Ocular Antibiotics PDF

Diseases of the eyelids Bacterial blepharitis ○ Most causative agent - S. aureus (S. epidermidis also ID as a cause) ○ Anterior blepharitis: affects the outside of your eye, where your eyelashes attach to your eyelid (Gland of Zeiss associated to follicular with eyelashes) ○ Posterior blepharitis (m...

Diseases of the eyelids Bacterial blepharitis ○ Most causative agent - S. aureus (S. epidermidis also ID as a cause) ○ Anterior blepharitis: affects the outside of your eye, where your eyelashes attach to your eyelid (Gland of Zeiss associated to follicular with eyelashes) ○ Posterior blepharitis (meibomianitis): affects the outside of the inner edge of the eyelid — the part that touches your eye. This type of blepharitis happens when the meibomian glands in eyelids get clogged ○ Agents to treat: usually treated with topical antibiotic Bacitracin (DOC) Prevents formation of polysaccharide chain (bactericidal) Disruption of cell wall synthesis Only available in ointment Gram (+) spectrum; also active against Neisseria but other gram (-) are resistant Commercially only available in topical ointment formulation for ophthalmic use (unstable in solution) Ophthalmic ointments Systemically causes renal necrosis Polysporin (Bacitracin + Polymyxin B), Neosporin (Neomycin + Bacitracin + Polymyxin B) Erythromycin ointment Group of macrolides (inhibit protein synthesis at 50s ribosome subunit) Bacteriostatic BID Staphylococcus, Streptococcus, Mycobacterium, Chlamydia Poor activity against Haemophilus influenza Resistance ○ Alteration in cell membrane permeability ○ Modification of 50s subunit binding site Bacterial angular blepharitis ○ Affects outer canthal area ○ Staph species most common; Moraxella also ID ○ Staph infections respond to classic bacterial blepharitis tx ○ Moraxella infections respond to tx with fluoroquinolone if severe but not usually seen ○ Meibomian Gland Dysfunction ○ Meibomian seborrhea and meibomianitis or meibomitis (aka internal hordeolum) ○ Patients will complain of dry eyes; 2 types of dry eyes (autoimmune disease attacking lacrimal gland or evaporative dry eye) ○ Tx: topically nothing. Lid massage and warm compresses. MG responds to pressure and warmth and works. ○ For some patients is not enough (Doxycycline) reduces inflammation and causes some activation for MG (~40 mg) ○ If internal hordeolum is present, treat bacteria first ○ Meibomian plugging ^ If expressed, clear fluid will come out and that means there is no bacteria It is just an accumulation of lipid ○ If expressed ^, a creamy substance will come out and that means there is some kind of bacterial infection of S. aureus External hordeolum ○ Focal infection of the glands of Zeiss and Moll is most often caused by S. aureus ○ Not directly eyelash but looking at eyelash ○ ○ Agents: Bacitracin ointment Polymyxin B/bacitracin ointment (Polytrim) The polymyxin acts as a “soap”, phospholipids in the cell membrane wash out A cationic surfactant that interacts with the phospholipids of the bacterial cell membrane, thus disrupting its osmotic Very active against gram-negative organisms (i.e., pseudomonas, Haemophilus) Topical adverse reactions are infrequent and mild (SPK, allergic reaction) Internal hordeolum ○ Localized staphylococcal infection of the meibomian glands May be associated with a preexisting blepharitis or meibomianitis Left untreated may result in preseptal or orbital cellulitis ○ Agents: Dicloxacillin (250/500 mg capsules) Penicillinase-resistant penicillin (beta-lactamases) Affects bacterial cell wall synthesis by binding to penicillin-binding protein to inhibit transpeptidation Forms weak cell wall causing lysis (bactericidal action) Also causes the production of autolysins Excretion is urinary, dosage adjustment for those who have compromised kidneys and necessary in patient with low creatinine clearance Adverse effects: cross-sensitivity with cephalosporins and can cause serum sickness (RALF - Rash, Arthralgia, Lymphadenopathy, Fever) Cephalexin 1st generation cephalosporin Bactericidal action Causes a defective peptidoglycan, inhibits cell membrane enzyme (alters permeability), inhibits protein synthesis Excreted in the urine by glomerular filtration and tubular secretion (dosage adjustment) Resistance - beta-lactamase producing strains Adverse effects: ○ Hypersensitivity in the form of rash, urticaria, angioedema, pruritus ○ Nephrotoxicity (patients with kidney disease - stay away**) ○ Pseudomembranous colitis Macrolides (Azithromycin, Erythromycin, Clarithromycin) may be used in case of allergies to PCN or cephalosporin Preseptal cellulitis: either from a sinus infection or trauma ○ ○ ○ Infectious process involving lid structures anterior to the orbital septum Eyelid disease (Staph aureus) URT infections - Hemoph. Influenza (gram -) in children usually poor activity against gram Cephalexin, cefadroxil (1st gen against gram +) Secondary to Haemophilus influenza Amoxicillin with clavulanate (Augmentin) ○ PCN active against gram (+) and gram (-) ○ Affects bacterial cell wall synthesis by binding to penicillin-binding protein to inhibit transpeptidation ○ Forms weak cell wall causing lysis (bactericidal action) ○ Also causes the production of autolysins) ○ Excretion is urinary, dosage adjustment necessary in patient with low creatinine clearance ○ Adverse effects: cross-sensitivity with cephalosporins, serum sickness (RALF) ○ Side effects: (look @ past antibiotic lecture) Secondary to Strep. Species and anaerobes Clindamycin (75, 150, 300 mg) comes in IV or oral ○ Inhibits bacterial protein synthesis by binding to the 50s subunit of the ribosomal complex (bacteriostatic) ○ Activity against gram-positive/negative aerobes and anaerobes ○ Absorption of an oral dose is virtually complete (90%), and not affected by foods ○ Resistance: Alteration in cell membrane permeability Modification of 50s subunit binding site ○ Adverse effects: Abdominal pain, nausea, diarrhea Pseudomembranous colitis (may occur during or after antibacterial treatment) Maculopapular skin rashes, urticaria, pruritis Jaundice Azotemia -> high levels of nitrogen in serum which affects the brain, and kidneys (hemolysis) Spread posterior to orbital septum (orbital cellulitis) Unasyn IV (ampicillin w/ sulbactam), 1.5 and 3.0 g vial ○ PCN active against gram (+) and gram (-) ○ Affects bacterial cell wall synthesis by binding to penicillin-binding protein to inhibit transpeptidation ○ Forms weak cell wall causing lysis (bactericidal action) ○ Also causes the production of autolysins ○ Excretion is urinary, dosage adjustment is necessary in patients with CKD ○ Adverse effects Cross-sensitivity with cephalosporins Diarrhea Rash Pseudomembranous colitis ○ Drug interaction - Probenecid decreases the renal tubular secretion of Unasyn Probenecid was an old drug for gout maintenance If used in combo. w/ antibiotic, competitive excretion (Probenecid will leave system, higher levels of penicillin and overtime can become toxic) Diseases of the conjunctiva Hyperacute bacterial conjunctivitis ○ ○ Ocular EMERGENCY Etiology Neisseria gonorrhea (used to be the most common STD but now it’s chlamydia) Neonates (pregnant women) Sexually active adolescents and young adults Starts unilateral Neisseria meningiditis In children Associated with systemic meningococcal infections Vaccine Bilateral, do not see often Staph. (cluster of gram +), Strep (chain of gram +). Haemophilus (bacilli -), Moraxella (rod shape -) ○ 1st line of therapy: Ceftriaxone (parenteral) Vials 250 mg, 500 mg, 1g 3rd generation cephalosporin DOC- adults (>12) - 1-2 grams in a single admin. Or divide in BID; pediatric ( inferiorly, papillary reaction upper tarsus, SPK inferior, inferior marginal infiltrates/ulcers (sterile) ○ Suspected staph. (IF they recur, MRSA infection then Polytrim is highly preferred) Quixin 0.5%, Zymar 0.3%, Vigamox 0.5%, Besivance 0.6% Latest generation fluoroquinolones 1st line therapy ^ Gram (+) and gram (-) Used QID - used aggressively for 24 hrs and then taper (MIC) ○ Suspected Haemophilus Quixin 0.5%, Zymar 0.3%, Vigamox 0.5% (1st line) Ocuflox 0.3%, Ciloxan 0.3% (1st line) 2nd generation fluoroquinolones Ocuflox is less active against gram (+) Used QID Polytrim (1st line of tx for MRSA infections) ○ Suspected staph / Haemophilus, 2nd line therapy short term Aminoglycosides Bactericidal Binds to 30s subunits leading to altered cell membrane permeability Main activity against gram (-) bacilli and staphylococcus species Neomycin ○ Oldest ○ Oral, topical/ophthalmic, and IM ○ Ineffective against pseudomonas (is the group exception) Gentamycin and Tobramycin ○ As an ophthalmic medication, used to be the broad-spectrum drug of choice in bacterial conjunctivitis and sterile contact lens-related corneal ulcers ○ Corneal toxicity after 1 week of use (preferably do not use Gentamycin) ○ Still used as short-term therapy** ○ Tobramycin comes in combo. w/ dexamethasone (Tobradex): can work for gram + or Ocular adverse effects: ○ Toxic keratitis (decrease cell migration, epithelial erosions) ○ Conjunctival hyperemia, chemosis, follicular reaction ○ Drug-induced autotoxic response Chlamydial conjunctivitis ○ ○ ○ Chlamydia trachomatis - obligate intracellular bacterium with bacterial properties, and like virus depends on host cell for biosynthesis Different serotypes D to K - inclusion conjunctivitis A, B, Ba, C - Trachoma Trachoma Disease of underprivileged population North Africa, India, Middle East, SE Asia, USA, Native Americans in SW Common fly is a vector Usually presentation during childhood Stage I Chronic follicular conjunctivitis > superior conjunctiva Mild superior cornea SPK and pannus (decreased oxygenation…?) Purulent discharge Stage II Papillary reaction obscuring follicular reaction and follicles become mature SEIs and limbal follicles may be present Stage III Follicles on sup. limbus going into Herber pits Usually a sign that it is getting bad, filled with lymphocytes Conjunctival scarring (Arlt’s line) Stage IV Conjunctival scarring and no follicles on upper tarsus Corneal pannus superior ○ Scarring leads to entropion, trichiasis and dry eye ○ ○ ○ Inclusion conjunctivitis Serotypes D-K “Chlamydial infection” - most common sexually transmitted disease in US Results from sexual exposure Usually unilateral First week Hyperemia Follicles/papillae (more follicles) with mucopurulent discharge Small pre-auricular node unilateral ○ Second week Superior corneal keratitis Marginal infiltrates SEI Superficial vascularization on superior cornea leading to pannus ○ ○ Oral treatment options Tetracycline 250 mg (never forget to avoid tetra’s to pregnant women and children*) Doxycycline 100 mg BID (DOC) because of better absorption EES * Azithromycin * *pregnant women and children 12 and under Adjunctive ocular Erythromycin/Tetracycline ung TID Aza Site QID an option (systemically not as good) Diseases of the cornea Bacterial keratitis (Ulcer) & Sterile keratitis (peripheral, not as much pain) ○ More common etiologies Staphylococcus 14-33% cases in cl Streptococcus Pseudomonas 62-64% of ulcers in cl (can damage cornea in 24 hrs) ○ Symptoms (more central) Pain Redness Pt describes a “white dot” in cornea Photophobia Discharge Decreased vision ○ Infectious ulcer vs. sterile ○ Location Size of epithelial defect Hyperemia A/C reaction (hypopyon) Signs Vary according to severity and organism Strep. Pneumoniae - gray-yellow, disc-shaped ulcer, and hypopyon is characteristic Staph. Penumoniae - well-defined white-gray or creamy stromal infiltrate that may enlarge to form a dense stromal abscess; uveitis and hypopyon less common than in strep Pseudomonas aeruginosa (G (-) rods) - central with a gray infiltrate and overlying epithelial defect which progresses very rapidly and a ring ulcer can develop; can cause corneal perforation within 24-48 hours ○ Anti-infective options Moderate risk (1-1.5 mm, peripheral or mid-peripheral, A/C reaction and discharge) Fluoroquinolones - Ciprofloxacin (Ciloxan 0.3%), Ofloxaxin (Ocuflox 0.3%), Levofloxacin (Quixin 0.5%, Iquix 1.5%)**; Gatifloxacin (Zymar 0.3%)*; Moxifloxacin (Vigamox 0.5%)* ** FDA approved *better for gram (+) High risk (1-1.5 mm, peripheral or mid-peripheral, A/C reaction and discharge) Require addition of fortified antibiotics - fortified gentamycin or tobramycin (15-40 mg/ml) alternated w/ fortified cefazolin (50 mg/ml) or vancomycin (24 mg/ml; MRSA) every 60 min Oral fluoroquinolones are (Avelox 400 mg, Cipro 500 mg, or Levoquin 500 mg) are given when ulcer involves extremely deep ulcerations In occasions pt’s are hospitalized for IV administration Recurrent corneal erosions (not infectious processes) ○ Any damage to EBM or Bowmans will result in weak adhesions between epithelium and anterior stroma Basal cells adhere epithelium to stroma by secreting the basement membrane Hemidesmosomes attach BM to rest of epithelium and anchoring fibrils to anterior stroma Defective basement membrane = RCE Hemidesmosomes of the basal layer fail to adhere to the basement membrane (deficient attachment) Corneal epithelium remains loose with a slight subepithelial edema Loose epithelial layers are susceptible to separation and erosion Can take up to 4 days to heal but if recurrent, can come up ~5-6x a year ○ Causes - past injury, dystrophy ○ Symptoms - recurrent pain attacks and photophobia upon awakening or during sleep when the eyelids are rubbed or opened ○ Signs Positive/negative NaFl staining Antibiotic treatment Doxycycline Upon injury, leukocytes secrete metalloproteinases which degrade damaged BM and anchoring system In RCE, abnormally high levels of metalloproteinases persist Doxycycline inhibits metalloproteinases Acquired dacryocystitis ○ Common bacteriological agents Most common is Staph Others: Streptococcus, Pseudomonas, and Haemophilus in child ○ Symptoms Epiphora (excess watering), pain, fever ○ Signs Swelling over sac, mucoid or purulent discharge when pressure over sac ○ Treatment options Children No fever and mild ○ Augmentin ○ Alternative tx.: Cefixime (Suprax) or Cefaclor Fever and moderate-severe ○ Hospitalize w/ cefuroxime Allergy ○ Erythromycin, Azithromycin, Clindamycin Adults No fever and mild ○ Cephalexin ○ Alternate tx.: Augmentin Fever and ill ○ Hospitalize Cefazolin IV Allergy ○ Zithromax, Fluoroquinolones Adjunctive topical - Polytrim QID Reactive toxoplasmosis ○ Toxoplasmosis gondii ○ Localized roughening of epithelium ○ Single-cell obligate, intracellular protozoan parasite Oocyst (dormant form) and tachyzoites (active form) Cats primary host Transmission by ingestion of under-cooked mear and transplacental (severity related to stage of pregnancy) Frequent reactivity common in HIV patients Signs (active) Creamy, white, focal chorioretinal lesions Vitritis and iridocyclitis protozoan parasite Recurrent lesions tend to occur at the border of old chorioretinal lesions ○ Active agents Pyrimethamine and trimethoprim (not a synergistic medication, use Sulfa for synergistic activity) MOA: interferes with intermediary metabolism of folic acid by binding and blocking the activity of dihydrofolate reductase Pyrimethamine (DOC) especially active at this site and produces a synergistic action in used in combination with sulfas (e.g, Sulfadiazine) Bacterial endophthalmitis ○ Relatively uncommon ○ ○ ○ ○ ○ Related to intraocular surgery (poor aseptic/sterile technique) Staph. Aureus and epidermidis most common Signs and symptoms Sudden VAL Pain Severe episcleral and conjunctival inflammation Severe anterior and posterior segment intraocular inflammation Hypopyon Agents Vancomycin Inhibit bacterial cell wall synthesis Active against staph, strep, clostridium (oral), and Neisseria In ocular surface infections only reserved for severe cases in which less toxic agents have been ineffective Great activity against MRSA and MRSE DOC for staph. Endophthalmitis - 0.25% intravitreal concentration Prolonged oral use may cause ototoxicity and nephrotoxicity High allergic potential, contraindicated in patients with known hypersensitivity to the drug, also in cases of hearing loss and severe renal impairment Amikacin Aminoglycoside Very active against gram-negative bacilli Chemical modification present makes it tolerant to many aminoglycoside-inactivating enzymes Primary agent along with Vancomycin for the treatment of bacterial endophthalmitis Ototoxicity, nephrotoxicity and neuromuscular blockage Contraindicated in patients with of hearing loss, severe renal impairment, and neuro-muscular disease