Side effects of major classes of drugs represent complex and multifaceted aspect of pharmacotherapy, requiring careful attention and proactive management strategies. Essentially, drug side effects pose significant challenge in clinical practice, needing vigilant monitoring and purposeful prevention. By understanding the mechanisms, manifestations and risk factors associated with major drug side effects, healthcare professionals can optimize patient safety and enhance treatment outcomes. Comprehensive patient assessment, individualized treatment planning, rational prescribing practices and regular monitoring are essential components of preventing and managing drug-related complications. Effective communication, patient education and shared decision-making, boost collaborative care, promote drug adherence and reduce incidences of drug abuse. Through ongoing research, pharmacovigilance efforts, and advances in personalized medicine, the medical community continues to strive towards safer and more effective patient-oriented pharmacotherapy.