Chapter 11 Drugs to Treat Infections and Cancer
Evil Spirits, Bad Blood, Punishment of the Gods No, Just a little living creature trying to make its way in the world!
Why Does the Immune System Fail? Evolution Immune deficiencies –Genetic diseases –Drugs –HIV
Types of Infections Prions Viruses Bacteria Fungi Parasites
Prevention Soaps Antiseptics Disinfectants Physical Methods –Heat –Light
Antibiotics Small molecule differences Large molecule differences Specificity
Viral Infections Genetic material A few proteins Species and tissue specific Wide range Drugs Selectivity
Bacteria Complete form of life Genetic material: circular double stranded DNA plus plasmids Infections: –Extracellular: eg strep, menengitis –Intracellular: eg. tuberculosis, leprosy
Antibiotics Interfere with reproduction until the immune system cuts in Kill Similarities to and difference from human cells
Sulfonamides The first Synthetic Prontosil Liver conversion to sulfonamide Prevents reproduction (pABA and folic acid synthesis) Resistance
Sulfonamides cont. Oral administration Free and bound drug Kidney toxicity Liver toxicity Bone marrow suppression Allergy
Warfare Amongst the Microbes Microbes compete for resources Plants protect themselves Most antibiotics we find in nature Much of resistance exists in nature
Penicillin Made by a fungus Bacterial cell wall Fungal infections Penicillinase Allergy derivatives
Other Antibiotics hundreds Common Problems –Liver –Kidney –Bone marrow suppression –Resistance >Some unique Problems, eg Streptomycin
Fungal Infections Bacteria provide some protection: competition for simple molecules Increasing because of immunodeficiency Drugs: most common interfere with ergasterol synthesis Kidney/liver toxicity
Parasitic Infections Unique and varied Malaria- female mosquito to human –Sporozoan –Intracellular parasite (Red Blood Cells) –Sickle Cell anemia and evolution
Other Parasites Pneumocystis pneumonia Lots of worms
Cancer Uncontrolled reproduction of some type of your cells What causes cancer Is it inherited? Treating cancer is a big selectivity problem