microbio antimicrobials Flashcards
penicllin G (IV and IM) and penicillin V (oral)
bind penicillin binding proteins (transpeptidases) and block transpeptidase crosslinking of proteoglycans in the cell wall; used for gram pos (strep, actinomyces); also used for gram neg cocci (mainly meningococcus) and spirochetes (t. pallidum); bactericidal; can see hypersens reactions and hemolytic anemia
amoxicillin, ampicillin
same mechanism as penicillins but wider spectrum, but still penicillinase sens; can be used for H. influenzae, H. pylori, E coli, Liseria, proteus, salmonella, shigella, enterococci
dicloxacillin, nafcillin, oxacillin
these are the penicillinase-reistant penicillins; used for staph aureus (but not MRSA); can cause hypersens reactions or interstitial nephritis
piperacillin, ticarcillin
antipseudomonal penicilllins; used for pseudomonas and gram neg rods; susceptible to penicillinase; use with beta-lactamase inhib
beta-lactamase inhibitors
clavulanic acid, sulbactam, tazobactam; often added to the penicillin antibiotics
first generation cephalosporins
cephalexin, cefazolin; gram pos cocci, proteus, e coli, klebsiella; cefazolin is often used prior to surgery to prevent staph aureus wound infections
second generation cephalasporins
cefoxitin, cefaclor, cefuroxime; gram pos cocci, h flu, enterobacter, neisseria, proteus, e. coli, klebsiella, serratia
third gen cephalasporins
ceftriaxone, cefotaxime, ceftazidime; serious gram neg infections
fourth gen cephalasporins
cefepime; gram neg organisms, with increaed activity against pseudomonas and gram pos organisms
fifith gen cephalasporins
ceftaroline; broad gram pos and gram neg organism coverage, incl MRSA; does not cover pseudomonas
ceftazidime
good pseudomonas coverage
toxicity of the cephalasporins
hypersens reactions, autoimmune hemolytic anemia, disulfuram-like reaction, vit K def, exhibit cross-reactivity with penicillins; they increase the nephrotoxicity of aminoglycosides
carbapenems
imipenem, meropenem, ertapenem, doripenem; these inhibit cell wall synthese and are resistant to beta lactamase; used for gram pos cocci, GNR, and anaerobes; wide spectrum but signif side effects; toxicity includes GI distress, skin rash, and CNS toxicity (seizures) at high levels
imipenem
always administered with cilastatin to decreae inactivation of the drug in renal tubules
monobactams
aztreonam; inhibits cell wall synthesis; no cross-allergenicity with penicillins; used for gram neg rods only (no activity against gram pos or anaerobes); used in penicillin-allergic patients and those with renal insuff who cannot tolerate aminoglycosides; usually nontoxic, occasional GI upset
vancomycin
inhibits cell wall peptidoglycan formation by binding D-ala D-ala portion of cell wall precursors; not sucesceptible to beta lactamases; used for gram pos only (MRSA< staph epi, enterococcus, c. diff); nephrotoxicity, ototoxicity, thrombophlebitis, red man syndrome (diffuse flushing, but can be prevented with antihistamines and slow infusion rate); resistance develops when bacteria change D-ala D-ala to D-ala D-lac
aminoglycosides
gentamycin, neomycin, amikacin, tobramycin, and streptomycin; inhibit 30S subunit; use for severe gram neg rod infections; synergystic with beta lactams; toxicity is nephrotoxicity, neuromuscular blockade, ototoxicity (esp when used with loop diuretics), teratogen;
tetracylcines
tetracycline, doxy, minocycline; 30S inhibitor; limited CNS penetration; doxy is fecally eliminated and can be used in patients with renal failure; do not take teracyclines with milk, antacids, or iron-containing preparations bc divalent cations inhibit drug’s absorption in the gut; great intracellular accumulation, so good against rickettsia and chlamydia; also used to tx acne
toxicity of tetracyclines
GI distress, discoloration of teeth and inhib of bone growth in kids, photosens; contraindic in pregnancy
chloramphenicol
blocks peptidyltransferase at 50S ribisomal subunit; toxicity is anemia (dose-dep), apalstic anemia (dose-indep), gray baby syndrome (in premature infants)
clindamycin
block peptide transfer at 50S; used for anerobes in aspiration pneumonia, lung abscesses, and oral infections; also effective against invasive group A strep; “treats anaerobes above the diaphragm vs. metronidazole, which treats them below the diaphragm”; assoc with pseudomembranous collitis, fever, diarrhea
linezolid
inhibits protein synthesis at the 50S subunit; good for gram pos species, incl MRSA and VRE; can cause bone marrow suppression (esp thrombocytopenia), peripheral neuropathy, serotonin syndrome
macrolides
azithromycin, clarithromycin, erythromycin; inhibit 50S; use for atypical pneumonias (legionell, mycoplasma, chalamydia), STIs (chlamydia), gram pos cocci (strep), and b. pertussis; toxicity includes GI, arrythmia caused by prolong QT, acute cholestatic hepatitis, rash, eosinophilia; increases serum concentrations of theophyllines and oral anticoagulants; Clarithromycin adn erythromycin inhib P450
trimethoprim
inhibits bacterial dihydrofolate reductase; used in combo with sulfonamides, causing sequential block of folate synthesis; toxicity is megaloblastic anemia, leukopenia, granulocytopenia (may allev with suplemental folinic acid)
sulfonamides
inhibit folate synthesis; PABA antimetabolites inhibit dihydropteroate synthase (Dapson, used to treat lepromatous leprosy, is a closely related drug that also inhibits folate synthesis); treats GP, GN, nocardia, chlamydia; toxicity is hypersens reactions, hemolysis if G6PD def, nephrotoxicity (TIN), photosensitivity, kernicterus in infants, displace other drugs from albumin;
prophylaxis for TB
isoniazid
treatment for TB
rifampin, isoniazid, pyrazinamide, ethambutol (RIPE); isoniazid and ethambutol act on the cell wall, while rifampin inhibits mRNA synthesis, and pyrazinimide has unknown mechanism
rifamycins
rifampin, rifabutin; inhibit DNA-dep RNA polymerase; used for TB, also to delay resistance to dapsone when used for leprosy, used for meningococcal proph and chemoproph in contacts of kids with HIB; toxicity is minor hepatotoxicity and drug interactions (increases cyp450), organge body fluids; monotherapy rapidly leads to resistance
isoniazid
decreases synthesis of mycolic acids; treats TB; this is the only agent used as solo prophylaxis against TB; toxicity includes neurotoxicity, hepatotoxicity, pyridoxine (Vit B6) can prevent neurotoxicity; INH Injures Neurons and Hepatocytes
Pyrazinamide
mech unknown; used to treat TB; toxicity is hyperuricemia and hepatotoxicity
Ethambutol
decreases carbohydrate polymerization of mycobacterium cell wall; toxicity is optic neuropathy
fluoroquinolones
inhibit prokaryotic enzymes topoisomerase II and topoisomerase IV; must not be taken with antacids; used for GNR of urinary and GI tracts (incl pseudomonas), neisseria, some GP organisms; toxicity is GI upset, skin rashes, HA, dizziness; less commonly cau cause leg cramps and myalgias; contraindicated in pregnant women and nursing women; may prolong QT; may cause tendonitis or tendon rupture
daptomycin
disrupts cell membrane of GPC; great for staph aureus skin infections (esp MRSA), bacteremia,, endocarditis, VRE; NOT used for PNA (inactivated by surfactant); toxicity is myopathy and rhabdo
metronidazole
forms toxic free radical metabolites in the bacterial cell that damage DNA; treats giardia, entamoeba, trichomonas, gardnerella vaginalis, anaerobes (incl b. frag and c. diff); used with PPI and clarithromycin in triple therapy against H pylori; toxicity is disulfuram-like reaction (severe flushing, tachycardia, hypotension) with alcohol; headache, metallic taste
Prophylaxis for patients at high risk for endocarditis and undergoing surgical or dental procedure
amoxicillin
prophylaxis for exposure to gonorrhea
ceftriaxone
prophylaxis for history of recurrent UTIs
bactrim
proph for exposure to meningococcal infection
ceftriaxone, cipro, or rifampin
proph for pregnant women carrying GBS
penicillin G
proph for prevention of gonococcal conjunctivitis in the newborn
erythromycin ointment
proph for prevention of post surgical infection due to staph aureus
cefazolin
proph for strep pharyngitis in child with prior rheumatic fever
benzathine penicillin G or oral penicillin V
proph for exposure to syphillis
penicillin G
proph for CD4 less than 200
bactrim for PCP proph
proph for CD4 less than 100
bactrium for PCP and toxo
proph for CD4 less than 50
azithro or clarithro for MAC
What drugs cover MRSA?
Vanc, dapto, doxy, bactrim, linezolid, tigecycline, ceftaroline
What drugs cover VRE?
linezolid and strepogramins
amphotericin B
antifungal that binds ergosterol and forms pores that allow leakage of electrolytes out of the fungal membrane; ; toxicity includes fevers, chills, hypotension, nephrotoxicity, arrhythmias, anemia, IV phlebitis
nystatin
same mech as amphotericin B; topical use only as too toxic for systemic use; swish and swallow for oral candidiasis; topical for diaper rash or vaginal candidiasis
flucytosine
inhibits DNA and RNA biosynthesis; toxicity is bone marrow suppression
azoles
inhibit fungal sterol (ergosterol) synthesis by inhibiting the cyp450 enzyme that converts lanosterol to ergosterol; used for local and less serious systemic mycoses; toxicity is that it has testosterone synthesis inhib, esp with ketoconazole, liver dysfunction
terbinafine
inhibits the fungal enzyme squalene epixidae; used to treat dermaophytes (esp toenail infxn); can cause GI upset, HA, hepatotoxicity, taste disturbance
echinocandins
examples are caspofungin, micafungin, and anidulafungin; inhibit cell wall synthesis; causes GI upset and flushing due to histamine release
griseofulvin
interferes with microtubule function and disrupts mitosis; deposits in keratin containing tissues, like nails; oral tx of superficial infections; caution because it is a teratogen, carcinogenic, can cause confusion, HA, increase cyp450 and warfarin metabolism
antiprotozoan therapy
pyrimethamine (toxo);suramin and melarsprol (trypansoma brucei), nifurtimox (t. cruzi), sodium stibogluconate (leishmaniasis)
anti-mite/louse therapy
permethrin (neurotoxicity); malathion (achesterase inhib); lindane (neurotox); used to treat scabies and lice
chloroquine
blocks detoxification of heme into hemozoin; heme accumulates and is toxic to plasmodia; used for treatment of plasmodial species other than p. falciparum (high resistance in p. falciparum); toxicity is retinopathy, pruritis
antihelminthic therapy
mebendazole, pyrantel pamoate, ivermectin, diethylcarbamazine, praziquantel
oseltamavir, zanamivir
inhibits influenza neuraminidase (decreased release of progeny of virus); treatment and prevention of both flu A and B
acyclovir, famcyclovir, valacyclovir
guanosine analogue; preferentially inhibits viral DNA polymerase by chain termination; used for HSV and VZV, weak activity against EBV, no activity against CMV; toxicity includes obstructive crystalline nephropathy and acute renal failure if not adequately hydrated
ganciclovir
preferentially inhibits viral DNA polymerase; used for CMV; toxicity include leukopenia, neutropenia, thrombocytopenia, and renal toxicity
foscarnet
viral DNA/RNA polymerase inhib and HIV reverse transcriptase inhib; used for CMV retinitis in immunocompromised patients when gancyclovir fails and used for acyclovir resistant HSV; nephrotoxic, electrolyte abnormalities can lead to seizures;
cidofovir
inhibits viral DNA polymerase; used for CMV retinitis in immunocompromised patients and in those with acyclovir resistant HSV; has long half life; toxicity is nephrotoxicity (coadminister with probenecid and IV saline to decrease toxicity)
HIV therapy
2 NRTIs and 1 of the following: NNRTI or protease inhib or integrase inhib
protease inhib
“-navir”; “navir tease a protease”; can cause hyperglycemia, GI intolerance, lipodystrophy, nephropathy, hematuria (indinavir); rifampin is contraindicated with protease inhib because it can decreaed protease inhib concentration
ritonavir
can boost other drugs by inhibiting cytochrome p-450
NRTIs
abacavir, didanosine, emtricitabine, lamivudine, stavudine, tenofovir, zidovudine (formerly AZT); toxicities are bone marrow suppression which can be reversed with G-CSF and EPO, peripheral neuropathy, lactic acidosis (nucleosides), anemia (ZDV), and pancreatitis (didanosine)
NNRTIs
delavirdine, efavirenz, nevirapine; toxicities include rash and hepatotoxicity are common to all, vivid dreams and CNS sx are common with efavirenz. Delavirdine and efavirenz are contraindic in pregnancy
integrase inhib
raltegravir; increases CK
fusion inhib
enfuvirtide, maraviroc; these can cause skin reaction at injection site
interferon alpha
treats chronic hep b and c, kaposi sarcoma, hairy cell leukemia, condyloma acuminatum, RCC and melanoma
interferon beta
treats multiple sclerosis
inteferon gamma
treats chronic granulomatous disease
toxicity of interferons
neutropenia and myopathy
Hep C therapy
ribavirin, simeprevir, and sofosbuvir
ribavirin
used for chronic hep c, also used in RSV; toxicity is hemolytic anemia and severe teratogen
simeprevir
hep C protease inhib; prevents viral replication; used for chronic hep c in combo with ribavirin and pedinterferon alfa; do not use as monotherapy; can cause photosensitivity reactions, rash
sofosbuvir
inhibits hep C RNA polymerase acting as chain terminator; used for chronic hep C in combo with ribavirin with or without peginterferon alfa; do not use as monotherapy; toxicity is headache, fatigue, nausea
hydrogen peroxide
free radical oxidation. Sporocidal
iodine and iodophors
halogenation of DNA, RNA, and proteins. May be sporocidal
antibiotics to avoid in pregnancy
sulfonamides (kernicterus), aminoglycosides (ototoxicity), fluoroquinolones (cartilage damage), clarithromycin (embryotoxic), tetracyclines (discolored teeth, inhib of bone growth), ribavirin (teratogenic), griseofulvin (teratogenic), chloramphenicol (gray baby syndrome)
