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Chemotherapeutic Drugs

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rhawkie's version from 2016-10-25 15:34

Inhibitors of...

Question Answer
Cell wall synthesisB-Lactams, glycopeptides
Folic acid synthesisSulphonamides
Nucleic acid synthesisQuinolones, metronidazole
Protein synthesisMacrolides, tetracyclines, aminoglycosides
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Penicillins (B-Lactams (Inhibits CWS))

Question Answer
Penicillin G> Narrow, G+ <> Tonsillitis, pharyngitis, syphillis <> Gastric-labile, B-Lactamase sens. <> IV & IM <> Hypersens. (5-10%), upset GIT, Superinf, Nephritis, Neurotox <> Preg = B
Penicillin V> Narrow, G+ <> Proph. of Rheumatic Fever <> 2-4 times less active than Pen. G, B-Lactamase sens. <> Oral <> Same as Pen. G <> Preg = B
Cloxacillin> Gram + Staph <> Staph inf <> Acid-stable, decreased absorption with food <> Mainly Oral <> Same as Pen. G <> Preg = B
Amoxicillin> Broad - G+ & G- <> Influenza, Otitis, Resp. tract inf <> Acid-stable, B-Lactamase sens <> Oral, IV <> Same as Pen. G <> Preg = B
Ampicillin> Broad - G+ & G- <> Influenza, Salmonella, Shigella <> Acid-stable, not with food, B-Lactamase sens <> Mainly IV & IM, also orally <> Same as Pen. G, diarrhea <> Preg = B
Co-Amoxiclav> Broad = G+ & G-, anaerobes <> UTI, Bites <> Clav. acid protects against B-Lactamase <> Oral <> GIT <> Preg = B
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Cephalosporins (B-Lactams (Inhibits CWS))

Question Answer
Cephazolin (1st Gen)> Broad, worst G- cover <> Surgical Prophylaxis <> Acid-stabile, but poor absorption from GIT <> Mainly IV & IM <> Hypersensitivity (Cross with pen (<2%)), SJS, superinfection, upset GIT <> Preg = B
Cefuroxime (2nd Gen)> Broad (Good alt to Genta) <> Pneumonia, Bonchitis, Sinusitis, Otitis (pen pref) <> Acid-stabile, but poor absorption from GIT <> Oral <> Same as Cephazolin <> Preg = B
Ceftriaxone (3rd Gen)> Broad (Good alt to Genta) <> Pneumonia, meningitis, gonorrhea <> Acid-stabile, but poor absorption from GIT, Penetrates CSF <> IV <> Same as Cephazolin <> Preg = B
Cefepime (4th Gen)> Broad (Good alt to Genta), except co-amoxiclav-resist Staph <> Pneumonia, Meningitis (not Listeria) <> Acid-stabile, but poor absorption from GIT, Penetrates CSF <> IV <> Same as Cephazolin <> Preg = B
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Carbapenems (B-Lactams (Inhibits CWS))

Question Answer
Imipenem> Broad (Not clox-resist staph) <> Severe hospital inf only <> Not absorbed orally, hydrolyzed by dipeptidase in renal tubule (administer with cilastatin) <> IV <> Same as other B-Lactams <> Preg = B
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Glycopeptides (Inhibits CWS)

Question Answer
Vancomyin> G+ <> MRSA (if resist. to clox as well), endocarditis, sepsis <> Binds with high aff. to D-alanyl-D-alanine terminal of peptidoglycan pentapeptide <> IV <> Red-man syndrome (hypotension, flushing, NOT allergic (caused by rapid IV)), oto- & nephrotoxicity, hypersens <> Preg = C
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Sulphonamides (Inhibits folate metabolism)

Question Answer
Co-trimoxazole (combo of 2 antimetabolites (sulphamethoxazole & thimethoprim))> Resist common <> Proph of oppertunistic inf in immunocomp. <> Well absorbed, widely distributed <> Oral <> Prolonged use: folate def., megaloblastic anaemia, Hypersens, SJS <> Preg = B
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Fluoroquinolones (Inhibits DNA synthesis (blocks topoisomerase II)

Question Answer
Ciprofloxacin> Same as Aminoglycosides, G- <> UTIs (MDR strains) <> Wide distribution (bone,kidney,prostate,lung) <> Oral, also IV <> Tendon rupture, prolonged QT interval <> Avoid during preg and <18 years
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Nitroimid

Question Answer
Metronidazole> Anti-protozoal (entamoeba, trichomonas, H. pylori) <> colonic inflm, amoebic dysentry, liver abscess, vaginitis, urethritis, peptic ulcer, STIs <> Widely distributed, also CSF <> Orally, also IV & rectal <> Metallic taste, minor GIT, interferes with alcohol metabolism <> Avoid during preg, mutagenic, carcinogenic, teratogenic, not >10 days
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Aminoglycosides (Inhibits protein synthesis)

Question Answer
Gentamicin (30s)> Limited G+, P. aeruginosa, lifethreatening aerobic G- <> endocarditis, bacteremia, sepsis, UTI <> Highly polar, used in combos <> IM, not orally <> Nephro- & ototoxicity, vestibular damage, neuromuscular block, tremor, fever, rash, hepatic damage <> Preg = C, <60 years
Amikacin (30s)> Limited G+, P. aeruginosa, lifethreatening aerobic G- <> endocarditis, bacteremia, sepsis, UTI <> Highly polar, used in combos, used with metronidazole/clindamycin for anaerobic <> IM, not orally <> Same as Gentamicin <> Preg = D
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Tetracycline (Inhibits protein synthesis)

Question Answer
Doxycycline (30s)> Broad <> Tick bite fever, malaria prophylaxis <> Lipid-soluble, well absorbed <> Oral, avoid food <> GIT, Ca2+ complexes deposited in new bone and teeth <> Preg = D, <8 years
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Macrolides (Inhibits protein synthesis)

Question Answer
Eryrthromycin (50s)> Same as Pen. G, legionella, bordetella, mycoplasma, chlamydia <> Good alt for Pen. allergic patients <> Acid-labile (needs enteric coating), widely distributed, crosses placenta, but not BBB, CP450 inhibition <> Oral, IV <> GIT, Prolonged QT interval <> Preg = B
Azithromycin (50s)> Same as Pen. G, chlamydia, atypical pneumonia, STIs, syndromic management <> No CP450 inhibition, long t1/2, Crosses placenta, not BBB <> Oral with enteric coat <> Lower GIT side-effects <> Preg = B
Clindamycin (50s)> Used when doxycycline not indicated <> Oral inf, lung abscess, necrotizing fasciatis <> Penetrates most tissues, not CSF or ICF, hepatic metabolism <> Oral, IV <> GIT, fever, rash, clostridium difficile enterocolitis (6%)
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Amphenicol (Inhibits protein synthesis (inhibits peptidyltransferase enzyme))

Question Answer
Chloramphenicol (50s)> Broad <> Meningitis, Rickettsia, Eye inf <> Rapidly absorbed GIT, widely distributed (CSF as well), metabolized by liver <> IV, IM <> Depression of bone marrow <> Grey baby syndrome (40% mortality)
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Antimycobacteria (Used as first line defense against mycobacteria)

Question Answer
Ethambutol> Inhibits arabinogalactan synthesis <> Protects against resistance in TB therapy <> Poor CNS penetration <> Oral <> retrobulbar neuritis, hyperuricaemia <>
Isoniazid> Inhibits mycolic acid synthesis <> Rapidly dividing bacilli <> Penetrates and distributes well <> Oral <> peripheral neuropathy <>
Pyrazinamide> Bactericidal in acid <> Intracellular phagosomes <> Penetrates well, active at low pH <> Oral <> Hepatotoxic, hyperuricaemia, hypersensitivity <>
Rifampicin> Inhibits DNA polymerase <> Slow-growing bacilli <> Variable bioavailability, widely distributed <> Hepatitis, hypersensitivity, skin eruption, flu symptoms, GIT <>
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Antifungals

Question Answer
Amphotericin B (ergosterol)> Broad <> First line for systemic fungal inf, cryptococcal meningitis <> Insoluble in H2O, crosses inflamed meninges, excreted slowly <> IV, topical <> Fever, headache, GIT
Ketoconazole (CP450 of fungal cells)> Yeast <> No longer used systemically <> Widely distributed <> Topical (replaced by fluconazole) <> Hepatotoxic, infertility, menstrual irregularities
Fluconazole (CP450 of fungal cells)> Candida, cryptococcus <> Candidiases, cyptococcal meningitis <> Crosses BBB <> IV <> GIT, headache
Griseofulvin (Inhibits mitosis)> dermatophyte inf <> inf of skin, hair, nails <> Absorption increased by fatty meal <> Oral <> GIT, Headache
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Antivirals

Question Answer
Acyclovir> Inhibits DNA synthesis <> HSV, VZV, Glandular fever <> Widely distributed (CSF as well) <> Oral, IV, Topical <> GIT, headache <> Dehydration
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Nucleotide Reverse-Transcriptase Inhibitors (Retroviruses e.g. HIV)

Question Answer
Tenofovir> Adenosine analogue RT inhibitor <> Mimics DNA building blocks and terminates DNA prematurely <> Oral <> Renal toxicity <> Pre-existing renal disease
Emtricitabine> Non-Thymadine analogue <> Mimics DNA building blocks and terminates DNA prematurely <> Oral <> Diarrhea, peripheral neuropathy
Lamivudine> Non-Thymadine analogue <> Mimics DNA building blocks and terminates DNA prematurely <> Oral <> Diarrhea, peripheral neuropathy
Zidovudine> Thymadine analogue <> Mimics DNA building blocks and terminates DNA prematurely <> Oral <> Nausea, Headache, Anaemia
Stavudine> Thymadine analogue <> Mimics DNA building blocks and terminates DNA prematurely <> Oral <> Hepatitis. peripheral neuropathy, lipoatrophy
Efavirenz> RT inhibitor <> CP450, given before sleep <> Oral <> Abnormal dreams, difficulty concentrating, dizziness, insomnia, depression, rash <> Teratogenic, Preg = D
Nevirapine> RT inhibitor <> Oral <> Skin rash <> Hepatitis <> Not combined with TB rx
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Antimalarials