Pharm2Exam3 Flashcards
Beta Lactams
Penicillins Cephalosporins Carbapenems Monobactams Beta-Lactamase Inhibitors
Penicillins (drugs)
Penicillin G (IV) Penicillin V (PO)
Penicillin Coverage
Streptococcus
Syphilis
Aminopenicillins (drugs)
Amoxicillin
Ampicillin
Penicillin Pharm
Protein bound
low BV (poor diffusion) low CSF, brain, prostate, eye, etc. concentration
Little hepatic metabolism
Eliminated renally
Amoxicillin Spectrum
Strep, no staph, Enterococcus faecalis, no MRSA, no G-, Haemophilius influenzae (G-)
Ampicillin Spectrum
Strep, no staph, Enterococcus faecalis, Listeria, no G-, Haemophilius influenzae (G-)
Anti-staphylococcal Penicillins (drugs)
Methicillin
Nafcillin
Oxacillin
Dicloxacillin
Anti-staph penicillin coverage
Staph, strep, no Enterococcus, No MRSA, little G-
Extended Spectrum penicillins
Piperacillin
Ticarcillin
Extended Spectrum penicillin coverage
Streph, minimal staph, Enterococcus faecalis, No MRSA, G- coverage**, Pseudomonas, some anaerobes
Beta-lactamase inhibitors (drugs)
Amoxicillin/Clavulanate
Ampicillin/Sulbactam
Pipercillin/Tazobactam
Ticarcillin/Clavulanate
Amoxicillin/Clavulanate
Staph, strep, E. facealis, G-! Neisseria, E coli, Proteus, Morexella, Hemophilus influenzae, Klebsiella, and anaerobes
Amoxicillin/Clavulanate
Staph, strep, E. facealis, G-! Neisseria, E coli, Proteus, Morexella, Hemophilus influenzae, Klebsiella, and anaerobes
Ampicillin/Sulbactam
Similar to amoxicillin/clavulanate + acinetobacter
Piperacillin/Tazobactam
Beta-lactamase inhibitor
Staph. strep, E faecalis, no MRSA, broad G-***, pseudomonas, anaerobes
Ticarcillin/clavulanate
Same as pipercillin/tazobactam
Penicillin Tox
Mainly tolerable *Allergies - anaphylaxis, urticaria, fever, swelling, hemolytic anemia, vasculitis Penicillin: Seizures* Nafcillin: Myelosuppression Oxacillin: Hepatitis *Large PO doses = GI tox
Beta-lactam Resistance Mech.
Altered PBPs, reduced permeability, Beta-lactamases
Type 1 Beta Lactamase
Cephalosporinase
Hydrolyzes: beta-lactamase inhibitor/beta-lactam combo drugs, penicillins, 1/2/3 gen cephalosporins, monobactams
Treatments: Imipenem, fluoroquinolones, and cefepime
Type II Beta Lactamase
Extended Spectrum Beta-lactamases
Hydrolyzes: cephalosporins (except cefoxitin, cefmetazole, and cefotetan), Aztreonam, Extended spectrum penicillins!, combo penicillins kind of work
Treatment: Carbapenems, Non-beta lactams, Cephamycins
Type III Beta Lactamases
Metallo-beta-lactamases
Hydrolyzes: Carbapenems!!, older penicillins, cefotaxime, ceftriaxone
Treatment: Piperacillin, ceftazidime, some combo penicillins
1st Gen cephalosporins
Cefazolin
cephalexin
Cefadroxil
1st Gen cephalo Spectrum
NO ENTERO, staph, strep, NO MRSA, G-: proteus, e coli, klebsiella
1st Gen cephalo Spectrum
NO ENTERO, staph, strep, NO MRSA, G-: proteus, e coli, klebsiella
2nd Gen Cephalosporins
Cefuroxime Cefaclor Cefprozil Cefoxitin Cefotetan Cefmetazole Cefimandole
2nd gen Cephalo spectrum
staph, strep, no entero, less G+ that 1st gen, no MRSA, G-: HENPEK
3rd gen Cephalosporins
Ceftriaxone Ceftazidime* Cefoperazone* Cefixime Cefdinir Cefpodoxime Ceftibuten * Pseudomonas
3rd gen cephalos spectrum
Steph, strep, no entero, less than 1st or 2nd gen (G+), G-: HENPEK + Serratia, Citrobacter, Acinetobacter, Morganella, Providencia
4th generation Cephalosporin
Cefepime (broadest spectrum cephalo)
Cefepime
4th gen cephalo
Staph, Strep, no Entero, G-: broad G-, +pseudomonas
5th generation Cephalosporin
Ceftaroline
Ceftaroline
Staph, MRSA**, Strep, Entero (minimal)
Cephalosporin Tox
Mostly tolerated
Most common = allergy: anaphylaxis, urticaria, fever, swelling, etc.
Hemolytic anema, interstitial nephritis, vasculitis
Long term = myelosupression, large PO = GI tox
Cefotetan, Cefmetazole, and Cefimandole = antabuse reaction, platelet dysfunction (bleeding)
Carbapenem Pharm
All eliminated in the urine (Imipenem: brush border dihydropeptidase to inactive metabolite)
Some liver metabolism (meropenem and Doripenem)
Good CSF penetration with meropenem
Otherwise similar to penicillins
Carbapenems (drugs)
Imipenem/Cilastatin* Meropenem*+ Doripenem*+ Ertapenem - no pseudomonas or entero *Pseudomonas \+minimal E. Faecalis
Carbapenem spectrum
Staph, Strep, no MRSA, no E faecium, no VRE
G- = broad spectrum, + pseudomonas, anaerobes
Carbapenem Tox
mostly tolerable
Seizures (neurotox)
most common = allergy (anaphylaxis, urticaria, fever, swelling)
Aztreonam
Monobactam
metabolism via liver, and renal exclusion. CSF penetration.
No IgE mediated cross-reactivity with beta-lactams except Ceftazidime.
Aztreonam spectrum
Similar to aminoglycosides
No G+
Broad G- coverage, pseudomonas
Aztreonam Tox
No penicillin allergy reaction
Well tolerated
Hepatoxicity
Allergy non-related to penicillin allergy
Glycopeptides
Vancomycin
Teicoplanin
Vancomycin/Telavancin MOA
MOA: inhibits transglycosylases preventing peptidoglycan cross linking, disrupts cell membrane resulting in loss of membrane potential
Pharm: No PO, IV only. Poor penetration CSF, brain, eye, prostate, lung, etc. Almost 100% renal eliminated
Glycopeptide Spectrum
G+: Staph, MRSA! Strep, Entero, no VRE, Clostridium difficile
NO G-
Glycopeptide Spectrum
G+: Staph, MRSA! Strep, Entero, no VRE, Clostridium difficile
NO G-
Lipoglycopeptides
Telavancin
Dalbavancin
Glycopeptide Resistance
Alteration in peptidoglycan target
Glycopeptide TOX
Tissue irritation, infusion related rxn Collitis, Rare: nephrotoxicity, ototoxicity
Polymyxins (drugs)
Polymyxin B
Polymyxin E
Colistimethate (prodrug)
Polymyxins MOA
Cationic detergent disrupts PM
Polymyxins Pharm
No PO, Renally eliminated
Polymyxins Spectrum
Broad G-, no Proteus (slimey membrane)
Polymyxins Resistance
Cell wall alterations (Thickening), PM alterations (slimey), Cell envelope protection by PM.
Polymyxins TOX
Nephrotoxicity, Neurotoxicity
Cyclic lipopeptides
Daptomycin
Daptomycin
Cyclic lipopeptides
MOA: Ca dependent insertion into PM = K+ efflux resulting in loss of membrane potential.
Pharm: no PO, renal elimination
Daptomycin Spectrum
G+: MSSA, MRSA, Staph, Strep, Entero, VRE!!!
NO G-
Daptomycin resistance
Alteration to reduce binding to PM
Daptomycin TOX
Muscle tox - rare Rabhdomyolysis (monitor CDK)
Aminoglycosides MOA
Binds 30S ribosomal subunit and prevents binding of 50S, inhibiting initiation of coding or miscoding effecting translocation.
Aminoglycoside pharm
Hexose ring, streptidine - streptomycin
more active in alkaline environments
Post-antibiotic effect! (bacteriocidal even under MIC)
O2 dependent
No PO, hydrophilic, poor penetration: CSF, brain, eye, prostate, lung, etc.
Eliminated via urine
Aminoglycoside Agents
Streptomycin Gentamicin Tobramycin Netilmicin Amikacin Spectinomycin
Aminoglycoside Spectrum
G+ = minimal staph, synergy with beta-lactams and vanco against strep, staph, and entero, synergy against listeria (thick CW no PM penetration to get to ribosome)
G-: broad coverage, pseudomonas
Atypical: Nocardia, tuberculosis, Neisseria
Aminoglycoside Resistance
Modifying enzyme inactivation, reduced permeability, altered ribosome to prevent binding
1,2,3 acetyltransferase
4 phosphotransferase
5 adenylyltransferase
*Amikacin is resistant to modification at 2, 3, 4, 5 (only susceptible at 1 and enzyme that modifies is less common)
Aminoglycoside TOX
Hypersensitivity (rare) - except topical neomycin
Nephrotoxicity
Ototoxicity - auditory and vestibular (balance loss)
At high dose: neuromuscular blockade
Tetracycline MOA
Binds to 30S ribosomal subunit with inhibits protein synthesis (similar to aminoglycosides)
Tetracycline pharm
well absorbed PO, short half-life, PM permeable, penetrate most tissues well
Tetracycline drugs
Tetracycline
Doxycycline
Minocycline
Demeclocycline
Tetracycline Spectrum
Strep, Staph, NO entero, Listeria, Neisseria, Moraxella, Hemophilus, Atypical: Legionella, mycoplasma, chlamydia, Rickettsia
Tigecycline
Glycylcycline
G+: Strep, Staph, Entero, VRE, Listeria
G-: broad coverage, except the 3 P’s: Pseudomonas, Proteus, Providencia
Atypicals: Legionella, Mycoplasma, chlamydia, Rickettsia
Tetracycline Resistance
Altered permeability, Altered ribosomal binding, Enzymatic inactivation of tetracycline
Tetracycline TOX
rare hypersensitivity, GI tox, tetra teeth, bone deformities (kids), hepatoxicity, nephrotoxicity, photosensitivity, vestibular tox (NR), tissue injury (IV infusion)
Chloramphenicol
MOA: Different! Reversibly binds the 50S subunit of the 70S ribosome inhibiting protein synthesis
Pharm: absorbed PO, high levels orally lipophilic does not solublize well. Metabolized by liver, no renal. Penetrates CSF well
Chloramphenicol Spectrum
Broad G+, poor staph coverage, broad G- poor pseudomonas coverage, anaerobes, atypicals: rickettsia
Chloramphenicol Resistance
Alterations in PM permeability, Enzymatic inactivation of drug - chloramphenicol acetyltranferase
Chloramphenicol Tox
A LOT
GI, Hematologic**, myelosuppression, aplastic anemia (irreversible and idosyncratic)
Gray syndrome (neonates can not glucuronidate drug)
Optic neuritis: visual issues both reversible and irreversible.
Macrolides
MOA: lipophilic = good penetration but no IV formula
binds the 23S ribosomal subunit on 50S ribosome inhibiting protein synthesis
Pharm: water insoluble, Erythromicin is acid labile (unstable in stomach acid). Crosses BBB
Macrolides drugs
Erythromycin
Azithromycin
Clarithromycin
Dirithromycin
Macrolide spectrum
G+: strep, staph, no VRE, Listeria, some MRSA
G-: Morexella, Hemophilus
Atypical: mycoplasma, legionella, chlamydia, rickettsia, syphilis
Strep/staph: Clarithro>erythro>azithro
Macrolide Resistance
Alteration of the ribosome (methylation of RNA target)
Efflux pumps
Enzymatic inactivation of drug
Macrolide Tox
Hypersensitivity - uncommon
GI**
Hepatotoxicity = ^^ liver metabolites
Ketolides
Semi-synthetic 14-member macrolides
Increased stability to acid
Similar spectrum to macrolides
Similar macrolide tox - higher hepatotoxicity
Lincosamides
Clindamycin
MOA: bind the 50S subunit of the 70S ribosome inhibits protein synthesis
Clindamycin Pharm
Well absorbed PO, poor CSF/brain penetration, metabolized by the liver* (= hepatotox)
Clindamycin spectrum
G+: Strep, staph, no entero
Anaerobes
Clindamycin Resistance
Enzymatic inactivation of the drug
Alteration of the ribosome (mutation of receptor site or methylation of the ribosome to prevent drug binding)
Clindamycin Tox
Hypersensitivity (not adverse)
GI
Hepatotoxicity
myelosuppression (chronic use) neutropenia
Oxazolidinones
Linezolid
Linezolid
Oxazolidinone
MOA: inhibits protein synthesis by binding 23S subunit
Pharm: well absorbed PO, hepatic metabolism, almost 100% BA
Linezolid spectrum
MSSA, MRSA, coagulase (-) staph, strep, entero, VRE
NO G-
Linezolid Resistance
Mutation in 23S binding site
Linezolid Tox
myelosuppression (reversible), optic neuritis, peripheral neuropathy (Irreversible), lactic acidosis (mitochondrial tox)
Protein synthesis inhibitors
Aminoglycosides: Streptomycin, Gentamicin, Tobramycin, Netilmicin, Neomycin, Amikacin, Spectinomycin
Tetracyclines: Tetracycline, Doxycycline, Minocycline, Demeclocycline
Glycylcyclines: Tigecycline
Chloramphenicol
Macrolides: Erythromycin, Azithromycin, Clarithromycin, Dirithromycin
Ketolides
Lincosamides: Clindamycin
Oxazolidinones: Linezolid
30S binding - protein synth inhibitors
Aminoglycosides
Tetracyclines
50S binding - protein synth inhibitors
Chloramphenicol
Lincosamides
23S binding - protein synth inhibitors
Macrolides
ketolides
Oxazolidinones
23S binding - protein synth inhibitors
Macrolides
ketolides
Oxazolidinones
Sulfonamides
MOA: inhibit the conversion of PABA to dihydrofolic acid by inhibiting the enzyme dihydropteroate synthase
Pharm: Well absorbed orally, highly lipophilic. Penetrates tissues well including brain and CSF
Acetylated and glucuronidated in the liver (increased water solubility) then excreted in urine
Sulfonamides drugs
Sulfacytine Sulfisoxazole Sulfamethizole Sulfadiazine* Sulfamethoxazole* (SMX) Sulfapyridine Sulfadoxine
Pyrimidines (Sulfonamides)
Trimethoprim
Trimethoprim (TMP)
Inhibits conversion from dihydrofolic acid to trihydrofolic acid via enzyme dihydrofolate reductase
Synergistic effect with sulfonamides – they inhibit PABA conversion via different MOA
Sulfonamide Resistance
Altered enzymes
Overproduction of PABA (overcome inhibition)
Alteration in permeability
Sulfonamide TOX
Hypersensitivity (2nd most common)
Photosensitivity, Nephrotox: allergic nephritis, Precipitation in urine (hematuria, crystalluria, renal damage), anemia (hemolytic, aplastic), Kernicterus, GI, Hepatotox
TMP/SMX spectrum
G+: minimal strep, staph, some MRSA, Listeria, no Entero
G-: Nieserria, morexella, hemophilus, E coli, Klebsiella, Stenotrophomonas maltophilia, Yersinia, F tularensis, Brucella
Atypical: PCP, Nocardia
*Niche or uncommon pathogens
Trimethoprim resistance
Alterations in permeability, overproduction of dihydrofolate reductase, alterations in dihydrofolate reductase
TMP/SMX tox
Same as sulfonamide tox except more anemia, including megaloblastic
Fluoroquinolones
MOA: effects topoisomerase I and II, inhibit nicking and closing activity
Pharm: absorbed PO, absorption decreased when given with cations (Ca, Mg, Fe, Cu, etc)
penetrates well
Fluoroquinolones
MOA: effects topoisomerase I and II, inhibit nicking and closing activity
Pharm: absorbed PO, absorption decreased when given with cations (Ca, Mg, Fe, Cu, etc)
penetrates well
Fluoroquinolones (drugs)
Ciprofloxacin Gatifloxacin Gemifloxacin Levofloxacin Moxifloxacin Norfloxacin Ofloxacin Lomefloxacin
Fluoroquinolones spectrum
G+: staph, strep, no entero (except Cipro)
G-: good coverage, +pseudomonas
Anaerobic in Gati and Moxi only
Atypical: mycoplasma, legionella, chlamydia, mycobacterium
Fluoroquinolone Resistance
Altered DNA gyrase target
Efflux pump or reduced PM permeability
Fluoroquinolone Tox
Hypersensitivity, GI, CNS tox (more in elderly), hepatox (uncommon), alterations in glucose (Gatifloxacin), QTc prolongation, tendon rupture (athletes), arthropathy
Sulfonamides drugs
Sulfacytine Sulfisoxazole Sulfamethizole Sulfadiazine* Sulfamethoxazole* (SMX) Sulfapyridine Sulfadoxine
Fluoroquinolones (drugs)
Ciprofloxacin Gatifloxacin Gemifloxacin Levofloxacin Moxifloxacin Norfloxacin Ofloxacin Lomefloxacin
Nucleic Acid Inhibitors
Sulfonamides: Sulfacytine, Sulfisoxazole, Sulfamethizole, Sulfadiazine, Sulfamethoxazole (SMX), Sulfapyridine, Sulfadoxine
Trimethoprim
Fluoroquinolones: Ciprofloxacin, Gatifloxacin, Gemifloxacin, Levofloxacin, Moxifloxacin, Norfloxacin, Ofloxacin, Lomefloxacin
Anti-Fungals
Polyenes: Amphotericin B, Nystatin (not systemic)
Flucytosine
Azoles: Fluconazole, Itraconazole, Voriconazole, Posaconazole
Echinocandins: Capsofungin, Micafungin, Anidulafungin
Griseofulvin
Terbinafine
Tolnaftate
Saturated Solution of Potassium Iodide (SSKI)
Polyenes MOA
Bind ergosterol in fungal PM. A potassium channel is formed causing an efflux of K and loss of PM potential
Ergosterol is inhibited (PM instability)
Polyenes Pharm
Not absorbed well PO, and insoluble in water. Must be complexed in colloidal suspension with bile acid salt to make water soluble for IV use.
Hepatic and renal elimination
Penetrates tissues well, concentrates in liver, spleen and kidney
Long 1/2 life, once/day dose (can accumulate in bone)
Amphotericin B agents/spectrum
Liposomal and lipid complex Amph. B have decreases nephrotoxicity and side effects.
Spec: Candida (minus lusitaniae), Aspergillus, Histoplasma, Blastomyces, Coccidioides, Zygomycetes
Lipid Amphotericin B
Lower toxicity, but less evidence
*Used in patient that won’t tolerate regular Amph-B, or those at high risk for adverse events (renal compromised patients!!)
Amph-B resistance
Impaired Ergosterol binding:
decreasing ergosterol in PM or altered ergosterol target
Amph-B tox
**Nephrotoxicity! (long term use)– electrolyte wasting (K and Mg need to supplement) and bicarbonate wasting
Need to monitor renal fxn and electrolytes
Renal vasospasm: ischemia, decrease GFR and increased creatinine (duration and dose dependent, reversible)
Infusion reactions
Anemia
Nystatin
Polyene
Very high nephrotoxicity, only use PO and topical, not systemic
Flucytosine MOA
MOA: converted to 5-FU, and then FdUMP and FUTP which inhibit DNA and RNA synthesis respectively
Flucytosine Pharm
absorbed PO, renal elimination, penetrate tissue well CSF/brain
Flucytosine Spectrum
Cryptococcus neoformans
Candida (not often used)
Flucytosine Resistance
Can develop quickly– often used with other anti-fungal drugs
Altered metabolism of flucytosine (must become triphosphorylated)
Azoles MOA
imidazoles have only 2 N groups, triazoles have 3 N groups
Imidazoles are less fungal selective and cause more tox
Triazoles are more selective with less tox
Azole work by inhibiting lanosterol 14-a-demethylase = decreases ergosterol synthesis
Decreased ergosterol = unstable PM
*decreases efficacy of Amph-B
Azole Pharm
Triazoles have greater affinity for fungal cells than mammalian cells = less tox
Drug intxns! - induction or inhibition of drug metabolism thru CYP450 enzymes
Azole drugs
Fluconazole
Itraconazole
Voriconazole
Posaconazole
Azole drugs
Fluconazole
Itraconazole
Voriconazole
Posaconazole
Fluconazole
Azole anti-fungal
IV and PO
Hepatic metabolism, renal elimination (only 10% is metabolites, 90% unchanged drug in kidney BAD, requires adjustment in renally compromised patients)
Penetrate CSF/tissues
USE: Dermatophytes, cryptococosis, candidiasis, coccidiodes
Tox: GI, hepatotox, alopecia*
Itraconazole
Azole anti-fungal
IV and PO decreased oral absorption with increased stomach pH - don’t use PPI’s or antacids before use
metabolized in liver
good tissue/CSF penetration
USE: dermophytes, onychomycosis, blastomycosis, histoplasmosis
Tox: GI, Hepatotox, mineral corticoid excess, negative inotropy* (low EF and heart fxn, can increase BP with fluids)
Voriconazole
Azole anti-fungal
IV and PO
Long 1/2 life
Metabolized hepatically
penetrate tissue/CSF well
USE: aspergillus, candidiasis, blastomycosis, histoplasmosis
TOX: GI, hepatotox, visual changes* (rule of 30s), photosensitivity*
Posaconazole
azole anti-fungal PO only liver metabolized penetrates well USE: "BAD molds": aspergillus, candidiasis, blastomycosis, histoplasmosis, zygomycectes TOX: no significant, GI, and hepatotox
Posaconazole
azole anti-fungal PO only liver metabolized penetrates well USE: "BAD molds": aspergillus, candidiasis, blastomycosis, histoplasmosis, zygomycectes TOX: no significant, GI, and hepatotox
Azole resistance
Increased efflux of azole
Over expression of lanosterol 14-a-demethylase (overcomes inhibition of ergosterol synthesis)
point mutation leading to decreases affinity of azoles for lanosterol
Echinocandin MOA
inhibit beta-glucan synthase preventing synthesis of beta-glucan resulting in weak cell wall and structural instability
Echinocandin pharm
Not absorbed orally, IV only (large cyclic peptides)
metabolized in situ
Hepatic metabolism (capsofungin and Micafungin)
Echinocandin Spectrum
Candidas and Aspergillus ONLY
minus C. parapsilosis due to high MIC required
Echinocandin Resistance
Mutation at Beta-(1,3)-glucan preventing synth inhibition
Up-regulation of chitin synthesis, makes up for beta-glucan loss.
Echinocandin Tox
Histamine release during infusion
hypersensitivity
hypokalemia
hepatotoxicity (increase ALT/AST with cyclosporines)
Echinocandin drugs
Capsofungin
Micafungin
Anidulafungin
Griseofulvin
anti-fungal
MOA: inhibits fungal mitosis by binding microtubules disrupting mitotic spindle
binds keratin precursor cells, preventing new nails from infection
Tox: GI, (not as used due to replacement therapy)
Terbinafine
Anti-fungal
MOA: Allylamine inhibits ergosterol synthesis (enzyme squalene epoxidase)
Topical and oral only
Use: skin/nail infections, athletes foot/ skin-skin infections
Tox: hepatitis, and hepatotoxicity
Tolnaftate
Anti-fungal
MOA: thiocarbamate, topical
USE: limited spectrum, Tinea infections
-don’t need to know much
Saturated Solution of Potassium Iodide (SSKI)
Anti-fungal
Oral solution
TOX: nausea, bitter emesis, hypersalivation
USE: former treatment of Sporotrichosis (now itraconazole)
Anti-Herpes agents
Acyclovir Valacyclovir Famciclovir Penciclovir Docosanol Trifluridine
Anti-herpes agents MOA
*Must be triphosporylated to work (to look like NTPs)
Acyclovir and Penciclovir require all 3 phosphorylations, first by virus-specific enzymes, thymidine kinase, (point of resistance) and the 2nd and 3rd phosphorylation are by mammalian enzymes
Trifluridine, cidofovir, and foscarnet already have 1st phosphate, so they can bypass the viral kinase step directly phophorylated by mammalian kinases.
After activation, drug is either directly bound to DNA polymerase to prevent replication or incorporated into DNA resulting in early termination.
Acyclovir
Anti-herpes Acyclic guanosine derivative HSV-1 HSV-2 and VZV MOA: requires 3 phosphorylations, prevents or terminates DNA synthesis IV and PO Renal elimination, minimal hepatic Penetrates most tissues
Acyclovir Resistance
Alteration of thymidine kinase
Alteration in DNA polymerase
Acyclovir TOX
GI
nephrotox - must be renally adjusted
Neurotox - tremors, delirium, seizures, AMS
Famciclovir
Anti-herpes Prodrug of penciclovir Hepatically metabolized HSV-1 HSV-2 and VZV MOA: requires 3 phosphorylation to inhibit DNA synthesis
Famciclovir Resistance
Alteration in thymidine Kinase
Famciclovir TOX
GI, less nephro- and neurotox
concentration dependent
Valacyclovir
Anti-herpes
Prodrug of acyclovir - hydrolyzed to acyclovir in liver/intestine
improved PO absorbance
Same resistance/tox as acyclovir
Penciclovir
Anti-herpes agent
Active metabolite of famciclovir
Topical only
treatment of oral herpes
Docosanol
Anti-herpes agent USE: HSV-1 and HSV-2 MOA: inhibits fusion of PM and viral envelope Topical Tox: minimal
Trifluridine
Fluorinated pyrimidine nucleoside
Use: HSV-1, HSV-2, CMV
MOA: phosphorylated intracellularly by host enzymes, then competes with thymidine triphosphate for incorporation by viral DNA polymerase
Cytomegalovirus agents
Ganciclovir
Valganciclovir
Foscarnet
Cidofovir
Cytomegalovirus agents MOA
Same as anti-herpes agents
Ganciclovir needs all 3 phosphorylations, relies on protein kinase phosphotransferase (UL97).
Cidofovir and Foscarnet come with 1 phosphate group, do not rely on thimidine kinase and are directly phosphorylated by host enzymes
Ganciclovir
CMV agent acyclic guanosine derivative Use: CMV, HSV1, HSV2 and VZV MOA: requires 3 phosphorylations to be active and inhibit DNA synthesis (protein kinase UL97) IV and PO, poor oral absorption Renally eliminated Penetrates most tissues
Ganciclovir Resistance
Alterations in protein kinase (UL97)
Alteration in DNA polymerase (UL54)
Ganciclovir TOX
GI myelosuppression - leukopenia hepatotoxicity Teratogenic** Neurotox - (more without renal adjustment)
Valganciclovir
CMV agent
Ganciclovir plus valine group (improved BA)
acyclic guanosine derivative
USE: CMV, HSV1, HSV2, VZV
100x more active against CMV than acyclovir
MOA: Requires 3 phosphorylation steps to be active
1st phosphate group added by protein kinase phosphotransferase UL97
Only PO renally eliminated
Penetrates most tissue - no CNS
Valganciclovir Resistance
Alteration of UL97
Alteration in DNA polymerase (UL54)
Valganciclovir TOX
GI Myelosuppression hepatotox teratogenic neurotox Same as ganciclocvir
Foscarnet
CMV agent MOA: does not require viral enzyme for 1st phosphorylation, inhibits DNA polymerase, RNA polymerase, HIV reverse transcriptase Use: HSV1, HSV2, VZV, CMV, EBV, HIV-1 IV only penetrate +CNS Renal elimination
Foscarnet Resistance
Point mutation in DNA polymerase and HIV reverse transcriptase
Foscarnet Tox
Nephrotox - serum creatinine and must monitor electrolytes Electrolyte disturbances GI Hepatotox CNS Infusion arrhythmias, numbness, tingling
Cidofovir
CMV agent
HIGHLY NEPHROTOXIC
acyclic cytosine analog
MOA: does not require first phosphorylation, independent of protein kinase. Inhibits DNA polymerase, or incorporated into DNA.
Use: CMV, HSV1, HSV2, VZV, EBV, polyomavirus
Poor CNS penetration
Renally eliminated
Cidofovir Resistance
Point mutation in DNA polymerase (no UL97)
*Cidofovir resistance isolates are usually also resistant to ganciclovir, but susceptible to foscarnet
Cidofovir resistance predicts foscarnet resistance but not the other way around!
Cidofovir Tox
Nephrotox!!
Ocular tox
neutropenia
Mutagenic, gonadotoxic, and embryotoxic (infertility)
NRTI drugs
HIV agents Abacavir Didanosine Emtricitabine Lamivudine Stavudine Tenofovir Zidovudine
NNRTI drugs
HIV agents Nevirapine Delavirdine Efavirenz Etravirine Rilpivirine
NRTIs
Looks like nucleoside/nucleotides
Need to be triphosphorylated to be active
Same as guanaline analogs
= early termination or direct inhibition of enzymes
NRTIs
Looks like nucleoside/nucleotides
Need to be triphosphorylated to be active
Same as guanaline analogs
= early termination or direct inhibition of enzymes
MOA: competitive inhibition of HIV-1 reverse transcriptase, incorporation into growing viral DNA chain = termination
Hepatic and renal elimination
NRTIs TOX
Mitochondrial tox (inhibits mitochondrial DNA polymerase gamma), lactic acidosis, hepatotoxicity
NNRTIs
Bind directly to HIV-1 reverse transcriptase, DO NOT require phosphorylation
Hepatically metabolized
NNRTI tox
GI, skin rash
Liver enzyme induced drug interactions! CYP450
Protease Inhibitors
Atazanavir Darunavir Fosamprenavir Indinavir Lopinavir/ritonavir Nelfinavir Ritonavir Saquinavir Tipranavir
Protease Inhibitor MOA
Prevents post-translational cleavage of the Gag-Pol polyprotein = prevents processing of viral proteins into functional conformations, or results in production of immature/non-infectious particles
Do not require intracellular activation
Hepatic metabolism
Protease Inhibitor Tox
Redistribution of body fat - peripheral and facial fat wasting, central obesity, buffalo hump, breast enlargement Hyperlipidemia Hyperglycemia, diabetes Osteoporosis Live enzyme drug interactions, CYP450
Entry inhibitors
HIV agent
CCR5 Antagonist: Maraviroc
Fusion inhibitor: Enfuvirtide
Maraviroc MOA
Binds CCR5 entry of CCR5 tropic HIV
Co-receptors are necessary for the entrance of HIV into CD4 cells: CCR5 CXCR4
HIV has 2 receptors, one of each, or both or one or the other
**Only active against CCR5 + CCR5 HIV
Hepatically metabolized
Not 1st line, only for resistance HIV with CCR5/CCR5 receptors
Maraviroc Resistance
Mutation in CCR5 receptor
Presence of non-CCR5 tropic HIV
Maraviroc TOX
Cough Respiratory problems Muscle/joint pain Diarrhea Sleep disturbances** Hepatotox
Enfuvirtide
MOA: inhibits HIV entry into cell by binding gp41
metabolized via proteolytic hydrolysis
Resistance: mutations in gp41 codon, no cross-resistance
TOX: injection site reactions, hypersensitivity
Intergrase Inhibitor
Raltegravir
Dolutegravir
Elvitegravir
Intergrase Inhibitors
HIV agents
Pyrimidinone analog
MOA: binds intergrase which inhibits strand transfer thus interfering with integration of reverse transcribed viral DNA into the chromosome of the host cell
Drug is glucuronidated, liver metabolism but not CYP450.
Glucuronidated = increased water solubility.
Intergrase Inhibitors
HIV agents
Pyrimidinone analog
MOA: binds intergrase which inhibits strand transfer thus interfering with integration of reverse transcribed viral DNA into the chromosome of the host cell
Drug is glucuronidated, liver metabolism but not CYP450.
Glucuronidated = increased water solubility.
Intergrase Inhibitors Resistance
Mutations in intergrase
Intergrase Inhibitors Resistance
Mutations in intergrase
1st line Anti-mycobacterials
Isoniazid Rifampin Ethambutol Pyrazinamide Streptomycin
2nd line Anti-mycobacterials
Amikacin Aminosalicylic Acid Capreomycin Ciprofloxacin Clofazamine Cycloserine Ethionamide Levofloxacin Rifabutin Rifapentine
Isoniazid
Anti-mycobacterial Prodrug MOA: most active against M tuberculosis. Inhibits the synthesis of mycolic acid Bactericidal Hepatically metabolized
Isoniazid Resistance
Point mutations in katG (low level - effective at higher doses)
Large mutation or deletion in katG (high level - no efficacy)
Mutations in inhA (low level resistance)
Isoniazid Toxicity
Hepatotox** significant drug interactions, minor increases in liver enzymes, hepatitis/liver failure
Neurotox - peripheral neuropathy due to clearance of pyridoxine (usually supplemented)
Hypersensitivity rxn
Isoniazid OD
Large doses = metabolic acidosis, hyperglycemia, Seizures, coma
Rifampin
Anti-mycobacterial MOA: binds to beta subunit of bacterial DNA dependent RNA polymerase and inhibits RNA synthesis Bactericidal Penetrates tissues Hepatically metabolized
Rifampin Resistance
Mutations in rpoB - gene for beta subunit of RNA polymerase.
Rifampin TOX
Hepatotox - hepatitis, drug interactions*, failure (fatal)
Nephrotox - nephritis, acute tubular necrosis (rare)
Hypersensitivity
Orange body fluid discoloration
Flu-like symptoms - more common with high dose/intermittent therapy
Ethambutol
Anti-mycobacterial
MOA: inhibits arabinosyl transferase enzyme involved in arabinogalactan biosynthesis within cell wall, = instability
*bacteriostatic
Hepatically metabolized
Ethambutol Resistance
The embCAB operon codes for synthesis of arabinogalactan and lipoarabinogalactan (overcomes inhibition of enzymes)
Mutations in emb = loss of ethambutol activity
Ethambutol TOX
Optic Neuritis (larger doses) Hypersensitivity rxn
Pyrazinamide
Anti-microbacterial
MOA: synthetic analog of nicotinamide. prodrug- must be converted to pyrazanoic acid to be active. MOA unknown
Bactericidal
Hepatically metabolized
Pyrazinamide Resistance
Mutations in pncA (codes for pyrazinamidase) = decreased activation of pyrazinamide into pyrazanoic acid = decreased concentration)
Pyrazinamide TOX
Hepatotox N/V Polyarthalgias* (joint pain) Nephrotoxicity Hypersensitivity Urate retention (exacerbates gout) Photosensitivity