Anti-Microbials Part 2 Flashcards
what is the prophylaxis if patient is at high risk for endocarditis and undergoing surgical or dental procedures?
- amoxicillin
what is the prophylaxis for exposure to gonorrhea?
- ceftriaxone
what is the prophylaxis for history of recurrent UTIs?
- TMP-SMX
what is the prophylaxis to exposure to meningococcal infections?
- ceftriaxone
- ciprofloxacin
- rifampin
what is the prophylaxis for a pregnant woman carrying gruop B strep?
- intrapartum penicillin G
- ampicillin
what is the prophylaxis for prevention of gonococcal conjunctivitis in newborns?
- erythromycin ointment on eyes
what is the prophylaxis for prevention of postsurgical infection due to S. aureus?
- Cefazolin
what is the prophylaxis for strep pharyngitis in child with prior rheumatic fever?
- benzathine penicillin G
- oral penicillin V
what is the prophylaxis for exposure to syphilis?
- benzathine penicillin G
HIV infection for cell count of CD4 < 200 cells/mm3
Pneumocystis pneumonia
prophylaxis for HIV patients with cell count CD4 < 200 cells/mm3
TMP-SMX
HIV infection for cell count of CD4 < 100 cells/mm3
Pneumocystis pneumonia and toxoplasmosis
prophylaxis for HIV patients with cell count CD4 < 100 cells/mm3
TMP-SMX
HIV infection for cell count of CD4 < 50 cells/mm3
Mycobacterium avium complex
prophylaxis for HIV patients with cell count CD4 < 50 cells/mm3
azithromycin or clarithromycin
what are the treatments for MRSA?
- vancomycin
- daptomycin
- linezolid
- tigecycline
- ceftaroline
what are the treatments for VRE?
- linezolid and streptogramins (quinupristin, dalfopristin)
what are the treatments for multidrug resistant P. aeruginosa, multidrug resistant Acinebacter baumannii?
- polymyxins B and E (colistin)
antifungal drugs that disrupt cell membrane integrity
- amphotericin B
- nystatin
antifungal drugs that inhibit nucleic acid synthesis
- flucytosine
antifungal drugs that inhibit cell wall synthesis
- echinocandins
- anidulafungin
- caspofungin
- micafungin
antifungal drugs that inhibit lanosterol synthesis
- terbinafine
antifungal drugs that inhibit ergosterol synthesis
- azoles
- clotrimazole
- fluconazole
- itraconazole
- ketoconazole
- miconazole
- voriconazole
amphotericin B–mechanism
- binds ergosterol (unique to fungi)
- forms membrane pores that allow leakage of electrolytes
- “amphotericin “tears” holes in the fungal membrane by forming pores”
amphotericin B–use
- serious, systemic mycoses
-
Cryptococcus
- amphotericin B with or without flucytosine for cryptococcal meningitis
- Blastomyces
- Coccidioides
- Histoplasma
- Candida
- Mucor
- intrathecally for fungal meningitis
what should you supplement amphotericin B use with and why?
- K+ and Mg+ b/c of altered renal tubule permeability
amphotericin B–toxicity
- fever/chills–“shake and bake”
- hypotension
- nephrotoxicity
- arrhythmias
- anemia
- IV phlebitis–“amphloterrible”
what decreases the risk of nephrotoxicity from taking amphotericin B?
- hydration
what decreases toxicity from taking amphotericin B?
- liposomal amphotericin
nystatin–mechanism
- same as amphotericin B
- binds ergosterol (unique to fungi)
- forms membrane pores that allow leakage of electrolytes
- topical use only as too toxic for systemic use
nystatin–use
- “swish and swallow” for oral candidiasis (thrush)
- topical for diaper rash or vaginal candidiasis
flucytosine–mechanism
- inhibits DNA and RNA biosynthesis by conversion to 5-fluorouracil by cytosine deaminase
flucytosine–use
- systemic fungal infections (especially meningitis caused by Cryptococcus) in combination with amphotericin B
flucytosine–toxicity
- bone marrow suppression
name the azoles
- clotrimazole
- fluconazole
- itraconazole
- ketoconazole
- miconazole
- voriconazole
azoles–mechanism
- inhibit fungal sterol (ergosterol) synthesis by inhibiting the cytochrome P-450 enzyme that converts lanosterol to ergosterol
azoles–use
- local and less serious systemic mycoses
fluconazole–use
- (azole)
- chronic suppression of cryptococcal meningitis in AIDS patients and candidal infections of all types
itraconazole–use
- (azole)
- Blastomyces
- Coccidioides
- Histoplasma
clotrimazole and miconazole–use
- (azole)
- for topical fungal infections
azoles–toxicity
- testosterone synthesis inhibition
- gynecomastia, especially with ketoconazole
- liver dysfunction
- inhibits cytochrome P-450
terbinafine–mechanism
- inhibits the fungal enzyme squalene epoxidase
terbinafine–use
- dermatophytoses
- especially onychomycosis–fungal infection of finger or toe nails
terbinafine–toxicity
- GI upset
- headaches
- hepatotoxicity
- taste disturbance
name the echinocandins
- anidulafungin
- caspofungin
- micafungin
echinocandins–mechanism
- inhibit cell wall synthesis by inhibiting synthesis of beta glucan
echinocandins–use
- invasive aspergillosis
- Candida
echinocandins–toxicity
- GI upset
- flushing (by histamine release)
griseofulvin–mechanism
- interferes with microtubule function
- disrupts mitosis
- deposits in keratin containing tissues
- ie. nails
griseofulvin–use
- oral treatment of superficial infections
- inhibits growth of dermatophytes (tinea, ringworm)
griseofulvin–toxicity
- teratogenic
- carcinogenic
- confusion
- headaches
- inc cytochrome P-450
- inc warfarin metabolism
antiprotozoan therapy
- pyrimethamine–toxoplasmosis
- suramin and melarsoprol–Trypanosoma brucei
- nifurtimox–T. cruzi
- sodium stibogluconate–leishmaniasis
anti mite/louse therapy
- permethrin
- malathion
- lindane
- used to treat scabies (Sarcoptes scabei) and lice (Pediculus and Pthirus)
- “treat PML (Pesty Mites and Lice) with PML (Permethrin, Malathion, Lindane), b/c they NAG you (Na, AChE, GABA blockade)”
permethrin–mechanism
- (anti-mite/louse therapy)
- blocks Na+ channels –> neurotoxicity
- “treat PML (Pesty Mites and Lice) with PML (Permethrin, Malathion, Lindane), b/c they NAG you (Na, AChE, GABA blockade)”
malathion–mechanism
- (anti mite/louse therapy)
- acetylcholinesterase inhibitor
- “treat PML (Pesty Mites and Lice) with PML (Permethrin, Malathion, Lindane), b/c they NAG you (Na, AChE, GABA blockade)”
lindane–mechanism
- (anti mite/louse therapy)
- blocks GABA channels –> neurotoxicity
- “treat PML (Pesty Mites and Lice) with PML (Permethrin, Malathion, Lindane), b/c they NAG you (Na, AChE, GABA blockade)”
chloroquine–mechanism
- blocks detoxification of heme into hemozoin
- heme accumulates and is toxic to plasmodia
chloroquine–use
- treatment of plasmodial species other than P. falciparum
- frequency of resistance in P falciparum is too high
why does P. falciparum have high resistance to chloroquine and how should you treat it?
- resistance due to membrane pump that dec intracellular concentration of drug
- treat with artemether/lumefantrine or atovaquone/proguanil
how should you treat malaria?
- quinidine in US (quinine elsewhere)
- artesunate
chloroquine–toxicity
- retinopathy
- pruritis–especially in dark skinned individuals
antihelminthic therapy
- Mebendazole–microtubule inhibitor
- pyrantel pamoate
- ivermectin
- diethylcarbamazine
- praziquantel
oseltamivir, zanamivir–mechanism
- inhibit influenze neuroaminidase –> dec release of progeny virus
oseltamivir, zanamivir–use
- treatment and prevention of both influenza A and B
acyclovir, famciclovir, valacyclovir–mechanism
- guanosine analogs
- monophosphorylated by HSV/VZV thymidine kinase and not phosphorylated in uninfected cells –> few adverse effects
- triphosphate formed by cellular enzymes
- preferentially inhibit viral DNA Polymerase by chain termination
acyclovir, famciclovir, valacyclovir–use
- HSZ and VZV
- weak activity against EBV
- no activity against CMV
- used for HSV-induced mucocutaneous and genital lesions as well as for encephalitis
- prophylaxis in immunocompromised patients
- no effect on latent forms of HSV and VZV
valacyclovir vs. acyclovir
- valacyclovir is a prodrug of acyclovir
- valacyclovir has better oral availability
acyclovir, famciclovir, valacyclovir–toxicity
- obstructive crystalline nephropathy
- acute renal failure
- both may occur if not adequately hydrated
acyclovir, famciclovir, valacyclovir–mechanism of resistance
- mutated viral thymidine kinase
ganciclovir–mechanism
- 5’ monophosphate formed by a CMV viral kinase
- guanosine analog
- triphosphate formed by cellular kinases
- preferentially inhibits viral DNA polymerase
ganciclovir–use
- CMV–especially in immunocompromised patients
vanganciclovir vs. ganciclovir
- vanganciclovir is a prodrug of ganciclovir
- vanganciclovir has better oral availability
ganciclovir–toxicity
- bone marrow suppression–leukopenia, neutropenia, thrombocytopenia
- renal toxicity
- more toxic to host enzymes than acyclovir
ganciclovir–mechanism of resistance
- mutated viral kinase
foscarnet–mechanism
- viral DNA/RNA polymerase inhibitor
- HIV reverse transcriptase inhibitor
- binds to pyrophosphate binding site of enzyme
- does not require any kinase activity
- “foscarnet = pyrofosphate analog”
foscarnet–use
- CMV retinitis in immunosompromised patients when ganciclovir fails
- acyclovir resistant HSV
foscarnet–toxicity
- nephrotoxicity
- electrolyte abnormalities can lead to seizures
- hypo/hypercalcemia
- hypo/hyperphosphatemia
- hypokalemia
- hypomagnesemia
foscarnet–mechanism of resistance
- mutated DNA polymerase
cidofovir–mechanism
- preferentially inhibits viral DNA polymerase
- does not require phosphorylation by virla kinase
cidofovir–use
- CMV retinitis in immunocompromised patients
- acyclovir resistant HSV
- long half life
cidofovir–toxicity
- nephrotoxicity
how to decrease possible toxicity of cidofovir?
- coadminister with probenecid and IV saline
HIV therapy
- highly active antiretroviral therapy (HAART)
- often initiated at the time of HIV diagnosis
what does the highly active antiretroviral therapy for HIV consist of?
- 3 drugs to prevent resistance
- 2 NRTIS
- 2 integrase inhibitor
what are the strongest indications for patients to receive HAART?
- AIDS defining illness
- low CD4+ cell counts (<500 cells/mm3)
- high viral load
what are the 5 classes of HIV therapy drugs?
- NRTIs
- NNRTIs
- protease inhibitors
- integrase inhibitors
- fusion inhibitors
name the NRTIs
- Abacavir (ABC)
- DIdanosine (ddl)
- Emtricitabine (FTC)
- Lamivudine (3TC)
- Stavudine (d4T)
- Tenofovir (TDF)
- Zidovudine (ZDV, formerly AZT)
NRTIs–mechanism
- competitively inhibit nucleotide binding to reverse transcriptase and terminate the DNA chain (lack a 3’ OH group)
which of the NRTIs are nucleotides? which are nucleosides?
- Tenofovir is a nucleoTide
- the others are nucleosides and nee to be phosphorylated to be active
- “Have you dined (vudine) with my nuclear (nucleosides) family?”
what is special about Zidovudine (ZDV)?
- can be used as a general prophylaxis
- can be used during pregnancy to dec risk of fetal transmission
when is Abacavir (ABC) contraindicated?
- when the patient has an HLA-B*5701 mutation
NRTIs–toxicity
- bone marrow suppression–can be reversed with granulocyte colony stimulating factor (G-CSF) and erythropoietin
- peripheral neuropathy
- lactic acidosis–nucleosides
- anemia–ZDV
- pancreatitis–didanosine
name the 3 NNRTIS
- delavirdine
- efavirenz
- nevirapine
NNRTIs–mechanism
- bind to reverse transcriptase at site different from NRTIs
- do not require phosphorylation to be active or compete with nucleotides
what are common toxicity signs for all NNRTIs?
- rash
- hepatotoxicity
efavirenz–toxicity
- (NNRTI)
- vivid dreams
- CNS symptoms
what is a contraindication for delavirdine and efavirenz?
- (NNRTI)
- pregnancy
name the protease inhibitors
- atazanavir
- darunavir
- fosamprenavir
- indinavir
- lopinavir
- ritonavir
- saquinavir
- “Navir (never) tease a protease”
protease inhibitors–mechanism
- assembly of virions depends on HIV-1 protease (pol gene) which cleaves the polypeptide products of HIV mRNA into their functional parts
- so, pretease inhibitors prevent maturation of new viruses
what is important about ritonavir?
- (protease inhibitor)
- can “boost” other drug concentrations by inhibiting cytochrome P-450
protease inhibitors–toxicity
- hyperglycemia
- GI intolerance–nausea, diarrhea
- lipodystrophy–Cushing like syndrome
indinavir–toxicity
- (protease inhibitor)
- nephropathy
- hematuria
why is rifampin contraindicated with protease inhibitors?
- rifampin is a potent CYP/UGT inducer
- contraindicated with protease inhibitors b/c it can decrease protease inhibitor concentration
name the integrase inhibitors
- raltegravir
- elvitegravir
- dolutegravir
integrase inhibitors–mechanism
- inhibits HIV genome integration into host cell chromosome by reversibly inhibiting HIV integrase
integrease inhibitors–toxicity
- inc creatine kinase
name the fusion inhibitors
- enfuvirtide
- maraviroc
enfurvirtide–mechanism
- (fusion inhibitor)
- binds gp41 to inhibit viral entry
enfurvirtide–toxicity
- skin rxn at injection site
maraviroc–mechanism
- (fusion inhibitor)
- binds CCR-5 on surface of T cells/monocytes which inhibit interaction with gp120
interferons–mechanism
- glycoproteins normally synthesized by virus-infected cells
- exhibit a wide range of antiviral and antitumoral properties
INF alpha–use
- chronic hepatitis B and C
- Kaposi sarcoma
- hairy cell leukemia
- condyloma acuminatum
- renal cell carcinoma
- malignant melanoma
IFN beta–use
- multiple sclerosis
IFN gamma–use
- chronic granulomatous dz
interferon–toxicity
- flu like symptoms
- depression
- neutropenia
- myopathy
name the hepatitis C therapy drugs
- ribavirin
- sofosbuvir
- simeprevir
ribavirin–mechanism
- inhibits synthesis of guanine nucleotides by competitively inhibiting inosine monophosphate dehydrogenase
ribavirin–use
- chronic HCV
- also used in RSV
- palivizumab preffered in children
ribavirin–toxicity
- hemolytic anemia
- severe teratogen
sofosbuvir–mechanism
- inhibits HCV RNA dependent RNA polymerase acting as a chain terminator
sofosbuvir–use
- chronic HCV in combination with ribavirin
- +/- peginterferon alfa
- do not use as monotherapy
sofosbuvir–toxicity
- fatigue
- headache
- nausea
simeprevir–mechanism
- HCV protease inhibitor
- prevent viral replication
simeprevir–use
- chronic HCV in combination with ledipasvir (NS5A inhibitor)
- do not use as monotherapy
simeprevir–toxicity
- photosensitivity rxns
- rash
what is the goal of infection control techniques?
- reduction of pathogenic organism counts to safe levels–disinfection
- inactivation of self propagating biological entities–sterilization
list 5 infection control techniques
- autoclave
- alcohols
- chlorhexidine
- hydrogen peroxide
- iodine and iodophors
explain autoclave
- pressurized steam at > 120 deg C
- may be sporicidal
explain alcohols (as an infection control technique)
- denature proteins and disrupt cell membranes
- not sporicidal
explain chlorhexidine
- denatures proteins and disrupts cell membranes
- not sporicidal
explain hydrogen peroxide as an infection control technique
- free radical oxidation
- sporicidal
explain iodine and iodophors as an infection control technique
- halogenation of DNA, RNA, and proteins
- may be sporicidal
name tha antimicrobials to avoid during pregnancy
- Sulfonamides
- Aminoglycosides
- Fluoroquinolones
- Clarithromycin
- Tetracyclines
- Ribavirin
- Griseofluvin
-
Chloramphenicol
- “SAFe Children Take Really Good Care”
what is the adverse effec tof sulfonamides during pregnancy?
kernicterus
what is the adverse effect of aminoglycosides during pregnancy?
ototoxicity
what is the adverse effect of fluoroquinolones during pregnancy?
cartilage damage
what is the adverse effect of clarithromycin during pregnancy?
embryotoxic
what is the adverse effect of tetracyclines during pregnancy?
- discolored teeth
- inhibition of bone growth
what is the adverse effect of ribavirin during pregnancy?
teratogenic
what is the adverse effect of griseofulvin during pregnancy?
teratogenic
what is the adverse effect of chloramphenicol during pregnancy?
Gray baby syndrome