Antimicrobials: Protein Synthesis Inhibitors Flashcards
Inhibits formation of initiation complex
Aminoglycosides
Inhibits amino acid incorporation
Tetracycline
Inhibits formation of peptide bond
Chloramphenicol
Inhibits translocation
Macrolides
Lincosamide (Clindamycin)
Agents that bind to 30s ribosomal subunit
Aminoglycoside
Tetracycline
Agents that bind to 50s ribosomal subunits
Macrolides
Chloramphenicol
Lincosamide
Bactericidal
Aminoglycoside
Cell wall synthesis inhibitors
Bacteriostatic
Tetracycline
Macrolide
Chloramphenicol
Lincosamide
“mycin”
Derived from streptomyces
“Micin”
Derived from micromonospora
Inhibits protein synthesis at the 30s ribosomal subunit
Excreted unchanged by
Aminoglycoside
kidneys
Aminoglycoside examples
Excreted unchanged by kidneys
Amikacin Netilmicin Neomycin Tobramycin Gentamicin Streptomycin
TANGS
For UTI Gram negatives
Combined with penicillin and cephalosporin and or anti anaerobe E coli Enterobacter Klebsiella Pseudomonas Tularemia
Aminoglycosides
DOC for tularemia
Streptomycin
Synergistic with beta lactam antibiotics
Bactericidal
Highly polar structure prevents adequate absorption after oral administration
All must be given IV to achieve serum levels except neomycin
Aminoglycoside
Only aminoglycoside given topically or orally
Neomycin
Aminoglycosides cause
Ototixicity
Nephrotoxicity
as well as Cisplatin
Aminoglycosides are bactericidal because
1 they bind to outer bacterial membrane thereby disrupting membrane integrity
2 bind to ribosomal 30s subunit
Interferes formation of initiation complex
Induce misreading of mRNA template
Cause polysomes to break up into monosomes
Concentration-dependent killing
Binding to 30s ribosomal subunit
Aminoglycosides
Explains why aminoglycosides can be given in single daily doses despite short half-life
Concentration dependent (post antibiotic effect)
2 days fluid diet, mechanical
Oral Metronidazole and Erythromycin 1 g and Neomycin
Nichols-Codon Bowel Prep for Colorectal Surgery
Aminoglycoside adverse effects:
Ototoxicity
Nephrotoxicity - Acute Tubular Necrosis
Neuromuscular blockade
“triple punch of a mean guy”
Aminoglycosides cause ototoxicity and nephrotoxicity because
they accumulate in the endolymph of the inner ear causing damage to hair cells in cochlea
and renal cortex
this is increased when taking diuretics
Aminoglycosides cause nephrotoxicity because
they accumulate in the renal cortex
Aminoglycosides cause neuromuscular blockade because
they decrease acetylcholine and decrease sensitivity to postsynaptic site
Aminoglycoside-induced neuromuscular blockade is reversed by
Ca gluconate
Neostigmine
Broadest spectrum of activity
Tetracycline
Activity against gram positive Gram negative Spirochetes Mycoplasma Rickettsia Chlamydia
Tetracyclines
Contains four fused rings with a system of conjugated double bonds
Inhibits protein synthesis at 30s ribosomal subunit
Tetracyclines
Tetracyclines Cannot be given with milk and antacids because
They form stable complexes with divalent and trivalent cations. Divalent cations inhibit its absorption in the gut.
Tetracylines cause Milk Alkali Syndrome:
Hypercalcemia
Alkalosis
Renal failure
inc Ca
inc pH
Renal failure
DOC for vibrio cholerae
Tetracycline
DOC for Mycoplasma
Macrolide
DOC for Rickettsia
Tetracycline
Covers Vibrio cholerae Acne Chlamydia Ureaplasma Urealyticum Mycoplasma Borrelia burgdorferi (Lyme disease) Rickettsia
Tetracycline
VACUUM your Bed Room
For psittacosis inclusion conjunctivitis trachoma endocervical rectal infection and non specific urethritis
all by Chlamydia
Tetracycline
DOC in syphillis if allergic to penicillin
Tetracycline
For Brucellosis
Cholera
Acne
Tetracycline
Most common adverse effect of tetracycline
Nausea and vomiting
Tetracycline advserse effects:
Deposition in bones and primary dentition causing DISCOLORATION AND HYPOPLASA
“teethracylcine”
Fanconi syndrome
Hepatotoxicity
Phototoxicity
Vestibular problems
Tetracycline may also cause this syndome
Fanconi’s syndrome nephrocalcinosis
rare renal tubule disorder causing excess amounts of glucose, bicarbonate, phosphates, uric acid, potassium, amino acids
Tetracyclines cause these symptoms
Enamel dysplasia
Inhibition of bone growth affecting epiphyseal plate also Quinolones
Tetracycline causing phototoxicity
Demeclocycline
Tetracycline causing vestibular problems
Minocycline
Only aminoglycoside given for Neisseria
Spectinomycin
Tetracycline with longest half life
and with highest protein binding
Doxycycline
cleared renally and fecally without liver metab
Tetracycline with best absorption and tissue penetration
Minocycline
Tetracycline contraindications:
Pregnant
Children under 8 years
Teratogen and teeth stainer
Covers gram negative: H influenzae, N meningitidis, N gonorrhea, Salmonella typhi, Brucella, Bordetella pertussis
Anaerobic gram positive cocci: C tetani, Mycoplasma
E coli, V. cholerae, Shigella, Chlamydia, Mycoplasma
Not effective against Pseudomonas, Histolytica, Entamoeba
Chloramphenicol
Chloromycetin
Used for tyhpoid fever Bacterial meningitis Anaerobic infections Rickettsial disease (murine, scrub typhus, recrudescent typhus) Rocky Mountain Spotted Fever Q fever Brucellosis
Chloramphenicol
Current DOC for typhoid
Ceftriaxone
Chloramphenicol resistance
Acetylation of chloramphenicol by acetyl-transferase enzyme (acetylated form cannot bind ribosome)
Decreased cellular permeability
Mutation leading to ribosomal insensitivity
Because of potential toxicity, this should only be employed with a well-defined and indicated condition
Acetylation by acetyl transferase - cannot bind ribosome, resistance
Decreased cellular permeability
Chloromycetin
Chloramphenicol
Chloramphenicol AR
Anemia (dose dep) Aplastic anemia (dose INdep) Grey baby syndrome (lack of UDP- Glucoronyl transferase) ashen grey color of skin and lethargic eyes
Most important to toxicity of chloramphenicol is
Hematologic:
Bone marrow aplasia (benzene)
Idiosyncratic (aplastic anemia)
Dose-related reactions: erythroid supression of bone marrow (hypocellular aslo Vinblastin, Vincristine)
Chloramphenicol should not be given with a
phenobarbital (shortens half life)
inhibits protein synthesis at 50s ribosomal subunit
Macrolide
From streptomyces erythreus
Formerly Ilotycin
Alternative to penicillin if with allergy
Mainly for gram positives ineffective for gram neg
Bacteriostatic at low conc
Bactericidal at high conc
Erythromycin
Erythromycin activity
Static in low concentrations
Cidal in high concentrations
Covers Corynebacterium
Chlamydia
CAP (pneumococcus, mycoplasma, legionella)
Staph
Atypicals: Mycoplasma, Legionella
Gram neg: Neisseria, Bordatella
Erythromycin
Allergy with penicillin drug of choice
Erythromycin
Allergy with erythromycin
Vancomycin IV
Allergy with Vancomycin
Aztreonam
Erythromycin base can be inactivated by
gastric acid
Esters of erythromycin base with improved acid stability and absorption less altered by food
stearate
estolate
ethylsuccinate
DOC for Legionnare’s disease Mycoplasma Campylobacter Chlamydial infection Diptheria Pertussis
Also covers for
Gram positives: pneumococci, legionella, chlamydia, listeria, helicobacter, mycobacteria
Gram negatives: neisseria, bordetella, bartonella, rickettsia, campylobacter, H influenzae (less susceptible)
Erythromycin
Macrolides
Adverse effects of erythromycin
Epigastric distress
Cholestatic jaundice (estolate from erythromycin)
GI: anorexia, nausea, vomiting, diarrhea
Hepatitis, fever and rash
Erythromycin causes diarrhea because
it directly stimulates gut motility
IM injection of erythromycin may lead patient to experience
Pain for hours
Deafness (transient)
Erythromycin is an enzyme
Inhibitor of CYP450
Erythromcin increases levels of
Theophylline Oral anticoagulants Cyclosporine Digoxin Statin Corticosteroids Carbamazepine
Unique pharmacokinetic properties
Extensive tissue distribution
High drug concentration in cells (including phagocytes) resulting in greater tissue and secretion concentration compared to serum concentration
Half life of 3 days!
Does not inactivate CYP450
Azithromycin
once a day dosing
should not be given with food
Azithromycin
Used for nongonococcal urethritis caused by chlamydia, LRTI, PID, pharyngitis, Legionnaire
Azithromycin
More active against staph and streph
Used in PUD antimicrobial protocol with omeprazole or lanzoprazole
Given with or without food but extended release form as once a day dosing (with food to improve bioavailability)
Clarithromycin
Inhibits protein synthesis by binding to 50s ribosomal subunit of bacterial ribosome
Exhibits cross resistance with macrolides
Clindamycin
Sulfur-containing antibiotics isolated from Streptomyces lincolnensis
Resemble macrolides in antibacterial spectrum and biochemical mechanism of action but has cross resistance
Inhibits 50s subunit
Lincomycin
Potent agent available for non-spore forming anaerobic bacteria (Bacteroides fragilis)
But best for anaerobes like Bacteroides
Clindamycin
Aspiration pneumoniae
Anaerobics DOC
Clindamycin
Intraabdominal infection DOC
Metronidazole
Covers
Gram positives: streptococci, staphylococci, pneumococci
Anaerobes: Gram positive and Gram negative Bacteroides
No activity against Enterococci, Gram negative aerobic bacteria
Clindamycin
Drug inducing C difficile infection
Clindamycin
Ampicillin/Amoxicillin
Cephalosporin
Fluoroquinolone
Treats anaerobic infection
Penetrating wounds of abdomen and gut
Female genital tract infections
Aspiration pneumonia*
Clindamycin
Clindamycin AE
Diarrhea
Nausea
Skin rash
Pseudomembranous colitis*
Patterned after Nalidixic acid
Quinolones
Introduction of fluorine atom forming fluoroquinolones enhances antibacterial activity
Fluoroquinolone
Most potent fluoroquinolone
Ciprofloxacin
Fluoroquinolone inhibits DNA synthesis due to inhibition of
DNA Gyrase
Topoisomerase II and IV
First Gen Quinilone
Nalidixic acid
Non-fluorinated
Second Gen Quinolone
Ciprofloxacin -most potent fluorinated quinolone
Ofloxacin
Third generation quinolone
Gatifloxacin flourinated
Fluoroquinolone AE
Diarrhea* Nausea* Closure of epiphyseal plates* Headache Dizziness Nephrotoxicity Phototoxicity*
Fluoroquinolone absorption is decreased with
sucralfate
antacid containing aluminum and magnesium
iron and zinc
Antibiotic that can cause seizure
Fluoroquinolone
For UTI Skin Bone Soft tissue Respiratory tract infection Prostatitis STDs Diarrhea due to Campylobacter, salmonella, shigella, e coli
Fluoroquinolone
Fluoroquinolone examples
Ciprofloxacin
Levofloxacin
Norfloxacin
Ofloxacin
Fluoroquinolone SE
Cartilage erosion in children (early closure of epiphyseal plate) * Tendonitis and tendon rupture in adults* Photosensitivity Headache and dizziness Insomnia Diarrhea, nausea
Used as urinary antiseptic
Pregnancy Category B
Contraindicated at term
Nitrofurantoin
Nitrofurantoin should not be given to nursing mothers because
it enters breast milk
discontinue
DOC for Chagas disease
Nifurtimox
Paul Ehrlich’s discovery of the antisyphilitic Salvarsan paved way for the creation of this drug
Sulfonamide
Metabolism of prontosil (bright red dye) in vivo to sulfanilamide (active drug)
Sulfonamide
Structural analog of PABA
Competes with this substrate for enzyme Dihydropteroate synthetase preventing the synthesis of bacterial folic acid
Sulfonamide
Sulfonamide inhibits the enzyme
Pteridine synthetase or
Dihydropteroate synthetase
Trimethoprim inhibits formation of tetrahydrofolic acid by inhibiting the enzyme
Dihydrofolate reductase
Tetrahydrofolic acid is converted to
Thymidine
Purine
Methionine
Methotrexate inhibits the enzyme
dihydrofolate reductase
Sulfonamide inhibits the conversion of
P aminobenzoic acid to Pteridine
Trimethroprim inhibits the conversion of
Via enzyme
Dihydrofolic acid to tetrahydrofolic acid
Dihydrofolate reductase
Essential cofactor for formation of Thymidine, Purines and Methionine
Folic acid
Well absorbed orally
Displaces substances bound to albumin (bilirubin, warfarin)
For gram positive and gram negative Nocardia, Chlamydia, E coli, Klebsiella; Enterobacter
Sulfonamide
UTI sulfonamide
Sulfamethoxsazole
Ulcerative Colitis
Crohn’s
Sulfasalazine
Burn infection
Silver sulfadiazine
Ocular infection
Sulfacetamide
Nocardiosis drug of choice
Sulfisoxazole
Toxoplasmosis
Sulfadiazine with pyrimethamine
Treatment of first attack of urinary tract infection
Co trimoxazole
In burn therapy to prevent and treat bacterial infection
Silver sulfadiazine
Mafenide
Treatment of conjunctivitis
Superficial ocular infections
Sodium sulfacetamide
Treatment of chloroquine resistant malaria
Quinine
Pyrimethamine
Sulfadoxime
Quinine
Pyrimethamine
Sulfadoxime
Fansidar
DOC for pneumocystis carinii
Cotrimoxazole
Alternative drug: Pentamidine
Sulfonamide can
displace substances bound to albumin
Adverse Effects of Sulfonamide
Crystalluria Hematuria Rashes (SJS) Anemia (hemolytic) in patients with G6PD Nausea and vomiting Kernicterus
Sulfonamide is contraindicated in pregnancy because
it crosses placenta and breast milk
Drugs that most commonly cause SJS
Sulfonamide
Aromatic Anticonvulsant
Allopurinol
Mechanism of action is similar to sulfonamide
Sulfones
Used to treat leprosy
Dapsone
Methemoglobinemia
Hemolytic anemia G6PD
Associated with methemoglobinemia and hemolytic anemia G6PD
Competes with PABA to prevent dihydrofolate reducatase
Dapsone
Dihydrofolate reductase inhibitor
Given with sulfamethoxazole
Trimethoprim
DOC for Pneumocystis carinii PCP
Also used in complicated UTI, bacterial prostatitis, gonorrhea, sinusitis, AOM, pneumonia
Also effective in chancroid, shigellosis, tyhphoid fever, Nocardiosis
Trimpethoprim
Trimethoprim SE
Leukopenia
Megaloblastic anemia
Granulocytopenia
Severe hypoxemia in immunocompromised
Pneumocystis carinii
prophylaxis for PCP is given if CD4 count is
<200
Prophylaxis for MAC is given is CD4 is
<50
Drugs CI in G6PD
Sulfonamides
Anti malarials
Drugs that induce SLE
Hydralazine
Isoniazid
Methyldopa
Procainamide
Confer antibiotic resistance
Bacterial plasmids
Cidal = kills
Cell wall synthesis inhibitors
Narrow spectrum
Bactericidal
Static inhibits growth
Protein synthesis inhibitors
Broad spectrum
Bacteriostatic
Cell wall synthesis inhibitors
Penicillin
Cephalosporin
Carbapenem
Monobactam
Aminoglycoside contraindicated in pregnancy:
Streptomycin
Aminoglycoside is CI in patients with
Myesthenia gravis
Tetracycline CI
Pregnant
Children under 8
Erythromycin
Inbibits CYP450
Inc theophylline, digoxin
C difficile drugs
Clindamycin
Ampicillin/Amoxicillin
Cephalosporin
Quinolone
Meningococcemia
First line: rifampicin
Second line: ciprofloxacin
Sulfonamide used to treat malaria
Fansidar (Sulfadoxine + Pyrimethamine)
Sulfonamide SE
Crystalluria hematuria SJS Anemia (hemolytic) in G6PD Nausea and vomiting Kernicterus Crosses placenta and breast milk - contraindicated
Loss of eyebrows, collapsed nasal bridge, aesthetic patches
Erythema nodosum leprosum and multibacillary leprosy
Leprosy
Give rifampin, dapsone, clofazimine