binds 30s slows proof-reading more bacterial membrane permiability OUT by kidney

Antibiotics II Flashcards by O lawformonde

Tetracyclines

Protein Synthesis Inhibitors

DOXYCYCLINE
Tetracycline
Minocycline
Tigecycline

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Aminoglycosides

Protein Synthesis Inhibitors

GENTAMYCIN
TOBRAMYCIN
Amikan
Streptomycin

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Cloramphenicol

category?

(Protein Synthesis Inhibitors)

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Antifolates

DNA Synthesis Inhibitors

SULFAMETHOXAZOLE (SMX)
TRIMETHOPRIM / SMX (Cotrimoxazole)
Dapsone

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Fluoroquinolones

DNA Synthesis Inhibitors

CIPROFLOXACIN
LEVOFLOXACIN
MOXIFLOXACIN
Ofloxacin

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(Urinary Tract Antisceptics)

Nitrofurantoin

Methenamine

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How to initiate protein synthesis?

f-met tRNA = binds initiation factors and 30s + 50s

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Protein synthesis inhibitors - 30s inhibitor

Buy AT 30, CCELL at 50.

Aminoglycosides [-cidal]
Tetracyclines [-static]

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Protein synthesis inhibitors - 50s inhibitor

Buy AT 30, CCELL at 50.

Chloramphenicol, Clinda [-static]
Erythromycin [-static]
Lincomycin [-static]
Linezolid [variable]

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Tetracyclines

[-static}
characteristics

*bacteria selective (no euk)
*binds reversibly to 30S
*blocks binding of amino-tRNA to A site
(can’t add aminos)
*gram +/-

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Tetracyclines

resistance

*efflux (use DOXY, mino, tige)
*30S ribosome protection (use tige)
*Enzymatic inactivation (acetylation)
TIGECYCLINE -no cross resistance

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Doxycycline PO/IV
Minocycline

(Tetracyclines)

low renal clearance

longer t1/2

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Tigecycline IV

Tetracyclines

glycylcycline

* MDR organisms - MRSA, VRE, ESBL

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Doxycycline

Tetracyclines
use

atypical pneumonia
NGU (chlamydia)
Rocky Mtn. Spotted Fever
Lyme Disease

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Tetracyclines

[-static}
ADME

Ca, Mg, Fe, Al, food, divalent metals - down absorption
bones/teeth
Minocycline - CSF
non-renal elimination = Mino/doxy/Tige (SAFEST FOR kidney problems)

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Tetracyclines

[-static}
Toxicities

gut microflora change
superinfection
Mino/doxy - vestibular dysfunction (up CNS penetration)
Outdated - renal tubular acidosis (fanconi syndrome)
grey teeth - no kids under 8 + pregger

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Aminoglycosides

Mnemonic

Mean GNATS can NOT kill anaerobes

amino-, genta/neo/amikan/tobra/strepto
Nephro/oto-toxic, teratogen
need O2 - inner membrane transport

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Aminoglycosides

MOA

binds 30s
slows proof-reading
more bacterial membrane permiability
OUT by kidney

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Aminoglycosides

resistance

**Enzymatic inactivation
Impaired uptake
ribosomal protein mutation (strepto)

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Aminoglycosides

efficacy

*-cidal
*irreversible
*works hours after cleared
*concentration-dependent killing
LOWER TOXICITY - 1x day (larger dose)

Aminoglycoside

Specificity

*Aerobic Gram -ve enteric
(pseudomonas)
*Genta/Tobra - all Gram -, Pseudomonas (more tobra)

Aminoglycosides

synergy

+ B-lactam/vanc
*thinner cell wall, more penetration
+ Pen/Vanc
*wall inhibitor (ALWAYS), more Rx in periplasmic space

Aminoglycosides

ADME

doesn’t cross membrane, stays in plasma (use- sepsis!) + B lactam = up tissue levels
NO ORAL, use iv/im
Tobra - nebulized (Pseudomonas - cystic fibrosis)

Aminoglycosides:

Toxicities

*oto/nephro-toxic
(renal impairment - monitor plasma after 3 doses)
*irreversible
*Vestibular damage

Chloramphenicol MOA

* Binds 50s * stops peptidyltransferase * can affect eukaryotic ribosomes (stop aerobic metabolism)

Chloramphenicol ADME

* Liver metab * Cyp 2C/3A inhibition * caution-infants/alcoholics (bad liver)

Chloramphenicol Toxicities

``` Hematological Effects: • Bone marrow suppression • Aplastic anemia DON'T USE • “Gray Baby Syndrome” • Potential for Drug Interactions: ```

Antifolates (TMP/SMX) block

folate synthesis of Nucleic Acids

SMX targets | Antifolates

PABA , block folate production (bacteria only--mammals have dietary folate) *dihydropteroate synthase

TMP targets | Antifolates

Folate (bacteria + humans) * Dihydrofolate Reductase - bacteria selective - HUGE dose needed for human

Sulfonamides SMX | Antifolates resistance

* Impaired uptake, increased efflux * dihydropteroate synthase mutation * up PABA synthesis

Sulfonamides SMX | Antifolates characteristics

* water insolubule * -static alone, -cidal w/ TMP * for select Gram +/-

Cotrimoxazole (SMX/TMP PO) | Antifolates use

UTI/prostatitis | Otitis/Sinusitis

Dapson | Antifolates Use

leprosy

Sulfonamides SMX | Antifolates ADME

* CNS and CSF (fetus) * Hepatic metabolism * urine excretion (watch renal failure!) * acidic urine - crystalluria (so hydrate patient)

Sulfonamides SMX | Antifolates Adverse Effects

• Hypersensitivity • Hematopoietic Toxicity • urine Crystallization (give with fluids) • bilirubin displacement (bind albumin) NO w/ newborns, pregger - yellow baby, kernicterus

Fluoroquinolones MOA

* stop DNA gyrase | * stop Topoisomerase IV (gram +)

Fluoroquinolones resistance

* DNA gyrase/topoisomerase IV mutation * more efflux * less influx

Fluoroquinolones use against

* Gram +/- | * concentration-dependent killing

Ciprofloxacin | Fluoroquinolones use against

Gram (-) rod * Complicated UTI (no longer 1st line) * Traveler's diarrhea * anthrax

Levafloxacin +Moxifloxacin | Fluoroquinolones use against

Gram (-) rod + cocci * **S. PNEUMONIA * S. aureus (MSSA) * Legionella, chlamydia * **TB * some anaerobes

Fluoroquinolones ADME

* ANTACIDS (Ca, Fe, Mg, Al) - LESS absorption * most URINE * Moxifloxacin - HEPATIC

Fluoroquinolones toxicities

* GI toxicity (nausea, vomiting), dizziness, headache, rash * Cartilage * Tendonitis/rupture * acute psychosis * NO w/ NSAIDS - CNS effects (gaba-a) * QT prolongation (levo/moxi) * NO children, pregnant

Acute uncomplicated Pyelonephritis Rx 1st line

Cipro | TMP/SMX

Urinary Tract Antiseptics characteristics

*poorly absorbed

Nitrofurantoin | Urinary Tract Antiseptics

* UTI * bacterio-selective * MOA - free radical damage * NO preg/baby/renal dx * brown pee

Methenamine (1859) (Urinary Tract Antiseptics)

* less UTI activity than Nitro * need low pH - acidify urine * MOA - make formaldehyde, cross-link to proteins * resistance rare

Acute Uncomplicated Cystitis Rx 1st line

TMP/SMX | Nitrofurantoin