hypertension may inadvertently lead to side effects such as fatigue or dizziness, which occur due to its effects on organs other than the blood vessels. These side effects can range from mild to severe but are typically predictable based on the drug's pharmacological profile.

In contrast, adverse effects generally describe more significant and undesirable outcomes, which can be caused by side effects but often reflect a more harmful outcome. Toxic reactions refer to severe, harmful responses that can occur when a drug concentration exceeds safe levels, while allergic reactions involve the immune system's abnormal response to a drug, which is independent of its intended effect on organs. Therefore, the correct understanding of the consequences of drug interactions with unintended organs primarily aligns with the concept of side effects.