- Traumatic (pathology from injury)
External source (destructive physical injury; e.g., motor vehicle accident)
Internal source (effects of high blood pressure on arterial walls) - Toxic (pathology from poisons)
Biological toxins (snake venom)
Chemical/physical toxins (toxic chemicals, radiation) - Hemodynamic/vascular (pathology from disorders of blood vessels)
Ischemic (decreased blood supply to an organ or tissue; e.g., stroke or heart
attack)
Hemorrhagic (excessive bleeding from a ruptured blood vessel; e.g., ruptured
aneurysm) - Hypoxic (pathology from inadequate supply or excessive demand for oxygen by a
tissue)
Generalized/organ specific (lung disease, anemia, decreased blood supply)
Cellular hypoxia (cyanide poisoning of electron transport chain in mitochondria) - Inflammatory (pathology from abnormal inflammatory response in the body)
Autoimmune and/or chronic diseases (systemic lupus erythmatosus, rheumatoid
arthritis)
Response to environmental triggers (asthma) - Infectious (pathology from microbes or infectious agents)
Prions, viruses, bacteria, fungi, parasites (pneumonia, meningitis, gastroenteritis) - Neoplastic (pathology from tumors, cancer)
Carcinoma (adenocarcinoma of the breast)
Sarcoma (osteogenic sarcoma) - Nutritional (pathology from too much/too little food intake)
Deficiency (vitamin deficiency secondary to reduced intake)
Excess (obesity leading to diabetes) - Developmental (pathology in the chemistry of heredity)
Inborn errors of metabolism (Fanconi’s syndrome, cystinuria)
Genetic diseases (Huntington’s disease) - Degenerative (pathology from age-related tissue breakdown)
Protein misfolding diseases (Alzheimer’s dementia, prion diseases)
Apoptosis (pre-programmed cell death)
Mechanical “wear-and-tear” (osteoarthritis [or, more correctly, osteoarthropathy])
This classification system is based on a traditional pathology approach to disease
with emphasis on etiology(causative factors) and pathogenesis(mechanism of disease,
particularly at a cellular level). There are strengths and weaknesses in this system as
well. The strengths are many. For example, drug design that targets neoplasia may lead
to drugs with many applications, including lung cancer, bowel cancer, or brain cancer.
Likewise, drug design that targets inflammation could have applications to many dif-
ferent diseases, affecting many organ systems. Nevertheless, this approach focuses
more on cellular targets than on molecular targets.
BIOCHEMICAL CONSIDERATIONS IN DRUG DESIGN 187