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52 Cards in this Set
- Front
- Back
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Penicillin (Beta-lactam)
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-antibacterial drug-> Inhibit cell wall synthesis
-Effective against gram +ve -Acquired resistance (drug deactivating enzymes produced by bacteria) -Allergic reaction problem -Alter normal microflora of body -25+ types (pneumonia, STDs, meningitis, tissue infections, UTIs, Bronchitis, Pharyngitis -CAUTION OF HYPERSENSITIVITY REACTIONS-> CROSS SENSITIVITY |
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Cephalosporins (Beta-lactam)
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-antibacterial drug-> Inhibit cell wall synthesis
-Similar structure to penicillins (action and resistance) -Good against gram +ve bacteria, modest against gram –ve -Broad spectrum, bactericidal, poor oral activity-> IV -First, second, third generation compounds -Septicaemia, pneumonia, meningitis, UTI, Sinusitis |
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Beta-Lactam (penicillin and cephalosporin) Action
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Interferes with cross-linking of peptide chain (final step in bacterial cell wall formation)
Peptide chains give cells wall strength |
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Polymixin B
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-Antibacterial drug-> affects cell membrane
-Cationic surfactant that interacts with cell membranes, increases permeability and causes cell leakage -Effective against some gram –ve bacteria, some pseudomonas strains -Popular for Tx of infections of the conjunctiva and lids Risks: Neurotoxicity, nephrotoxicity |
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Gramicidin
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-Antibacterial drug-> affects cell membrane
-Ineffective against gram –ve bacteria |
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Propamidine (Brolene)
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-Action: Divalent cationic surfactant, affects cell membranes
-Activity: Active against Stap aureus, Streptococcus pyogenes, not active against Pseudomonas, some antifungal properties, action not inhibited by pus -Use: Minor conjunctivitis blepharitis, acanthamoeba -Adverse: Sensitization -Pack: Eye drops 0.1%, 10mL bottle, ointment -Dose: 2-3 times daily for ~1 week -Available over the counter without Rx, S2 |
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Drugs Affecting Intermediate Metabolism Action
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Synthesis of folic acid in bacterial cells only (not human)
-Folate required for DNA synthesis -> humans obtain from diet -Sulfonamides inhibit folic acid synthesis-> contains sulfanilamide -> competes with p- aminobenzoic acid (PABA) for the enzyme involved in folate synthesis (diagram in notes) |
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Sulfacetamide (Bleph-10 Allergan)
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-Action: Sulfonamide, bacteriostatic
-Use: Conjunctivitis, trachoma, generally replaced by other agents, superseded -Adverse: Allergic reactions common -Pack: eye drops 10%, 15mL bottle -Dose: every 2-3 hours during the day for ~1 week -Available OTC -S3, ask about sulphur allergies -Irritant, avoid |
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Drugs Affecting Bacterial Protein Synthesis Action
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-Takes place in ribosomes, differ eukaryotes and prokaryotes, sub-units in bacterial cells are 30S and 50S, human cells are 40S and 60S
-Some can interact with human mitochondrial ribosomes causing group toxic effects |
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Chloramphenical (Chloromycetin, Clorsig)
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-Antibacterial drug-> affects bacterial protein synthesis
-Bind to 50S -Action: Broad Spectrum (corynebacterium, E.coli, Haemophilus, streptoccoi), not effective against Pseudomonas, low toxicity (limits use), binds to bacterial ribosomes, inhibits protein synthesis -Use: Prescribed for topical therapy, effective against gram +ve and –ve bacteria, chlamydia, mycoplasma, rickettsia and spirochetes, rarely used systemically (< resistance) -Adverse: Toxicity, Anaemia, Optic neuropathy, bone marrow depression, fear of possible aplastic anaemia (may be fatal) limits use in some countries (USA), low systemic absorption, gray baby syndrome (child inability to excrete drug⇒ only in inappropriate dosing) -Pack: eye drops 0.5%, 10mL bottle, fridge minims, 20 per box ointment 1%, 4g -Dose: eye dorps 1-2 drops every 2-6 hrs for 2-3 days then reduce frequency -S3, PBS |
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Tetracyclines (Optycin, Latycin)
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-Antibacterial drug-> affects bacterial protein synthesis
-Bind to 30S -Action: Broadest spectrum (gram +ve and –ve), bacteriostatic, resistance develops slowly, not effective against pseudomonas, poor corneal penetration -Use: Ocular infections, chlamydial infection -Adverse: Few side-effects topically, local reactions in isolated cases, oral tetracyclines can permanently yellow teeth and slow bone growth in children -Pack: ointment 1%, 5g now compound pharmacy product (largely superseded by oral azithromycin for trachoma) -Dose: Apply into lower conjunctival sac every 2 hrs, treatment duration depends on severity of condition |
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Macrolides
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-Antibacterial drug-> affects bacterial protein synthesis
-Alternative to penicillins, similar effect -Treat pneumonia, genital infections, legionnaires disease, chlamydial infections -Resistant organisms -Ear damage, GI disturbance -Azithromycin, Erythromycin |
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Azithromycin
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-Antibacterial drug-> affects bacterial protein synthesis
-Bind to 50S -Action: Broad spectrum macrolid antibiotic with anti-inflammatory properties, inhibits protein synthesis, inhibits macrophage activity -Use: Ocular infections, chlamydial infections, toxoplasma, STDs, malaria, respiratory infections -Adverse: GI, HA, bitter taste, hypersensitivity -Pack: 1.5% drops, compound pharmacy product (superseded by azithromycin) -Dose: apply daily, treatment duration depends on severity of infection, long half life (68hrs)⇒ one high oral dose Tx, Oral 1g for adults, 20mg/kg for children |
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Erythromycin
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-Antibacterial drug-> affects bacterial protein synthesis
-Bind to 50S |
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Aminoglycosides Action and Examples
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-Antibacterial drug-> affects bacterial protein synthesis
-Bind to 30S unit of bacterial ribosome preventing protein synthesis -Active against aerobic gram –ve and some gram +ve bacteria -Rapid action, bacrtericidal -If oral can cause nephrotoxicity (kidney damage) and otoxicity (ear damage) -Not for systemic use -Streptomycin, Framycetin, Gentamicin, Neomycin, Tobramycin |
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Framycetin
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-Antibacterial drug-> affects bacterial protein synthesis
-Aminoglycoside -Action: Isomer of neomycin, broad spectrum effective against gram-positive and –negative bacteria -Use: Conjunctivitis, blepharitis, abrasions, styes, topical application, poor ocular penetrance -Adverse: Kidney, ears affected, contact allergies -Pack: eye drops 0.5%, 8mL bottle -Dose: eye drops 2 drops every 1-2 hours decreasing to 3/times per day |
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Gentamicin
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-Antibacterial drug-> affects bacterial protein synthesis
-Aminoglycoside -Action: Broad Spectrum antibiotic, some resistant gram-positive organisms, bactericidal, poor ocular penetration when applied topically -Use: Treatment of external eye and adnexal infection (bacterial conjunctivitis), prophylaxis following surgery or trauma (abrasions), suspected pseudomonas -Adverse: Transient irritation, damage ears, kidneys, sensitisation reduced -Pack: 0.3% 5mL bottle & minums -Dose: 1-2 drops q4h, if severe 2 drops hourly -1.3% fortified for bacterial keratitis |
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Neomycin
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-Antibacterial drug-> affects bacterial protein synthesis
-Aminoglycoside -Action: Broad spectrum antibiotic, some resistance from gram-positive organisms, bactericidal, not effective against pseudomonas -Use: Bacterial infection, rarely used systemically, used prophylactically with steroid after surgery or for inflammation cover -Adverse: ears, kidneys affected, hypersensitivity -Pack: 0.5% minims, Neosporin drops, ointment, compound product |
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Tobramycin
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-Antibacterial drug-> affects bacterial protein synthesis
-Aminoglycoside -Action: Broad Spectrum, some resitance from gram +ve organisms, bactericidal -Use: Treatment of external eye and adnexal infection (bacterial conjunctivitis), prophylaxis following ocular surgery or surface trauma, suspected pseudomonas -Adverse: Ocular and systemic toxicity, superinfection ⇒ retarded corneal wound healing -Pack: eye drops 0.3%, 5mL bottle ointment 0.3%, 3.5g -Dose: eye drops 1-2 drops every 4 hours -Severe infection: 2 drops hourly until improvement -1.3% fortified for bacterial keratitis |
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Drugs Affecting Bacterial DNA Synthesis
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-New generation quinolones and fluorinated quinolones (fluoroquinolones)
-Broad Spectrum, little resistance -Use only for microbial keratitis, extremely severe conjunctivitis -Active against Pseudomonas & Staphylococcus -Cause: Kidney stones, headache, nausea -Not for use in children under 8yrs (cartilage damage) |
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Fluoroquinolones
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-Antibacterial drug-> affects bacterial DNA synthesis
-Newest group, major area for new drugs -Inhibit DNA synthesis during bacterial replication, unique mechanism means cross-resistance with other antibiotics less likely -Well absorbed orally -Inhibit DNA-gyrase, preventing supercoiling of DNA molecule -Ciprofloxacin, Ofloxacin |
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Ciprofloxacin (Ciloxan, Ciloquin)
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-Antibacterial drug-> affects bacterial DNA synthesis
-Action: Active against broad spectrum of gram+ve and –ve ocular pathogens -Use: Bacterial keratitis, severe bacterial conjunctivitis, effective, safe, limit use to prevent resistance -Adverse: Super infection, discomfort, burning, itching, hyperaemia, precipitates on corneal ulcers -Pack: 0.3% 5mL bottle -Dose: -Corneal Ulcers= day 1: 2 drops every 15min for 6 hours then every 30min, Day 2: 2 drops every hour, Days 3-14: 2 drops every 4 hours -Bacterial Conjunctivitis = Days 1-2: 1 drop every 2 hrs while awake, days 3-7: 1 drop every 4hrs while awake |
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Ofloxacin (Ocuflox)
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-Antibacterial drug-> affects bacterial DNA synthesis
-Action: Active against broad spectrum of gram+ve and –ve ocular pathogens -Use: Bacterial keratitis, severe bacterial conjunctivitis -Adverse: Super infection, transient eye pain, hyperaemia, risk of corneal perforation -Pack: 0.3% 5mL bottle -Dose: -Bacterial conjunctivitis= Days 1-2: 1 drop every 4hrs while awake, Days 3-10: 1 drop every 6hrs -Corneal Ulcers= Day 1: 2 drops every 15min for 6hrs then every 30min, Day 2: 2 drops every hour, Days 3-14: 2 drops every 4hrs |
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Antibacterial use for:
BACTERIAL CONJUNCTIVITIS |
-Resolves in 10-14 days
-Staphylococcus aureus, staph. Epidermidis, Streptococcus pneumonia, hemophilus influenza -Microbiological investigations (swabs) rarely needed -Hygiene -Topical antibiotics shorten course -Broad spectrum antibiotic (gram+ive and –ve) -4 times/day for 1 week |
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Antibacterial use for:
BACTERIAL KERATITIS |
-Sight threatening
-CL wear and pseudomonas -Microbial work up -Broad spectrum antibiotic (immediately) -Monotherapy with fluoroquinolone or dual therapy with fortified cephalosporin and aminoglycoside -Drops hourly -Ineffective corneal ulcers: Day1: 2 drops every 15min for 6hrs, then 30min, Day 2: 2 drops every hr, Days 3-14: 2 drops every 4hrs |
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Antibacterial use for:
CORNEAL ABRASION |
-Heals spontaneously within few days
-Ice packs and oral analgesics for pain -Subepithelial lesions referred immediately -Broad-spectrum topical antibiotic used 4 times per day until epithelial healing |
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Antibacterial use for:
ANTERIOR BLEPHARITIS |
-Anterior eye lid margin
-Chronic recurrent nature -Lid hygiene, tear supplements -Weak corticosteroids and antibiotics (chloramphenicol, erythromycin, gentamicin) ⇒ short term |
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Antibacterial use for:
POSTERIOR BLEPHARITIS |
-Meibomian gland dysfunction
-Chronic recurrent nature -As above treatment -Systemic tetracyclines (doxycycline 100mg per day for 1 mth, then 50mg for 2 mths) -Mild topical steroid (FML) and topical antibiotic 1-2 weeks to reduce inflammation and bacterial load -Optimel antibacterial honey |
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Antibacterial use for:
CHLAMYDIAL CONJUNCTIVITIS |
-Refer
-Oral doxycycline 100mg per day for 10-14 days -one or two 1gm doses of azithromycin -topical treatment ineffective |
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Antibacterial use for:
DACRYOCYSTITIS |
-Bacterial or fungal infection of lacrimal sac and tear drainage system
-Oral broad-spectrum antibiotics -Refer for aspiration if painful, surgical reconstruction |
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Antibacterial use for:
GONOCOCCAL KERATOCONJUNCTIVITIS |
-Acute bilateral sight threatening disease caused by gram-ve diplococcus infection, Neisseria gonorrhoea ⇒ corneal perforation
-Lytic Enzymes in mucopurulent discharge must be washed away -Systemic infection requiring systemic antibiotics -Penecillin, 1gm ceftriaxone intramuscularly daily for 5 days, oral doxycycline, topical gentamycin 1.3% hourly |
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Antibacterial use for:
HORDEOLUM INTERNAL/ EXTERNAL |
-Abscess of sebaceous gland
-Internal (acute staph infection of meibomian gland) -External (acute staph infection of lash follicle and zeiss or moll gland) -Resolve spontaneously -Warm compresses, lid hygiene -Broad-spectrum antibiotic 1 week course (external) -1 week course of oral antibiotic if sig. cellulitis -Epilation or curettage may assist drainage |
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Antibacterial use for:
PRESEPTAL CELLULITIS |
-Infection of subcutaneous eyelid tissue anterior to orbital septum
-Requires urgent systemic treatment -Haemophilus influenza, streptococcus pneumonia cause? -Oral antibiotics for ~10days ⇒ penicillin, cephalosporin -IV application may be required in children or if oral response does not occur |
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Antibacterial use for:
ROSACEA KERATITIS |
-Inflammatory skin condition
-Butterfly rash of cheeks and nose -Posterior blepharitis, corneal involvement -Oral tetracycline(doxycycline 100mg/day for 1mth, 50mg/day for 2mths), erythromycin, or azithromycin -Tear supplements and weak topical steroids helpful |
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Viruses
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-Smallest infectious organisms
-Infect humans, animals, plants and bacteria -Obligate intracellular parasites -Depend on host cells for multiplication -Invades metabolic machinery -Acute disease limited by immune system -Some can be latent (recurrent) -Difficult to destroy without hurting host -Immunisation only option (mostly) |
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Anti-Virals
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-Target specific enzymes
-Difficult to develop (selective toxicity for viruses) -Aciclovir, Vidarabine, Idoxuridine -Many virus specific (in notes) |
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Aciclovir (Zovirax)
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-ANTIVIRAL
-Zovirax, HSV, IV, tablets, ointment -Analogue of guanosine -Inhibits multiplication of herpes simplex virus, varicella zoster virus -Activated by viral thymidine kinase (viral selectivity) -Virus thinks it is a nucleotide -Activated form inhibits DNA polymerase -Minimal side effects -Action: Antiviral agent, sig more effective than older agents -Use: Herpes simplex keratitis -Adverse: Transient mild stinging upon application, superficial punctate keratopathy -Pack: Ointment 3% 30mg/g, 4.5g -Dose: 1cm inside lower conjunctival sac 5 times daily for 14 days or minimum 3 days after healing -Cold sore cream skin lesion versions available over the counter |
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Vidarabine (adenine arabinoside)
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-ANTIVIRAL
-Action: Antiviral agent, nucleoside stops growth of nuclear chain, superseded by acyclovir -Use: Herpes simplex virus -Pack: Compound pharmacy product, 3% ointment -Dose: 1 cm inside lower conjunctival sac 5 times daily for 14 days or minimum 3 days after healing -First drug to become generally available for treatment of herpes simplex virus infections (1980s) |
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Idoxuridine
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-ANTIVIRAL
-HSV, not for ocular use |
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Antiviral use for:
HERPES SIMPLEX |
-Leading cause of corneal opacification and infection related visual loss
-Stromal keratitis or iritis can be present in serious forms -Avoid triggers (sunglasses) -Prompt presentation on recurrence of disease (Px education) -Limit corneal scarring -Topical antiviral agent, acyclovir ointment -90% dendrites healed in 1 week |
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Antiviral use for:
HERPES ZOSTER |
-Varicella zoster virus of trigeminal nerve (shingles)
-Treatment within 72hrs -Early treatment reduces risk of post-herpetic neuralgia -Irreversible ocular damage -Contagious when vesicular lesions present -Oral acyclovir 800mg 5x/day for 7 days -reduces time for lesion healing -reduces duration of viral shedding and new lesion formation -Reduces duration of pain and incidence of other complications -Poor oral bioavailability (poor water solubility) -Valaciclovir 1g 3x/day for 7 days -Enhanced bioavailability (prodrug of acyclovir) -decreased duration of pain -Greater effectiveness -Topical antivirals have little effect -Topical steroids, tear supplements, anti-glaucoma meds may be used to manage long term complications (virus never leaves) |
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Antiviral use for:
ADENOVIRAL CONJUNCTIVITIS (EKC) |
-Broad range of adenoviruses causing it
-Upper respiratory tract infection -Preauricular lymphadenopathy signals viral infection -Gritty, watery, inflamed eyes, photophobia -No effective treatment -progression to viral keratitis -AdenoPlus (diagnostic test) -Highly contagious (hygiene) -Resolution occurs within 2-4 weeks -Antiviral agents ineffective -Tear supplements to improve comfort -Cold packs every 3-4 hours -Topical steroids for early stages when opacities are inflammatory (not scars yet) -Aspirin helpful if sig discomfort -Povidone Iodine (betadine) wash suggested (limited evidence of effectiveness- stings) |
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Antiviral use for:
CYTOMEGALOVIRUS RETINITIS |
-Inflammation of retina caused by human cytomegalovirus
-Occurs in immunocompromised individuals (AIDs) -Cidofovir/ ganciclovir/foscarnet used intraveniously (or injected into eye) if active -Intraocular ganciclovir device -Inhibits viral DNA polymerases at concentrations too low to affect human DNA polymerases -Discontinuation of use is common (Toxic!) |
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Antiviral use for:
MOLLUSCUM CONTAGIOSUM |
-Localised skin infection caused by pox-wart-like viral skin infection
-Self-limiting (3-12mths) -Raised, shiny, white-pink nodules -Around eye can cause follicular conjunctivitis -Good hygiene to avoid reinfection -Treatment is excision not antiviral agents, upon removal lesion resolves |
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Antifungals
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-No topical antifungal available
-Difficult to produce -Ocular antifungal infections are rare -Occur most after surgery or depressed immune system -Fungal spores in farming areas can cause (doesn’t have to be from abrasion) -Causes severe ocular damage -Prompt and effective treatment to avoid loss of eye -Fungal toxins cause damage after fungus eliminated -Tablets and ointments (external) |
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Polyenes
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-Antifungal agent
-Alter fungal cell membrane permeability, bind to sterol moiety of membrane -Poor penetration, intravitreal for endophthalmitis -Highly toxic⇒ retinal damage, renal toxicity, reversible anaemia, fevers, chills, hypotension -Amphotericin B, Nystatin |
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Pyrimidines
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-Antifungal agent
-Flucytosine |
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Imidazoles Azoles and Triazole Azoles
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-Antifungal agent
-Alter fungal cell membrane permeability -Miconazole, ketoconazole (IAs) -Itraconazole, fluconazole (TAs) |
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Fungal Infections
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-Uncommon ocular pathogens
-May be hard to distinguish from bacterial infections (won’t respond to antibiotics) -Occurs in already compromised eye (ocular surface disease, long term steroid use) -Slow, relentless infection |
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Antifungal use for:
FUNGAL KERATITIS |
-Antibiotics inactive
-Ulcer with posterior corneal involvement -pearls on back of cornea -Refer to corneal specialist -Send corneal scrape to lab -Treat with antifungal agents when diagnosed (drugs are toxic to cornea) -Topical and oral antifungal agents -Amphotericin B, Ketoconzole, fluconazole, itraconozole, flucytosine -Frequent administration for prolonged period (12 weeks at least) -Topical corticosteroids are contraindicated |
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Antifungal use for:
ENDOPHTHALMITIS |
-Ocular emergency, urgent referral
-Bacteria cause, unusual for fungi -Entry to eye via wound (surgery, penetrating injury) -Reduce post-operative risk by treating infections before surgery -instil povidine iodine immediately post surgery (reduce risk) -Intravitreal injection of antibiotics (vancomycin, ceftazidine) and steroid (dexamethasone) -Topical, oral and IV antibiotics are ineffective on their own |
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Antifungal use for:
ACANTHAMOEBA KERATITIS |
-Ubiquitous protozoan that rarely infects cornea
-Cease contact lens wear immediately (reintroduce after 6mths) -Lab identification (scraping) -Commence treatment using anti-amoebic drugs after confirmation (propamidine, neomycin and 0.02% polyhexamethylene-biguanide (PHMB) or topical chlorhexidine) -Refer, reviewed weekly until clinical improvement seen |
