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Antibiotics
Antibiotics All
63
Pharmacology
Professional
02/24/2012

Additional Pharmacology Flashcards

 


 

Cards

Term
What are 5 common features of penicillins?
Definition

1) Water solubility

2) Low protein binding (more lipophilic drugs tend to be protein-bound)

3) Organic anions (renal secretory clearance by active transport)

4) High doses are well tolerated--this provides favorable concentrations in tissues (though can cause seizure in very rare cases).

5) Though toxicity is low, propensity toward allergy is relatively high due to the foreign chemical structure.

Term
Mechanism of Penicillins
Definition

Inhibition of transpeptidase which crosslinks third residue of N-acetylmuramic acid, L-Lysine to the terminal D-alanine residue of an opposite N-acetylmuramic acid.

Destabilizes cell wall which leads to osmotic pressure induced blebbing and eventual cell death.

Term

Penicillin G

and

Penicillin V

Definition

ROUTE: G -- parenteral. V -- oral.

USE: 1) Streptococci. Except pneumococcus which should be treated with a 3rd Cephalosporin until sensitivity is established). 2) Neisseria meningitidis. 3) Syphilis. 4) Oral anaerobes. 5) Actinomyces. 6) Clostridial gas gangrene.

Term

Methicillin

Oxacillin

Dicloxacillin

Nafcillin

Definition

GEN: Penicillinase-resistant beta-lactams produced in response to Staph. aureas penicillinase.

ROUTE: Oxa -- parenteral. Dicloxa -- oral.

USE: Penicillinase-resistant strains of Staph. aureas. Not a substitute for PenG where PenG can be used--not as effective (i.e. non-penicillinase producting Staph.).

TOX: Higher incidence of allergic interstitial nephritis.

Term

Ampicillin

Amoxicillin

Definition

Amino-penicillins.

ROUTE: Amp -- parenteral. Amox -- oral.

USE: Originally added E. coli, Salmonella, Shigella to spectrum, however now many are resistant. 1) Strep. -- particularly enterococci. 2) Mouth anaerobes.

3) Haemophilus/moraxella (70% sensitive). 4. E. coli (however, 50% sensitive).

DISEASES: Good for upper resp. pathogens. Otitis media in children due to pneumococcus resistance to PenG.

Term
Piperacillin
Definition

Extended-spectrum penicillin (Anti-pseudomonals).

USE: 1) Strep. 2) Oral anaerobes. 3) Haemophilus/moraxella. 4) E. coli (50% resistant). 5) Proteus species. 6) Klebsiella. 7) Serratia. 8) Enterobacter. 9) Pseudomonas.

OTHER: Broadest spectrum of all penicillins when combined with a beta-lactamase inhibitor (i.e. Tazobactam). Zosyn is pip-taz.

Term

Ampicillin/sulbactam

Piperacillin/tazobactam

Amoxicillin/clavulinate

Definition

Beta-lactamase inhibitors (suicide inhibitors)

USE: ONLY in combination with aminopenicillins or extended spectrum penicillins. Adds, Staph. aureas, gut anaerobes and all Haemophilus coverage to the above penicillins.

TOX: Immune-mediated thrombocytopenia.

Term

Cefazolin

Cephalexin (keflex)

Definition

1st Generation Cephalosporins. Cefazolin -- parenteral; Cephalexin -- oral.

USE: Staph. aureas, Strep. (except enterococci), E. coli, Proteus, Klebsiella, mouth anaerobes. Good gram (+) coverage; modest gram (-) coverage.

NO CNS PENETRATION.

ALLERGY: If penicillin allergy is rash, OK to use cephalosporin. If urticarial/anaphylactic, then no.

Term
Cefuroxime
Definition

2nd Generation Cephalosporin. Both oral and parenteral.

USE: Less Staph. aureas coverage than 1st gen. Same gram (-) coverage (E. coli, Proteus, Klebsiella, mouth anaerobes) but added Haemophilus including penicillinase producing strains. Anaerobes both above and below diaphragm.

 

Term

Ceftazadime

 

Definition

3rd gen. Cephalosporin. Parenteral.

USE: Less Gram (+) activity than 2nd gen. (Loss of Staph. coverage). Same coverage on Haemophilus. Covers all anaerobes. Broader Gram (-) coverage. ANTI PSEUDOMONAS. EXCELLENT CNS PENETRATION.

Term
Ceftriaxone
Definition

3rd gen. Cephalosporin. Parenteral.

USE: Less Gram (+) activity than 2nd gen. Some Staph. coverage; retains pneumococcus activity because mutant PBP does not bind ceftriaxone. Same coverage on Haemophilus. Covers all anaerobes. Broader Gram (-) coverage. NON-ANTI PSEUDOMONAS. EXCELLENT CNS PENETRATION. Ceftriaxone and Vancomycin used for suspected bacterial meningitis (to cover possible pneumococcus resistance).

Term
Cefepime
Definition

4th Generation Cephalosporin.

 

3rd gen. Cephalosporin. Parenteral.

USE: Less Gram (+) activity than 2nd gen. Same coverage on Haemophilus. Covers all anaerobes. Broader Gram (-) coverage. A little better coverage of Enterobacter, Citrobacter, Serratia than ceftazidime and piperacillin. EXCELLENT CNS PENETRATION.

Term
Imipenem
Definition

Carbapenem. Parenteral.

USE: Broadest spectrum of all beta-lactams. Does NOT cover MRSA. For use in ICU patients or those with multiple resistant infections.

TOX: Do NOT use in patients with Seizure disorders. Can cause seizure if not renally dosed. Cross allergenic with penicillins maybe.

Term
Aztreonam
Definition

Monobactam. Parenteral.

USE: Gram (-) bacilli including Pseudomonas. No gram (+); no anaerobes.

TOX: Similar to penicillins. NOT CROSS-ALLERGENIC WITH PENICILLIN.

Term
Vancomycin
Definition

Glycopeptide.

USE: ONLY Gram (+) aerobes and Gram (+) anaerobes. Treatment of MRSA, coagulase negative Staph. infections and enterococcus infections resistant to aminopenicillins. Also useful orally against metronidazole-resistant C. diff. colitis.

TOX: Red-man syndrome (Flushing, Tachycardia, Hypotension--infuse IV slowly). Ototoxicity, nephrotoxicity, immune-mediated thrombocytopenia.

Term
Fosfomycin
Definition

Phosphonic Acid derivative.

USE: Enterococcal UTIs.

 

Term
Daptomycin
Definition

Cyclic lipopeptide.

MECH: Binds to bacterial membranes causing depolarization, loss of membrane potential and cell death.

USE: Gram (+) cocci ONLY. For VRSA.

TOX: Rhabdomyolysis.

Term

Ciprofloxacin

Levofloxacin

Definition

IV or oral. 100% bioavailability.

MECH: Inhibition of DNA Gyrase (low conc.) and Topoisomerase 4 (high conc.).

USE: Gram (-) enterobacteriaceae. For UTIs that are resistant to beta lactams and sulfonamides. Levofloxacin has added pneumococcal action but less gram (-) coverage as a result.

TOX: Dose-dependent CNS toxicity (confusion, agitation, dizziness). QTc widening - PVT.

Term
Metronidazole
Definition

Nitroimidazole. Prodrug.

MECH: Anaerobes use different electron-transport components that donate an electron to metronidazole creating a highly reactive nitro radical killing susceptible pathogens.

USE: Anaerobic and microaerophilic bacteria and parasites. All anaerobic bacteria. Protozoa including amoeba, giardia and trichomonas. Also used in combo for H. pylori.

TOX: Dose-dependent CNS stimulation. Neurotoxic to fetus; NOT good for PREGNANT. NO ALCOHOL --inhibits aldehyde dehydrogenase--builds up acetaldehyde.

Term

Streptomycin

Gentamycin

Tobramycin

Amikacin

Definition

Aminoglycosides.

MECH: Binds to 30S subunit of ribosome interfering with initiation of translation. Requires Oxygen for transport into bacterium therefore no action on anaerobes. Work synergistically with beta lactams.

USE: Gram (-) powerhouse Except anaerobes. Effective in sepsis due to rapid bacteriocidal effect, long post-antibiotic effect, poor tissue and CNS penetration (except kidney).

KINETICS: Very water soluble. Short half-life. 100% renal excretion--concentrates in tubular cells so dose carefully according to GFR.

TOX: Dose dependent Ototoxicity and nephrotoxicity. Enhances neuromuscular blockade and apnea--contraindicated in Myesthenia Gravis patients, guillan-barre and ventilator patients OR concominant use with neuromuscular blocking meds.

Term
Doxycycline
Definition

Tetracycline.

MECH: Reversably binds to 30S ribosomal subunit inhibiting tRNA from binding to the A site.

USE: Intracellular organisms: Mycoplasma, chlamydia, rickettsia. 85-90% effective against pneumococcus. Also re-emerging as MRSA skin infection treatment (85% eff.).

TOX: Skin photosensitivity--may cause burns.

CONTRA: NO PREGNANCY or CHILDREN--deposits on bone and discolors permanent teeth (chelator of minerals).

Term
Clindamycin
Definition

Lincosamide.

MECH: Binds to 50S ribosomal subunit supressing protein synthesis.

USE: Staph. aureas (85% vs. MRSA; 100% vs. MSSA). Streptococci. Anaerobes (EXCEPT C. Diff). NO GRAM (-) action. Good in bowel perforations (anaerobic infections), aspiration pneumonia, Gram (+) infections where patient is allergic to penicillin.

TOX: Antibiotic related diarrhea and C. Diff pseudomembranous colitis.

Term

Erythromycin

Clarithromycin

Azithromycin

Definition

Macrolides.

MECH: Binds to 50S ribosomal subunit inhibiting protein synthesis.

USE: Streptococci, Staph. aureas (85% MRSA), mycoplasma, (also Haemophilus and chlamydia--esp. azithromycin). Alternative for gram (+) coverage in penicillin allergic patients. Azithromycin also has wide tissue distribution and long half life.

TOX: GI distress, n + v. Metabolized in liver. Erythromycin and clarithromycin block certain Cytochromes increasing cyclosporin conc. etc...

Term
Linezolid
Definition

Oxazolidinones.

MECH: Inhibition of 50S ribosomal subunit at peptidyl transferase site. Used (along with Daptomycin) against VRSA and Vanco resistant enterococcus.

USE: Marketed for MRSA but as effective as cheaper generics.

TOX: Bone marrow suppression with >2wk use.

Term
Trimethoprim/Sulfamethoxazole (Bactrim)
Definition

Sulfonamide drugs (PABA analogs).

MECH: Inhibition of dihydropteroate synthase preventing the incorporation of dihydropteroic acid into PABA in order for microbes to synthesize Folic Acid. Bacteriostatic.

Trimethoprim = Dihydrofolate reductase inhibitor.

USE: For uncomplicated UTIs. Otitis media in children infected with sensitive Haemophilus or S. pneumonia.

 

Term
Pyrimethamine/dapsone
Definition
Pyrimethamine is a DHFR inhibitor used with dapsone as an alternative to TMP/SMX for parasitic infections.
Term
TB therapy guidelines.
Definition

Use 4 drugs for two months until sensitivities are discovered, then drop 2 drugs.

6 month treatment for initial, 18 months for recurrent.

 

Term
Isoniazid (INH)
Definition

For TB treatment. Prodrug.

MECH: Prodrug activated within bacillus by KatG leading to inhibition of mycolic acid synthesis and cell death.

TOX: Centrolobular hepatitis (jaundice with elevated aminotransferases); neurotoxicity (pyridoxine prevents).

Term
Rifampin
Definition

Rifamycin.

MECH: Binds RNA polymerase preventing RNA synthesis.

USE: With Isoniazid for TB therapy.

TOX: Centrolobular hepatitis (high aminotransferases and jaundice); serious flu-like hypersensitivity reactions--especially if used intermittently).

Term
Pyrazinamide
Definition

Nicotinamide analog.

MECH: Activated by acidic environment (inside macrophage phagosomes or edges of necrotic granulomas where lactic acid is high); deaminated by mycobacterium nicotinamidase to pyrazinoic acid which is pumped out of the cell where it picks up a proton and diffuses back into cell then targets Fatty Acid Synthase I in mycolic acid synthesis.

USE: For TB therapy.

TOX: Centrolobular hepatitis; increased uric acid levels--->gout.

Term
Ethambutol
Definition

MECH: Inhibition of arabinosyl transferase involved in cell wall synthesis.

USE: TB infections--most active during growth phase so dropped (along with pyrazinamide) after 2 months.

TOX: Dose-dependent optic neuritis (inability to differentiate red and green); elevated uric acid---> gout.

Term

Gatifloxacin

Temofloxacin

Definition

Fluoroquinolones.

USE: Active against resistant MTb for up to 24 months in comotherapy.

TOX: Well-tolerated. Resistance can occur.

Term

Kanamycin

Streptomycin

Amikacin

Definition

Aminoglycosides.

USE: For resistant MTb.

TOX: Kanamycin: VERY TOXIC -- neuromuscular blockade, agranulocytosis. Streptomycin: ototoxic>>nephrotoxic. Amikacin: balanced ototoxicity=nephrotoxicity.

NEVER USE AMINOGLYCOSIDES IN COMBINATION!

Term
Ethionamide
Definition

MECH: Prodrug activated within bacillus by KatG leading to inhibition of enoyl-ACP reductase of fatty synthase II leading to inhibition of mycolic acid synthesis and cell death.

USE: Resistant MTb.

TOX: Neurotoxicity similar to INH---> B6 may help ameliorate.

Term
Cycloserine
Definition

MECH: Broad spectrum cell-wall synthesis inhibitor where alanine is used.

USE: Resistant MTb.

TOX: Severe CNS toxicity within 2 weeks--may disappear with discontinued use.

Term
Aminosalicylic Acid
Definition

MECH: Specific inh. of MTb dihydropteroate sythase (sulfonamides can't act on MTb).

USE: Resistant MTb.

TOX: GI probs, Allergic phenomena, blood dyscrasias.

Term
Capreomycin
Definition

MECH: Unclear. Cross-resistance with aminoglycosides.

USE: Resistant MTb.

TOX: Significant--tinnitus, hearing loss, renal faliure, blood dyscrasia.

 

Term

Acyclovir

Valacyclovir

Famcyclovir

Definition

Purine analogs. Valacyclovir is a prodrug of acyclovir.

MECH: DNA synth. inhibitors.

USE: HSV, VZV.

TOX: LOW. VZV requires higher dosage. CNS effects can occur if not renally dosed in presence of renal disease.

 

 

Term
Sorivudine
Definition

MECH: Pyramidine analog inhibitor of DNA synth.

USE: More active against VZV. Variable effects against HSV.

 

Term
Foscarnet
Definition

MECH: Non-nucleoside analogue, pyrophosphate congener. IV only due to high ionization--renal excr.

USE: Broad-spectrum: Broad spectrum. DNA viruses (HSV, VZV, CMV) and RNA viruses including HIV. Used in acyclovir failures.

TOX: Dose-dep. renal and CNS toxicity.

 

Term
Ganciclovir
Definition

MECH: Guanine analogue

USE: CMV infections in immunocompromised (transplant and HIV--retinitis tmt. or prophylaxis).

TOX: Neutropenia, thrombocytopenia--dose dependent. Also, CNS effects.

 

Term
Imiquimod
Definition

MECH: Immunomodulator enhances interferon production.

USE: Topical treatment for HPV.

Term
Cidofovir
Definition

MECH: Cytosine analogue inhibits DNA production.

USE: HPV and other DNA viruses. There is a topical available.

Term

Oseltamivir (Tamiflu)

Zanumavir

Peramivir

Definition

Oseltimavir is oral; zanumavir is inhalational; peramivir is IV. Use against RNA viruses.

MECH: Neuramidinase inhibition prevents release of viruses from host cells. Neuramidinase is on influenza A and B.

USE: Treatment of influenza A, B and H1N1. Prophylaxis in high risk populations. Treatment within 1-2 days reduces length of symptoms and decreases viral shedding (decr. transmission).

TOX: Neuropsychiatric toxicity.

Term

Nevirapine (NVP)

Delavirdine (DLV)

Efavirenz (EFV)

Etravirine

Definition

Non-nucleoside Reverse Transcriptase Inhibitors

MECH: Binds allosterically to Reverse Transcriptase, inhibiting DNA synthesis.

USE: HIV-1 only. (if intolerant to protease inhibitors, these may take place).

TOX: Skin rashes. Affect Cytochrome P450 metabolism. Resistance is a concern.

Term

Zidovudine (AZT)

Didanosine (DDI)

Stavudine (D4T)

Lamivudine (3TC)

Definition

Nucleoside Reverse Transcriptase inhibitors. Components of HAART therapy.

TOX: Zidovudine--granulocytopenia, n + v, anemia. Didanosine--Pancreatitis, peripheral neuritis. Stavudine--Periph. neuropathy, pancreatitis. Lamivudine--headache, n+v, rash, neutropenia, pancreatitis.

Term
Saquinavir
Definition

MECH: Protease inhibitors. HIV protease cleaves polyprotein into active components of HIV virion. Without it, the HIV virus is non-virulent.

USE: HIV--very active.

TOX: Poor oral bioavailability but well-tolerated. Lipodystrophy--atrophy of subcutaneous fat. Also hyperglycemia, hyperlipidemia and Cushing's-like fat redistribution.

Term
Ritonavir
Definition

MECH: Protease inhibitors. HIV protease cleaves polyprotein into active components of HIV virion. Without it, the HIV virus is non-virulent.

USE: HIV

TOX: More toxic than saquinavir--peripheral neuropathy, liver enzyme elevation. ALSO, potent cytochrome inhibitor boosts other protease inhibitors. Lipodystrophy--atrophy of subcutaneous fat. Also hyperglycemia, hyperlipidemia and Cushing's-like fat redistribution.

Term
Indinavir
Definition

MECH: Protease inhibitors. HIV protease cleaves polyprotein into active components of HIV virion. Without it, the HIV virus is non-virulent.

USE: HIV.

TOX: Slow development of resistance but once this occurs, the strain is resistant to both saquinavir and ritonavir. Nephrolithiasis--hydrate patients! Lipodystrophy--atrophy of subcutaneous fat. Also hyperglycemia, hyperlipidemia and Cushing's-like fat redistribution.

 

Term
Enfuvirtide
Definition

MECH: incorporates into HIV gp41 causing a conformational change inhibiting the virus' ability to bind to the CD4+ T-cells.

USE: HIV-resistant strains only.

 

Term
Meraviroc
Definition

MECH: Binds T-cell CCR5 co-receptor prevents HIV gp120 binding and entry into lymphocyte.

TOX: Involves CD4+ membrane CCR5 receptor so may inhibit immunologic attack on microbes that are controlled by cell-mediated immunity (TB, fungi).

Term
What drugs do you treat HepC with? (4)
Definition

Interferon and Ribavirin (Purine nucleoside analog. Broad spectrum) together but non-selective.

Add Boceprevir or Teleprevir - these are HCV-specific protease inhibitors that act directly. Triple therapy.

Term
Amphoteracin B
Definition

USE: Life-threatening systemic mycoses. Occasionally used in combo (w/ flucytosine) for immunocompromised hosts with severe fungal infections.

TOX: Acute fever, chills, hypotension potential. Renal impairment almost always--and may be only partially reversable; Mg and K wasting; renal tubular acidosis. Normocytic anemia.

Term
Nystatin
Definition
USE: Topical only for candidiasis.
Term
Miconazole
Definition

An imidazole.

USE: Topical for candidiasis and dermatophytes. Troche (losenge-like) dosage effective in thrush.

Term
Clotrimazole
Definition

An imidazole.

USE: Topical for candidiasis and dermatophytes. Troche (losenge-like) dosage effective in thrush.

Term
Fluconazole
Definition

Triazole.

USE: Dermatophytes. Deep and superficial fungal infections. Oral administration when imidazoles fail.

TOX: Rarely hepatotoxicity. Inhibits Cytochromes.

Term
Itraconazole
Definition

Triazole.

USE: Dermatophytes. Onchymycosis. Oral administration when imidazoles fail.

TOX: Rarely hepatotoxicity. Inhibits Cytochromes.

Term
Voriconazole
Definition

Triazole.

USE: Dermatophytes. Oral administration when imidazoles fail.

TOX: Rarely hepatotoxicity. Inhibits Cytochromes.

Term
Terbinafine
Definition

Allylamine

USE: Topical dermatophytes that are refractory to imidazoles -- not so much candida. Also oral formulation for onchymycoses.

TOX: Hepatitis, rarely.

 

Term
Naftifine
Definition

Allylamine

USE: Topical dermatophytes that are refractory to imidazoles -- not so much candida.

TOX: Hepatitis, rarely.

Term
Tolnaftate
Definition

Allylamine

USE: Topical dermatophytes that are refractory to imidazoles -- not so much candida. Weak agent.

TOX: Hepatitis, rarely.

Term
Caspofungin
Definition

Echinocandin.

MECH: Inhibition of fungal wall synthesis--inhibits glucan synthase complex.

USE: Life-threatening fungal infections unresponsive to older agents--especially candida and aspergillus.

TOX: Less than amphoteracin B.

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