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Learn about the various antibiotics and steroids used in ophthalmic practice, their mechanisms of action, effects, and side effects. Explore the drug treatment of certain diseases.
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ANTIBOITICS , STEROIDS USED IN OPHTHALMIC PRACTICE AND DRUG TREATMENT OF CERTAIN DISEASES Dr. Faizur RahmanProfessor of OphthalmolgyPeshawar Medical CollegePeshawar
Learning objectives At the end of the session the students would be able to: • Know various antibiotics and steroids used in Ophthalmic practice. • Describe the rationale of using various drugs. • Mechanism of action , effects and side effects of these drugs. • Know drug treatment of certain diseases
What is antibiotic? • A chemical substance produced by one organism causing the death of other bacterial cells i.e penecillin and streptomycin. • After the introduction of synthetic agents these are now called antibacterials. • As newer agents came up now a wide spectrum of drugs are available called antimicrobials.
Mechanism of action. • Difference between humans and microbes is exploited to produce substances toxic to microbes and harmless to humans. • The selective toxicity may be relative than absolute. • Concentration of antimicrobials must be carefully controlled.
Mechanism of action...Cont. • INHIBIT BACTERIAL CELL WALL OR ACTIVATE ENZYMES THAT DESTROY BACTERIAL CELL WALL: • PENICILLINS • CEPHALOSPORINS • BACITRACIN • VANCOMYCIN • KETOCONAZOLE • MICONAZOLE
Mechanism of action...Cont. • ALTER CELL WALL PERMEABILITY AND LEAKAGE OF INTRACELLULAR CONTENTS • POLYMYXINS • NYSTATIN • AMPHOTERICIN B • COLISTIMETHATE
Mechanism of action...Cont. • INHIBIT PROTEIN SYNTHESIS • Tetracyclines • Aminoglycosides • Macrolides/Ketolides • Clindamycin • Chloramphenicol
Mechanism of action...Cont. • DRUGS THAT BLOCK SPECIFIC METABOLIC STEPS (Foleate inhibitors) • SULFONAMIDES • TRIMETHOPRIM • INHIBIT DNA DEPENDENT RNA POLYMERASE • RIFAMPICIN
Mechanism of action...Cont. • INHIBIT DNA DEPENDENT DNA SYNTHESIS • QUINOLONES • ACT AS NUCLEIC ACID ANALOGUES • ANTIVIRALS
Selection. • Identify the infecting organism • Empiric therapy prior to identification • Determination of susceptibility • Barriers • Patient factors. • Safety of agent • Cost of therapy.
Common Antimicrobials used in Ophthalmology • Chloramphenicol (Topical) • Anti-mycotics(Systemic and topical) • Aminoglycosides(Systemic and topical) • Sulphonamides(Systemic and topical) • Anti-virals (Systemic and topical) • Macrolides(Systemic) • Quinilones (Systemic and topical) • Cephalosporines (Systemic and topical)
Types • Mineralo corticoids • Glucocorticoids • Androgens
Some Corticosteroids • Beciomethasone • Betamethasone • Cortisone • Des oxy cortico sterone • Dexamethasone • Fludro cortisone • Hydrocortisone • Methyl prednisolone • Para methasone • Prednisolone • Prednisone • Triamcinolone
Actions • Promote normal intermediary metabolism: Gluconeogenesis Stimulate protein catabolism Stimulate lipolysis • Increase resistance to stress by: Raising blood glucose level Modest rise in BP • Alter blood cell levels in plasma: Decrease in eosinophils, basophils, monocytes and lymphocytes by redistribution from circulation to lymphoid tissue Increase in the number of RBC, platelets, neutrophils
Actions…Cont. • Anti inflammatory action: (Complex mechanism) Suppression of immunity Indirect inhibition of phospholipase A2 • Alter other endocrine systems: Decrease in ACTH and TSH Increase in GH • Effects on other systems: Increased production of gastric acid, pepsin Effects on CNS Bone loss Myopathy
Indications • In the treatment of ocular inflammations and immune related ocular diseases. • Act by suppressing the formation of arachidonic acid and other mediators by induction mediators like phospholipaze A2 and inhibitory protein Lipocorteins • Prevent edema, Fibrin deposition, capillary dilatation and proliferation, Leukocyte infiltration and subsequent scarring.
Properties and Duration of action • Long acting/ Short acting/ Depot • Very potent • Potent • Moderately potent • Mild
Side effects-Systemic • Impaired wound healing/ Easy Bruising • Negative calcium balance/ Osteoporosis • Increased appetite/ Hyperglycemia/ Diabetes Mellitus • Euphoria/ Depression/ Psychosis • Hypertension • Edema (Sodium and water retension)/ Weight Gain • Peptic ulcers/ GI Hemorrhage/ GI Perforation • Hypokalaemia (Potassium depletion) • Hirsutism /Acne/ Coetaneous striae/ Amenorrhea • Myopathy (Gluconeogenesis) • Avascular Bone necrosis (Neck of femur) • Decreased Immunity
Side effects- Eye • Cataract (PSC) • Steroid induced Glaucoma • Retinal Micro-Aneurysms • Papilloedema • Delayed Wound Healing • Mild Blephroptosis • Immune Suppression-Secondary Infections • CANDIDA, TOXOPLASMOSIS, CMV, HSV,
Routes of administration • Topical • Intralesional • Subconjunctival • Subtenon • Periocular • Intravitral • Intracameral • Systemic oral iv
Commonly used Steroids • Prenisolone (Topical and systemic) • Dexamethasone (Topical and systemic) • Betamethasone (Topical and systemic) • Hydrocortisone (Systemic only) • Loteprednol (Topical only) ( No IOP Rise) • Flouromethalone (Topical only) ( No IOP Rise)
Steroid use in ophthalmology • Intra lesional in hemangioma and chalazion • Iv in optic neurirtis • Oral in dysthyroid ophthalmopathy. Corneal transplant • Intravitreal in CRVO • Topical postoperative, uveitis, corneal transplant • Intracameral Per-op in children
Treatment of Orbital Cellulitis • The patient with orbital cellulitis should be promptly hospitalized for treatment. Hospitalization should be continued until the patient is afebrile and is clearly improved clinically. • Symptomatic; antipyretic, NSAIDS • Antimicrobials ; • Ceftazidime 1 g tds , I/M • Metronidazole 500mg tds, PO • Vancomycin in case of allergy to the above mentioned • Surgical intervention in case of local abscess or unresponsive cases • Consultation with ENT specialist, neurosurgeon & paediatrician if required
Treatment of Orbital Cellulitis • Specifically identified pathogens identified on cultures. • Intravenous antibiotic therapy should be continued for 1-2 weeks and then followed by oral antibiotics for an additional 2-3 weeks. • Fungal infection requires intravenous antifungal therapy along with surgical debridement.
Treatment of Orbital Cellulitis Surgical drainage of an orbital abscess is indicated if any of the following occurs: • A decrease in vision occurs. • An afferent pupillary defect develops. • Proptosis progresses despite appropriate antibiotic therapy. • The size of the abscess does not reduce on CT scan within 48-72 hours after appropriate antibiotics have been administered. • If brain abscesses develop and do not respond to antibiotic therapy, craniotomy is indicated.
Treatment of Trachomatous Conjunctivitis SAFE strategy developed by WHO for trachoma: • Surgery: • To prevent blindness & limits progression of corneal scarring. • Can improve vision. • Antibiotics: • Azithromycin—1 G single dose (adults). • Children: 20mg/kg single dose
Treatment of Trachomatous Conjunctivitis • Erythromycin 250 mg QID for 4 weeks. (children 125mg/kg). • Tetracycline 250 mg QID for 4 weeks. • Topical tetracycline 1% 0.5 inch ribbon BD for 6 weeks. • Facial cleanliness: • Reduces risk & severity of trachoma. • Environmental change: • Improved water supply & household sanitation. • Personal & community hygiene. • Adequate housing & water & sewage system.
Ophthalmianeonatorum • Topical Tetracycline. • Oral Erythromycin 25mg/kg body weight 12 hourly for 14 days. Caution: Examine mother & father for chlamydialurethritis/ cervicitis and treat.
Acute Dacrocystitis • Broad spectrum antibiotics • Analgesics • Drainage if abscess formation
Treatment of Corneal Ulcer (Bacterial) • Initial treatment: Broad spectrum topical antibiotics (Fortified) • Dual therapy: Aminoglycoside & cephalosporin. • Mono therapy: Fluoroquinolone. • Oral antibiotics: • Atropine. • Systemic analgesics.
Treatment of Corneal Ulcer (Viral) • Acyclovir 3% ointment x 5 times daily • Trifluorothymidine 1% drops 2-hourly • Debridement if non-compliance or no response
Treatment of Corneal Ulcer (Fungal) • Polyenes: Natamycin 5%: Filamentous fungi. Amphotericin B: Filamentous fungi. • Imidazole: Miconazole 1%: Candida, Aspergillus. Systemic: Itraconazole, Ketoconazole. • Pyramidine: Flucytosine 1%: Candida.
Treatment of Corneal Ulcer (Acantamoebal) • Topical: Propamidine Isothionate 0.1% (Brolene), Dibromopropamidine Isothionate 0.15%, Miconazole 1%. • Systemic: Ketoconazole.
Treatment of Endophthalmitis • Intravitreal antiboitics • Subconjuntival antibiotics. • Topical antibiotics. • Role of systemic antibiotics. • Role of steroids. • Role of vitrectomy. • Cycloplegics and analgesics.
PRIMARY GOAL To prevent further damage to the eye by lowering IOP & to ultimately prevent blindness
Systemic-Used in Emergency • Plasma Expanders • Urea • Mannitol 20% IV solution. Dose: 1-2g/kg or 5 ml/kg body weight. Up-to 60 drops/min over 20-30 min. Peak of action: within 30 min. Duration of action: up-to 6 hrs. • Diuretics • IV Acetazolimide
Glycerol-Oral • 50% solution. • Oral agent with a sweet & sickly taste. • Pure lemon should be added to avoid nausea. • Dose:1-2g/kg or 2-4ml/kg body weight. • Peak of action: Within 1 hr. • Duration of action: Upto 3 hrs. • Metabolized to glucose in the body.
Isosorbide-Oral • Oral agent with a minty taste. • Dose: Same as for glycerol. • Metabolically inert & can be given to diabetics without insulin cover.