Ocular infection & inflammation pharmacology Flashcards

1
Q

Infection considerations

A
  • barriers (skin & mucous membranes)
  • Immune status
  • organisms (bacteria, virus, fungi)
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2
Q

Gram positive Cocci

A
  • staph aureus
  • staph epidermidis
  • strep pneumonia
  • strep pyogenes
  • strep faecalis
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3
Q

Gram negative Rods

A
  • Haem Influenzae
  • Pseudomonas aeruginosa
  • Serratia Marcescens
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4
Q

Gram negative Cocci

A
  • Neisseria gonorrhoeae
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5
Q

Bacteria def

A
  • single celled

- subdivided by shape and gram stain

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6
Q

Gram Stain

A
  • pos = violet = thick peptidoglycan layer in cell wall

- neg = red = thinner petidoglycan layer

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7
Q

unique structural bacteria

A
  • Rickettsia (gram - found in ticks, fleas & mammals)(zoonotic)
  • Chlamydia (mimic virus)
  • Treponema palladium (syphilis - the masqarader)
  • Mycobaterium tuberculosos
  • Actinomyces (anaerobic - resemble fungal hyphae)
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8
Q

Bact uniqueness

A
  • Peptidoglycan Cell wall (penicillin vulnerability)

- Ribosome cell membrane

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9
Q

Bactericidal

A
  • destroys cell wall - peptidoglycan - Penicillin
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10
Q

Bacteriostatic

A
  • inhibit cell growth - Tetracycline
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11
Q

Selective toxicity

Bact vs human

A
  • Bact has cell walls - antibacterial inhibits synthesis of cell wall
  • Cell membranes are similar
  • Ribosomes - diff size and composition
    • inhibit bact protein synthesis
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12
Q

Selective toxicity

Drugs

A
  • biosynthetic pathways (intermediary metabolism)(Folic acid - bact produce/synthesize)
  • Enzyme DNA gyrasee (prevents supercoiling of DNA during replication & transcription)
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13
Q

Mechanisms of Resistance

A
  • Bact produces enzymes that degrade/inactivate antibiotics
  • pump mechanisms (pump out) or decrease permeability of antibiotics
  • resistance genes
  • alteration for bact ribosomes
  • chromosomal mutation
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14
Q

Cross resistance

A
  • Misuse/overuse/non-compliance - SYSTEMIC mostly
  • excess from animal feed
  • leads to resistance to similar groups of antibiotics
  • penicillin vs cephalosporins (similar drug structure)
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15
Q

Indications for oral antibiotics

A
  • Meibomianitis
  • Internal Hordeolum
  • Ocular Rosacea
  • Dacryocystitis
  • Preseptal Cellulitis
  • Chlamydial Conj
  • Prophylaxis (fractures, sinusitis)
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16
Q

Topical Anti-biotics Use

A
  • Ant Segment infection
  • Conjunctivitis
  • Corneal Ulcer
  • Blepharitis
  • Prophylaxis
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17
Q

Drug considerations

A
  • selective toxicity
  • spectrum of activity (narrow vs broad)
  • resistance
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18
Q

Guideline for effective therapy

A
  • accurate dx
  • microorganism sensitivity to anti-infective
  • least toxic drug
  • adequate drug level
  • optimum route of admin
  • appropriate dosage
  • appropriate tx time
  • augment with physical procedures
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19
Q

Antimicrobial Failure - why?

A
  • inaccurate Dx
  • resistance (drug)
  • inadequate dosage
  • noncompliance
  • inadequate suppl physical procedures
  • inadequate immune system response
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20
Q

Drugs affecting Cell Wall

A
  • Penicillins
  • Cephalosporin
  • Vancomycin
  • Bacitracin (ung)
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21
Q

Vancomycin

A

-think = last line for MERSA

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22
Q

Chloramphenicol

A
  • think = aplastic anemia
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23
Q

Penicillins

A
  • Augmentin (Amoxicillin + clavulanate)

- Dicloxacillin

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24
Q

Cephalosporins

A
  • Cephalexin (Keflex)

- Cefaclor (Ceclor)

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25
Q

B-Lactam antibiotics

A
  • Penicillins & Cephalosporins
  • B-lactam ring (similarity)
  • resistant bact produces enzyme to disrupt B-lactam ring
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26
Q

Penicillins use

systemic

A
  • Hordeolum
  • Preseptal cellulitis
  • Dacryocystitis
  • Dacryoadenitis
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27
Q

Penicillin adverse reaction

A
  • Hypersensitivity response (type 1 - 4) (2%)
  • GI irritation (nausea, vomit, diarrhea)
  • diarrhea is common - kills normal flora
  • Superinfection (Tx but gets worse)
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28
Q

Penicillin vs Cephalosporin

A
  • if Penicillin hypersensitive less than 2% cross-react to cephalosporin
  • less likely in 3rd + 4th gen Cepalos
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29
Q
clavulanate mechanism 
(Augmentin)
A
  • B-Lactamase inhibitor
  • protects penicillin from penicillanse
  • weak anti-microbial activity
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30
Q

Cephalosporins

A
  • B-lactam ring (similar to Penicillin)
  • addition of acyl side chains (1-4 gen)
  • Broad spectrum
  • Bactericidal
  • Resistance (B-lactamase)
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31
Q

Cephalosporin Use

A
  • same as Penicillins

- other (ophthalmically fortified use)

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32
Q

Bacitracin

A
  • Gram +
  • Bactericidal
  • Ointment (unstable in sol)
  • Combo = Polycin (Bacitracin + Polymyxin B)(for Gram - )
  • Blepharitis
  • Dose - QD > TID
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33
Q

Vancomycin

cell wall destroyer

A
  • highly active for gram +
  • Bactericidal
  • Dosage - Sol-inject, capsule, powder for fort
  • Highly toxic - anaphylaxis, vasculitis, nephrotoxic, ototoxic (delayed), neutropenia, more
34
Q

Vancomycin use

A
  • Bact endopthalmitis
  • Methicilin/Penicillin resistant infections
  • Bact Keratitis - vision threat
  • Ruptured globe
  • Orbital cellulites
35
Q

Cytoplasmic Membrane affectors

A
  • Polymyxin B
  • Gramicidin
  • disrupts cell membrane permeability
36
Q

Polymyxin B

A
  • disrupts cell osmotic integrity
  • bactericidal
  • Gram - (pseudomonas)
  • ## use - conj & lid infects
37
Q

Polymyxin B combos

A
  • Polymyxin B/Neomycin/Gramcidin (generic)
    -Polymyxin B/Trimethoprim (Polytrim)
  • Polymyxin B/Bacitracin (Polycin)
  • Polymyxin B/Bacitracin/Neomycin (Neo-Polycin)
    with Steroids:
    Polymyxin B/bacitracin/neomycin/hydrocortison (generic)
38
Q

Gramicidin

A
  • Bactericidal (with static act)
  • Gram +
  • Combo = Neosporin
    Polymyxin B/Neomycin/Gramicidin
39
Q

AntiBact affecting Protein Synthesis

A
  • Aminoglycosides
  • Macrolides
  • Tetracyclines
  • Chloramphenicol
  • Clindamycin
40
Q

Aminoglycosides

Ocular - mostly topical

A
  • Neomycin
  • Gentamicin
  • Tobramycin
  • Amikacin
  • inhibit bact protein synthesis by binding to ribosome (30s subunit)
  • bactericidal
  • gram + & -
41
Q

Macrolides

A
  • Erythromycin
  • Azithromycin (chlamydia*)
  • Clarithromycin
42
Q

Tetracyclines

A
  • Tetracycline
  • Doxycycline
  • Minocycline
43
Q

Neomycin

A
  • Broadspectrum gram +& -
  • ineffective against P.aeruginosa
  • Combo’s
  • ADR = contact dermatitis
44
Q

Gentamicin

A
  • broad spect - better with P.Aeruginosa
  • not effective Streptococcus
  • Use - Ant seg infections
  • ADR - cornea & conj tox & allergy (less than neomycin)
  • Dose - sol/ung - q4h
45
Q

Tobramycin (best choice)

A
  • broad spec c Pseudomonas
  • similar to Gentamicin except:
  • sensitive to gentamicin resistant pseudomonas strains
  • more potent with P. aeruginosa
  • Use - ant seg inf
  • Combo with dexamethasone (Tobradex)(HSV worse!)
  • ADR’s - less than other Aminoglycosides
46
Q

Tetracyclines

also anti-inflam effects!

A
  • Block protein synthesis & bacteriostatic
  • Broad spec +&- & chlamydia
  • S.aureus resistance
  • short, intermediate, long acting
  • topical = Trachoma
47
Q

Tetracycline Oral use

A
  • Chlamydia (inclusion conj + trachoma)
  • Acne rosacea, Meibomianitis
  • Nontuberculous phlyctenular keratoconjunctivitis
  • noninfected corneal ulcers (relates to anticollagenolytic action or oral tetra)
48
Q

lateral canthus bubbles (sign)

A
  • sign of free fatty acids
  • bact in sebum
  • bact releasing lipases increase free fatty acids
  • irritation & inflammation
  • Meibomianitis!
49
Q

Tetracycline Topical use

A
  • gonococcal ophthalmia neonatum (prophylaxis)

- trachoma

50
Q

Tetracycline (class) considerations

A
  • absorption affected by:
    • food (not doxy)
    • iron containing tonics
    • antacids containing Ca, Mg or Alu
    • Sodium Bicarbonate
  • when use restrict:
    Antacids, iron, zinc, dairy, vit/mineral preps
51
Q

Tetracyclines ADR’s

A
  • Hypersensitivity reactions
  • Anaphylaxis, urticaria, rash, periorbital edema
  • Photosensitivity/photo toxic
  • GI irritation (better with food but reduced absorption)
  • Epigastric distress (sore throat/ glossitis
  • tooth development (staining, caries, dysgensis & discolor)(under 8 yrs)
  • depress bone growth (attracted to embryonic & bone growing tissue)
  • pseudotumor cerebri !! watch teenagers!!
  • blood dyscrasias (watch blood thinners-coumadin)
  • vestibular toxicity (minocycline)(tinnitus, dizzy)
52
Q

Tetracycline Contra

A
  • pregnancy (CatD)
  • okay short term during breast feeding
  • no kids under 8 yrs
53
Q

Tetracycline (generic) Uses

A
  • Chlamydia
  • Acne Rosacea
  • Meibomianitis
  • Resistant sebaceous blepharitis
  • accumulate in Sebaceous Glands
  • resistance can be a problem
54
Q

Doxycycline uses

A
  • best choice for Chlamydia/acne rosacea
  • Meibomianitis
  • Ocular surface inflammatory disease
55
Q

Tetracyline Ophthalmic

A
  • not used in US

- replaced by erytrhomycin ophth ung

56
Q

Doxycycline dosage

A
  • 100mg BID (1-2 wks then taper), maintenance PRN (20-100mg daily or less)
  • Oracea (imm & sustained release) = 40mg QD am’s empty tummy
57
Q

Macrolides Pharmacology

A
  • binds to 50S ribosomal subunit - inhibits protein synthesis
  • low toxicity
  • Bacteriostatic
  • spectrum can include:
  • gram - & +
  • streptococci
  • staphylococci
  • Chlamydia
  • Neiserria
  • H influenzae
58
Q

Macrolides clinical use

A
  • chlamydial infections

- sebaceous gland dysfunction

59
Q

Erythromycin

A
  • oral & topical
  • Cat B - safer for pregnant, nursing & kids under 8
  • ung only
  • ADR’s = mild
  • Uses:
  • lid infection
  • prophyl ophth neonatorum
  • Gonococcal conj
  • Chlamydial inf
60
Q

Azithromycin (Zithromax)
Oral - single dose 1000mg
Extended half life > QD

A
  • semisynthetic derivate of erythro
  • Cat B
  • ADR - skin rash/GI upset
  • Uses:
  • Chlamydia
  • gono conj
  • ocular rosacea
61
Q

Azithromycin 1% Ophthalmic

AzaSite

A
  • Durasite-vehicle
  • Growing resistance
  • useful for trachoma not chlamydia
62
Q

anti-inflammatory efffect of anti-biotics

A
  • anti-inflammatory effect helps control bacterial colonization and lid inflammation
  • Doxy treats MGD via antimicrobial, anti-inflamm and antimetalloproteinase prop
  • Azithro inhibits pro-inflamm cytokines
  • 5 day oral Azithro was better than doxy for MGD - better signs, shorter tx
63
Q

Trachoma

A
Oral
- Azithromycin drug of choice
  *children 20mg/kg single dose
  * adult 1g single dose
- Erythormycin = Alt Tx
  * children 30-50mg/Kg/day Q6H x 7days
   * adult 250mg q6h x 2wks
Doxy = Alt Tx
100mg BID x 3 wks

Topical
Tetra or erythro ung BID-QID x 3-6wks
Cochrane favours oral Azithro to topical Tetra

64
Q

Chloramphenicol

A
  • binds to 50s ribosomal subunit
  • Bacteriostatic (some bactericidal act)
  • broad spectrum (P.Aer resistant)
  • Chlamydia
  • Bacillus anthracis - anthrax (systemic)
  • systemic risk for APLASTIC ANEMIA (watch infants on topical) - not dose dependent
  • Avail topical, oral, IV or IM
65
Q

Antibacterials Affecting Folic Acid

A
  • Sulfonamides
  • Pyrimethamine
  • Trimethoprim
66
Q

Sulfonamides

A
  • Broad spectrum
  • also Chlamydia & Toxoplasma (great systemic)
  • Resistance: Staph & Pseudomonas
  • Mainly used orally - Topically too much resistance
  • Inactivated by PABA (local anesthetics - procaine, teracaine - esters of PABA
  • Inhibited by blood, pus - purulent exudates contain PABA
  • Bacteriostatic
67
Q

Topical Sulfonamide - Sulfacetamide (Bleph10)

A
  • sol or ung
  • broad spec
  • resistance++ not useful : (
68
Q

Trimethoprim

A
  • Use - surface ocular infection
  • typical combo with Polymixin B (Polytrim)
  • gram +&- (not pseudomonas)
  • approved for infants 2mths and older
  • ADR’s mild
  • great for kids
69
Q

Antibiotics affect DNA synthesis - Fluoroquinolones

A
  • interferes with DNA synthesis during replication
  • inhibits DNA gyrase - inability to unwind DNA helix for replication
  • results in cell death and ability to replicate
  • resistance is forming
70
Q

Fluoroquinolones Topical Uses

A
  • conj
  • Keratitis
  • Corneal ulcer
  • pre/post Sx
71
Q

Fluoroquinolones Systemic Uses

A
  • UTI
  • GI
  • Respiratory & skin infections
72
Q

Fluoroquinolones resistance

A
  • reduced cellular accumulation - decrease passive transport into cell & Efflux pumps
  • Single step mutation - bact alter DNA gyrase
  • Ciprofloxacin - 10% resistant S. pneumo
  • increasing MRRSA
73
Q

Fluoroquinolones family

A
  • Norfloxacin
  • Ofloxacin
  • Ciprofloxacin
  • Levofloxacin
  • Gatifloxacin
  • Moxifloxacin
  • Besifloxacin (ocular only)
74
Q

Fluoroquinolones systemic ADR’s

A
Common
- GI upset
- CNS (HA & dizzy)
Uncommon
- tendon rupture
- prolongation of QT interval
- Arthroplasty
- hepatitis
- POSSIBLE RD's
75
Q

2nd gen Fluoroquinolones

A
  • Nor, Cipro, Oflox
  • better activity to common paths than:
  • Aminoglycosides
  • Chloramphenicol
  • Tetracycline
  • Erythromycin
  • coneal precipitates with Cipro - goes away with discont
76
Q

3rd gen Fluoroquinolones

A
  • maintained excellent gram- cover with improved gram+ cover
  • less resistance
  • ineffective if cipro/oflox resistance
  • levoflox 0.5% & 1.5%
  • superior to 2nd gen esp Streptococcus
77
Q

4th gen Fluoroquinolones

A
  • 2 mutations required for resistence
  • Gati 0.3%/0.5%
  • Moxi 0.5%
  • Besi 0.6%
78
Q

Moxifloxacin 0.5%

A
  • bact conj
  • no preservative
  • peds use (4mths +)
  • xanthum gum vehicle (better staying power)
  • Cat C
  • Dose 1 gtt BID x 7days
79
Q

Gatifloxacin 0.5%

A
  • bact conj

- Q2H day 1; BID - QID day 2-7

80
Q

Besifloxacin 0.6%

A
  • bact conj
  • SUSPENSION
  • DuraSite delivery system
  • broad spectrum
  • Cat C
  • 1yr old +
81
Q

Considerations for Oral Antibiotics

A
  • Probiotics add in
  • food = yoghurt, sauerkraut, kimchi
  • do not take with anti - after
  • caution px on chemo/compromised immune & proton inhibitors
82
Q

Antibiotics and contraceptives

A
  • possible but not proven
  • 13 fold risk - enzyme-inducing drugs - carbazapine, topiramate, rifampicin
  • 7 fold risk in antibiotics general