antibiotic drug for eye diseases
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Antibiotic ocular drugs
Presenter : Surendra Prasad SahM.Optom
(13/10/2014)
Modes of administration Topical instillation into the conjunctival sac
Intraocular penetration of topically instilled drugs
Intraocular injections
Systemic administration
Guidelines for effective antimicrobial therapy
Select anti-infective drug to which the microorganism is sensitive
Establish accurate clinical and laboratory diagnosis
Select least toxic anti-infective drug
Establish adequate drug levels at site of infection
Conti…………. Select optimum routes of administration
Use appropriate dosage regimen
Prescribe drug for appropriate length of time
Augment drug therapy with physical procedures
Educate patient
Reasons for antimicrobial failure
Inaccurate diagnosis
Resistant microorganism
Inadequate drug dosage
Inadequate supplemental physical procedures
Inadequate patient immune system response
Patient noncompliance
Microorganisms resistanceProducing an enzyme capable of destroying or
inactivating the antibiotics
Altering the target site receptor for the antibiotics so as to reduce or block its binding
Preventing the entry of the antibiotics into bacterial cell or actively transporting the antibiotic out of the bacterial cell
Antimicrobial therapy
Action Bactericidal
Bacteriostatic
Work Disrupt the wall of cell
Alter cellular membranes or protein production
Disrupt synthesis of vital component s
Alter cellular DNA
What the patient needs to know Always follow doctors instruction when taking anti –invectives.
using drops more often than prescribed may cause a toxic reaction
Always finish the full course
Stomach upset is very common with oral antibiotic therapy
Never use non ophthalmic OTC antibiotics in the eye
Tetracycline products may increase your sensitivity to sun
Vigamox is naturally yellow coloured ,this does not means that drops have gone bad
Relationship between bacterial structure and antibacterial drug action
Drugs affecting cell wall synthesis
Include :-Penicillin
Cephalosporins
bacitracin
Vancomycin
Penicillins
All penicillins contain a common nucleus composed of a thiazolidine ring and beta –lactam ring connected to a side chain
The penicillins act by inhibiting synthesis of the bacterial cell wall
Bacteriocidal agents
Unstable in solution and penetrate the cornea poorly
Commonly used penicillins
Benzyl penicillin
Procaine penicillin
Methicillin ,cloxacillin and flucloxacillin
Carbenicillin
Ampicillin
Amoxycillin
Clinical uses
Generally more effective against gram-positive organisms
Treatment of syphilis and syphilitic eye disease(stromal inflammation and vascularisation ,episcleritis ,scleritis ,papillitis ,retinal vasculitis ,exudative retinal detachment)
To treat respiratory infections in children
Mild preseptal cellulitis
Treated before nasolacrimal duct irrigation ,probing or surgery is performed
Side effects Hyper-sensitivity responses
Pain and tenderness at the site of an intramuscular injection
Central nervous system include headache,dizziness,confusion
May experience nausea,vomitting or diarrhea
Cause oral contraceptive to fail
Breast cancer may developed
Cephalosporins
First –generation:-
Include:- cephradine , cephalexin ,cefadroxil ,cefazolin
Uses:-all act effectively against gram –positive bacteria , corneal ulcers
Second –generation:-
Include:-cefaclor, cefuroxime ,cefoxitin , cefotetan
Uses:-mild preseptal cellulitis
Conti………
Third –generation :-
Include:- cefotaxime , cefixime , cefotetan
Uses:-endophthalmitis,preseptal cellulitis,gonococcal ophthalmia neonatorum
Fourth –generation:-
Include:-cefepime
Uses :-activity for both gram- negative and positive organisms
Side effects
Decreased renal function
Unusual serum sickness
Breast cancer developed
Vitamin k deficiency may developed
Bacitracin
Inhibits bacterial cell wall synthesis by inhibition the movement of a precursor of peptidoglycan though the cell membrane from the cytoplasm to the cell wall.
Clinical uses
To treat skin and mucous membrane
Mostly against gram –positive bacteria
Treat minor skin cuts and abrasions
Superficial eye infections
Treating staphylococcal blepharitis
Drugs affecting the cell membrane
Include :-
Polymyxin B
Gramicidin
Polymyxin B
• A cationic detergent or surfactant that interacts with the phospholipids of cell membrane ,thus disrupting the osmotic in integrity of cell.
• This increases the bacterial cell’s permeability and causes cell death .
Clinical uses
Treat skin infections and external otitis
Treat infection of lids and conjunctiva
To prevent infection when conjunctiva or cornea is compromised
Side effects
Irritation and allergic reactions of the eyelids and conjunctiva
Causes pain, chemosis and tissue necrosis when administered by subconjunctival injection
Drugs affecting protein synthesis
Include:-
Aminoglycosides
Tetracyclines
Macrolides
chloramphenicol
Aminoglycoside Inhibit bacterial protein synthesis by binding to 30s
subunit of the bacterial ribosome
Include:- Gentamicin
Tobramycin
Neomycin
amikacin
Clinical uses
Neomycin :- To treat a variety of skin and mucous membrane infections
Active against most gram –negative bacilli and some gram-positive cocci
Gentamicin:- To a variety of bacterial infections of the external eye and
conjunctivitis, blepharitis and kerato-conjunctivitis
Initial treatment of bacterial corneal ulcers
Conti……….
Tobramycin:- Treatment of corneal ulcer
Amikacin:- Treatment of gram-negative bacillary infections
Treatment of bacterial endophthalmitis
Side effects
Neurotoxicity manifest as auditory and vestibular ototoxicity occurs
Nephrotoxicity
Corneal toxicity –punctate epithelial erosions ,delayed reepithelization and corneal ulceration
Conjunctival toxicity –chemosis, hyperemia and necrosis
Tetracyclines
These are broad-spectrum bacteriostatic agents with a considerable action against both gram-positive and gram – negative organisms as well as some fungi .
Includes tetracycline , chlortetracycline and oxytetracycline
Clinical uses
In adults with chlamydial ocular infection such as inclusion conjunctivitis or trachoma
Not cause chemical conjunctivitis typically produced by silver nitrate
Effective therapy for noninfectious condition eye such as acne rosacea or meibomianitis
Effective for resolving noninfective corneal ulcers or ‘corneal melting ’
Side effects
Heartburn , nausea , vomiting ,diarrhea commonly occurs
Cause azotemia in patients with impaired renal function
Bone growth depression and tooth discoloration
Lightheadedness , loss of balance ,dizziness, nausea beginning 2 to 3 days
chloramphenicol
clinical uses:- Active against most gram-positive and gram-negative bacteria
Effective against most bacterial infections of the external
Side effects:- Dose-related toxic effect cause a bone marrow depression
Bone marrows depression consists of aplastic anemia
Drugs affecting folate metabolism
Include :-
Sulfonamides :-act by inhibiting bacterial synthesis of folic acid ,a chemical required for synthesis of nucleic acid and protein
Pyrimethamine and Trimethoprim :-reversibly inhibit in the synthesis of folic acid by inhibiting the enzyme dihydrofolate reductase ,which catalyzes the reduction of dihydrofolic acid to tetrahydrofolic
Clinical uses
Treatment for acute uncomplicated urinary tract infection
Treatment the protozoan disease toxoplasmic retinochoroiditis
Treatment of blepharitis and conjunctivitis
Treatment of blepharoconjunctivitis
Treatment of bacterial pediatric infection
Side effects Gastrointestinal disturbances including nausea ,vomiting and diarrhea
Allergic skin reactions such as rash and urticaria and more severe Stevens –johnson syndrome can occur
Cause blood dyscrasias
myopia ,with or without induced astigmatism has been reported
Photosensitization which can result in sunburn on lid margins or skin of face
Patients experience a hypersensitivity reaction consisting of lid edema ,itching, increased redness, tearing or periocular rash
contraindications
Patients with known hypersensitivity or intolerance to any member of this drug family
Pregnancy at term ,for nursing mothers and for infants less than 2 months
Patients with documented blood dyscrasias
Patient taking oral hypoglycemic dugs
Drugs affecting bacterial DNA synthesis
Drugs that inhibit bacterial DNA synthesis include fluorinated quinolones (fluoroquinolones ),which are structurally related to nalidixic:
Lomefloxacin
Norfloxacin
Enoxacin
Ciprofloxacin
Sparfloxacin
Germifloxacin
Levofloxacin
gatifloxacin
moxifloxacin
Clinical uses
Extremely effective bacteriocidal drugs and against gram-negative
Only ciprofloxacin and ofloxacin are approved by FDA for treatment of corneal ulcers
Treatment of complicated urinary tract infections and prosatitis and sinusitis
Treatment of bacterial conjunctivitis
Treatment of more serious infection and bacterial karatitis
Side effects
Gastrointestinal , dermatologic ,central nervous system reaction and photo toxicity
Local burning or discomfort ,bitter taste after instillation ,white precipitates ,FB sensation, itching and conjunctiva hyperemia , chemosis and photophobia
Treatment of corneal ulceration can result in white precipitates
contraindications
Patients with a history of hypersensitivity to any drug in family
Caution in patient with central nervous system disorders
Not recommended for systemic administration in children ,adolescents younger than age 18 years or pregnant women
References
clinical ocular pharmacology Jimmy D.bartlett
Siret D. jaanus
Modern pharmacology with clinical application
Charles R.craig
Robert E.stitzel
Ophthalmology A.K.khurana
Discussion
Thank you
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