sideEffects

Side effects are unintended effects that accompany a drug or medical treatment and occur in addition to the intended therapeutic effect. They can be mild or serious and may be dose-related or time-limited. The term is often used to describe effects not central to the primary goal of treatment; regulatory and clinical usage sometimes distinguish side effects from adverse effects, which are harmful or undesired outcomes. In practice, the line between the two can vary by context and monitoring.

Occurrence and risk depend on the medication and the person. Factors include dose, route of administration, duration of therapy, age, sex, genetics, liver or kidney function, and interactions with other medicines or foods. Some side effects are predictable and common; others are rare or idiosyncratic. Side effects can begin soon after starting therapy or emerge after weeks of exposure.

Examples vary by class. Analgesics often cause stomach upset or drowsiness; antibiotics may cause diarrhea; antihypertensives can cause dizziness or cough; antidepressants may alter sleep or sexual function; chemotherapy can produce fatigue, nausea, and nail changes. Serious adverse effects, though uncommon, include severe allergic reactions or organ injury, and require urgent medical attention.

Management focuses on informed choice, monitoring, and balancing benefits and risks. Clinicians may adjust the dose, switch medicines, or provide supportive care. Patients should report persistent or severe side effects, and pharmacovigilance programs collect safety data to improve treatment guidance and labeling.