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1、Chemistry for Changing Times11th EditionHill and KolbChapter 19DrugsJohn SingerJackson Community College,Jackson,MI 2007 Prentice Hall1Chemical Cures,Comforts,and CautionsDrugs are defined as any chemical substance that affects the function of living things and is used to relieve pain,treat illness,
2、or improve health or wellbeing.Drugs can be obtained from plant sources,microorganisms,marine organisms,and synthetic sources.2Scientific Drug DesignPaul Ehrlich determined that certain drugs are more toxic to disease organisms than to human cells.He first coined the term chemotherapy and was awarde
3、d the Nobel Prize in medicine/physiology in 1908.3Pain Relievers:Nonsteroidal Anti-Inflammatory Drugs(NSAIDS)NSAIDS relieve pain and reduce inflammation by blocking the production of prostaglandins.NSAIDS include aspirin,ibuprofen,acetominophen,etc.4Pain Relievers:Nonsteroidal Anti-Inflammatory Drug
4、s(NSAIDS)Aspirin for Heart Attack and Stroke PreventionNSAIDS block the production of prostaglandins,some of which are responsible for blood clotting.This is the source of their anticoagulant properties.Many adults take daily small doses of aspirin(81 mg)to help prevent heart attack and stroke.5Pain
5、 Relievers:Nonsteroidal Anti-Inflammatory Drugs(NSAIDS)NSAIDS and Fever ReductionFevers are caused by compounds called pyrogens that are released from leukocytes and other circulatory cells.Pyrogens often use prostaglandins as secondary messengers.Since NSAIDS block the production of prostaglandins,
6、they help to reduce fever.6Pain Relievers:Nonsteroidal Anti-Inflammatory Drugs(NSAIDS)How NSAIDS WorkCycloxygenase(COX)enzymes catalyze the production of prostaglandins from arachidonic acid.Two COX enzymes are known to exist:COX-1 found in the stomach and kidney tissues,and COX-2 found in tissues w
7、here inflammation occurs.Aspirin,ibuprofen,and naproxin block both COX enzymes.Blocking COX-1 enzyme leads to the side effects of excessive bleeding and stomach pain.7Pain Relievers:Nonsteroidal Anti-Inflammatory Drugs(NSAIDS)How NSAIDS Work Newer NSAIDS only block the COX-2 enzyme and do not experi
8、ence the side effects of the older NSAIDS.Unfortunately,some have side effects of increased risk of heart attack and stroke as well as allergic reactions and internal bleeding.8Pain Relievers:Nonsteroidal Anti-Inflammatory Drugs(NSAIDS)AcetominophenAcetominophen helps reduce pain and fever.It is not
9、 anti-inflammatory and it is not an anticoagulant.It appears to act by blocking the COX-3 enzyme.Acetominphen can be taken by those affected by aspirin side effects and children.However,when taken with alcohol it can cause liver and kidney damage.9Pain Relievers:Nonsteroidal Anti-Inflammatory Drugs(
10、NSAIDS)Combination pain relievers can include a number of different NSAIDS as well as caffeine,antihistamines,and other drugs.Excedrin and Anacin are familiar brands.10Chemistry,Allergies,and the Common ColdA variety of cold and allergy medications are available over-the-counter.Colds are caused by
11、more than 200 different viruses.There are no effective cures.Most cold medications treat only the symptoms.Periodically the FDA reviews these medications for safety and effectiveness.11Chemistry,Allergies,and the Common ColdAntihistamines relieve the symptoms of allergies caused by the actions of hi
12、stamine.Histamines are released by certain cells when an allergen binds to its surface.Histamines cause redness,swelling,and itching.12Chemistry,Allergies,and the Common ColdCough suppressants(antitussives)include two narcotics:codeine and dextromethorphan.In addition,the antihistamine diphenhydrami
13、ne has been found to be effective by the FDA.13Chemistry,Allergies,and the Common ColdExpectorants help to bring up mucus from the bronchial passages.Only one expectorant,glyceryl guaiacolate(guaifensin),has been found to be marginally effective.Decongestants are inhaled through the nasal passage.Th
14、ey seem to be safe and effective for occasional use.They include oxymetaxoline,xylometaxoline,naphaxoline,and phenylephrine.14Antibacterial DrugsIn 1900,infectious disease was a leading cause of death.15Antibacterial DrugsSulfa drugs were the first antibacterial drug.Sulfanilamide acts by replacing
15、para-aminobenzoic acid that bacteria need to manufacture folic acid.16Antibacterial DrugsPenicillins are antibiotic substances.Antibiotics are soluble substances derived from molds or bacteria that inhibit the growth of other microorganisms.Penicillins work by inhibiting the enzymes that bacteria us
16、e to make their cell walls.17Antibacterial DrugsCephalosporinsBacteria have evolved resistances to certain antibiotics.Scientists are working to develop new and more potent antibiotics to kill resistant bacteria.Penicillins have been partially replaced by cephalosporins such as cephalexin(Keflex).18Antibacterial DrugsTetracyclines are broad-spectrum antibiotics that act by binding to bacterial ribosomes inhibiting protein synthesis.19Antibacterial DrugsFluoroquinolones are broad-spectrum antibio
