Antimicrobial Agents Flashcards
(34 cards)
__azole
Antifungal Agent
Reduces ergosterol synthesis by inhibiting fungal cytochrome p-450 enzymes. Also inhibits mammalian p-450. Rx for Blasto, Coccidio, Histo. SE: GI upset, abnormal LFTs.
Ex: Ketoconazole: broad-spectrum for Asper, Mucor, Candida. Disrupted gonadal/adrenal steroid synthesis = Rx for Cushings and prostate CA, can cause gynecomastia, decreased libido, menstrual irregularities. Miconazole and Clotrimazole: toxic, only topical use.
Ex: Fluconazole, Itracon-, Voricon-: Systemic Cryptococal meningitis and Candida sepsis. NO disruption of steroid synthesis.
Flucytosine
Antifungal Agent
Nucleotide analog that inhibits thymidylate synthetase, which inhibits DNA/RNA synthesis.
Used in combo with others (Amph. B) for systemic Cryptococcus and Candida. SE: bone marrow suppression, hepatotoxicity.
Capsofungin: inhibits glucan synthetase to disrupt cell wall, used for systemic Candida and Aspergillosis.
Amphotericin B, Nystatin
Antifungal
Binds ergosterol, punches hole in membrane via change in permeability.
Rx: SYSTEMIC mycosis, give intrathecally w/fungal meningitis. SE: nephrotox, infusion-related rxn (fever, chills, muscle spasm, HA), abnormal LFTs.
Nystatin: oral and cutaneous candidiasis (toxic).
Griseofulvin, Terbinafine
Antifungal
Interferes with microtubule function in keratin-rich tissue to inhibit replication.
Rx for topical dermophytic infections, take orally. SE: HA, confusion, GI upset, allergic rxn, hepatitis.
Terbinafine: inhibits qualene epoxidase to inhibit ergosterol synthesis. Same indications.
__cillin
Penicillins: Beta-Lactam Antibiotic
Inhibits cell wall synthesis by binding PBP to block peptidoglycan cross-linking.
SE: Allergic rxn, Coombs + hemolytic anemia (Pen), nonallergic skin rash and diarrhea (Amp, Amox), interstitial nephritis (Me), neutropenia (Naf), Hepatitis (Ox).
Ex: Penicillin, Methicillin, Piperacillin, Amoxicillin, Ampicillin.
Others: Aztreonam (no allergy, rash, elevated LFTs, GI upset), Imi/Meropenem (GI upset, rash, seizures) - Imi needs Cilastatin.
Ceph__, Cef__
Cephalosporins, Beta-Lactam Antibiotic
Inhibit cell wall synthesis by binding PBP to block peptidoglycan cross-linking.
SE: hypersensitivty rxn (10% with penicillin allergy), disulfiram-like rxn, nephrotoxicity.
Ex: Cephalexin, Cefuroxime, Ceftriaxone.
__mycin
Aminoglycosides, Protein Synthesis Inhibitor Antibiotic
30S, inhibits initiation complex and causing mRNA misreading. Severe gram negative rod infections.
SE: nephrotoxicity (ATN with cephalosporins), ototoxicity (with loop diuretics), teratogen.
Ex: Gentamicin, Neomycin, Mikacin, Tobramycin, Streptomycin.
__cycline
Tetracyclines. Protein Synthesis Inhibitor Antibiotic
30S tRNA, prevents attachment of tRNA to ribosome.
SE: Teeth discoloration and bone deformity in children, teratogen, GI upset, photosensitivity, dizziness, Fanconi syndrome (aminoaciduria, phosphaturia, acidosis, glycosuria). Avoid taking with divalent cations (milk, iron, antacids), inhibit absorption.
Ex: Tetracycline, Doxycycline, Minocycline, Demeclocycline (SIADH Rx, antagonist at V2 receptors).
__thromycin
Macrolides: Protein Synthesis Inhibitor Antibiotic
50S tRNA, blocks translocation and inhibits formation of initiation complex. SE: GI upset, acute cholestatic hepatitis, skin rash, eosinophilia.
Ex: Erythromycin (inhibits P-450), Clarithromycin, Azithromycin.
Others: Chloramphenicol (peptidyl transferase inhibitor - causes aplastic anemia, gray baby syndrome), Clindamycin (pseudomembranous colitis, nausea, diarrhea, skin rash, impaired liver fxn), Linezolid (ribosome complex formation inhibitor).
Sulfa__
Sulfonamide Antibiotics
Inhibit folic acid synthesis by inhibiting dihydrofolate reductase, leading to disrupted DNA synthesis.
SE: allergic rxn (Steven-Johnson syndrome), hemolytic anemia, kernicterus in newborns, granulocytopenia (give folinic acid), nephrotoxicity.
Ex: Trimethoprim/Sulfamethoxazole (PABA analog) (TMP/SMX), Sulfisoxazole, Sulfamethizole, Sulfadoxine, Sulfadiazine.
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__floxacin
Fluroquinolone Antibiotics
Inhibit DNA gyrase topoisomerase2, inducing DNA strand breakage and death.
SE: tendonitis, tendon rupture, GI upset, skin rash, HA, dizziness. Contraindicated in pregnancy and children (damage cartilage).
Ex: Moxifloxacin, Ciprofloxacin, Levofloxacin.
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Vancomycin
Antibiotic
Binds D-ala D-ala terminus of cell wall precursors, inhibiting transglycosylase, leading to weakened proteins in cell wall and cell lysis.
Rx for serious gram positive infections (sepsis, MRSA, C. diff, endocarditis). SE: oto/nephrotoxicity, Red Man Syndrome (flushing, prevent with slow infusion and antihistamines).
Polymyxins: increase permeability of cell membranes, but very toxic. Only topical use for skin lesions infected with gram negative rods.
Metronidazole
Antibacterial and Antiprotozoan agent
Reduces to reactive compounds, overall damage/death.
Rx for anaerobic infections below the diaphragm, protozoans (Giardia, Entamoeba, Trichomonas, Gardenerella), and H. pylori with Bismuth and Amoxicillin or Tetracycline. SE: HA, metalic taste, disulfiram-like effect.
Rifampin
Antimycobacterial Agent
Inhibits DNA dependent RNA pol/synthesis. Prophylaxis for N. meningitis and H. flu B, used in combination for Leprosy and TB Rx. SE: Orange secretions/urine, hepatitis, nephritis, rash, thrombocytopenia. Induces P-450.
Rx for TB for 6 months.
Isoniazid
Antimycobacterial Agent
Inhibits mycolic acid synthesis. Prophylaxis for contacts of active TB patients. SE: neurotoxicity (give Vitamin B6), induces lupus, hepatitis, G6PD hemolytic anemia. Some pts are fast metabolizers, so watch drug levels.
Rx for TB for 6 months.
Pyrazinamide
Antimycobacterial Agent
MOA unknown. Sx: hepatotoxicity, GI intolerance, fever, hyperuricemia (gout).
Rx for TB for 2 months.
Ethambutol
Antimycobacterial Agent
Inhibits arabinosyl transferase, disrupting cell wall synthesis. SE: retrobulbar neuritis leading to visual disturbances and red/green blindness.
Rx for TB for 2 months (6 if Isoniazid resistant).
Dapsone
Antimycobacterial Agent
PABA antagonist that inhibits folate/DNA synthesis. SE: hemolytic anemia in G6PD, GI intolerance, rash.
Prophylaxis for PCP, use with Rifampin and Clofazimine for Rx of Leprosy.
__quin__
Antimalarial Agent
Chloro concentrates in vacuoles and prevents heme metabolism, causing toxicity and death. Others MOA unknown.
SE: C - Gi upset, pruritis, visual disturbances, EKG changes. Q - cinchonism (tinitus, HA, dizziness, nausea), Coombs + hemolytic anemia, contraindicated in pregnancy b/c toxic to fetus. M - mental status changes, GI upset, cardiac abnormalities. P - hemolytic anemia in G6PD, abdominal pain, contraindicated in pregnancy b/c fetal hemolytic anemia.
Ex: Chloroquine (prophylaxis), Mefloquine and Quinine (resistant forms), Primaquine (latent hepatic vivax/ovale).
Pentamidine, Nifurtimox, Suramin, Melarsoprol, Sodium Stibogluconate
Antiprotozoan Agents
Pentamidine: inhibits RNA synthesis. Alt Rx for T. brucei (African Sleeping Sickness), PCP pro.
Nifurtimox: generates free radicals. Rx for Chagas.
Suramin: inhibits energy metabolism enzymes. Rx for early T. brucei.
Melarsoprol: inhibits enzymes. Rx for late/CNS T. brucei.
Sodium Stibogluconate: inhibits glycolysis. Rx of Leishmaniasis.
Mebendazole
Antihelminthic Agent
Inhibits microtubule synthesis/fxn. Rx for Whipworm, Hookworm, Pinworm, Roundworm (Trichinella, Ascaris 2nd).
Whipworm (Trichuris): asymptomatic, bloody diarrhea. Get from dried goods. White bodies hanging from inflamed mucosa, barrel-shaped eggs in stool. Treat with Mebendazole.
Hookworm (Necator/Ancylostoma): pneumonia, gastroenteritis, anemia. Get from barefoot and invade blood, eggs in stool. Give iron and folic acid for anemia. Cat and dog hookwarm cause cutaneous larva migrans due to inability to invade blood. Rx with Mebendazole, Pyrantel Pamoate.
Thiabendazole
Antihelminthic Agent
Inhibits microtubule synthesis/fxn. Rx for Roundworm (Strongyloidiasis, Trichinella), cutaneous larva migrans.
Roundworm (Strongyloidiasis): Diarrhea and eosinophilia, pneumonia, diffuse superinfection in immunodeficient, peritonitis. Get from barefoot and invade blood, larve in stool, string test for duodenal larvae. Rx with Thiabendazole, Ivermectin.
Roundworm (Trichinella spiralis): in pig meat, form cysts with larvae in muscle (myocarditis, no Rx), gastroenteritis, myalgia (give steroids), encephalitis if severe. Rx with Me/Thiabendazole.
Albendazole
Antihelminthic Agent
Inhibits microtubule synthesis/fxn. Rx for Tapeworm (Dog, Pork [tissue] 2nd), Pinworm, Roundworm (Ascaris 2nd), cutaneous larva migrans.
Echinococcus granulosus (Dog Tapeworm): hyatid cysts in lung, liver, brain. Expansion causes organ displacement, daughter cysts with eggshell calcifications, inject with ethanol to prevent anaphylaxis and resect. Rx with Albendazole.
Pinworm (Enterobius): most common in kids, perianal itching, Scotch tape test for eggs. Fecal-oral from contaminated surfaces. Rx with Me/Albendazole, Pyrantel Pamoate.
Pyrantel Pamoate
Antihelminthic Agent
Activates nicotinic receptors, paralysis. Rx for Roundworm, Hookworm, Pinworm 2nd.
Roundworm (Ascaris): most common helminth overall, rough eggs, obstruction/pneumonia, malnutrition, asymptomatic. Fecal-oral transmission from soil, hatch in small gut, invade lungs via blood, coughed up and swallowed, mature in GI. Rx with Pyrantel Pamoate, Me/Albendazole.
