Toxicologie

Drug toxicology is the branch of toxicology that studies the harmful effects of drugs and pharmaceutical substances on living organisms.

Definition (exam-ready)

Drug toxicology evaluates the toxic effects, safe dosage limits, mechanisms of toxicity, and adverse reactions of drugs used for medical or non-medical purposes.

Main objectives

• Determine safe and toxic doses

• Identify adverse drug reactions (ADRs)

• Study mechanisms of drug toxicity

• Prevent drug poisoning and overdose

• Support drug approval and regulation

Major areas of drug toxicology

1. Acute toxicity

   • Effects after a single or short-term exposure

   • Example: paracetamol overdose

2. Chronic toxicity

   • Effects after long-term use

   • Example: kidney damage from prolonged NSAID use

3. Organ-specific toxicity

   • Hepatotoxicity (liver)

   • Nephrotoxicity (kidneys)

   • Neurotoxicity (nervous system)

   • Cardiotoxicity

4. Reproductive and developmental toxicity

   • Effects on fertility and pregnancy

5. Genotoxicity and carcinogenicity

   • DNA damage and cancer risk

Common causes of drug toxicity

• Overdose

• Drug–drug interactions

• Improper metabolism

• Individual sensitivity (age, genetics, disease)

• Long-term misuse

Examples of toxic drugs

• Paracetamol → liver toxicity

• Aminoglycosides → kidney and ear toxicity

• Chemotherapy drugs → bone marrow suppression

• Opioids → respiratory depression

Importance of drug toxicology

• Ensures patient safety

• Guides clinical dosing

• Helps in poison management

• Supports pharmacovigilance systems