Transcript Jane Goodwin BSc, MSc Nurse Practitioner

Jane Goodwin BSc, MSc
Nurse Practitioner
Drugs and the Eye
A&P
A&P
Pharmacology
• A solution is a liquid vehicle for drug
delivery to the eye.
• Solutions have a shorter contact time.
• Drops drain into lacrimal apparatus, into
the nose and are absorbed systemically.
• Drops needs to be sterile therefore free
from bacteria, viruses, and fungi.
• Preservatives are added to inhibit the
multiplication of organisms.
• Some solutions oxidise when exposed to
air which can alter their chemistry.
• The shelf life of drops are 1 month
•Preservative free drops are supplied in single
dose units ‘Minims’ and used once
• Most eye solutions are expressed as ‘per
cent’. This translate to grams / 100ml.
EG – 0.5% Chloramphenicol = 500mg of
Chloramphenicol in 100ml of solution.
• Advantages of administering the drug
locally is that is delivers the agent directly
to the site of action.
• Its effects are more immediate.
• Smaller doses are used.
• Systemic side effects are minimised.
Administration
• Locally – direct into lower eye lid.
Subconjunctival injection – space
between conj and sclera
Retrobulbar Injection - into muscle
cone behind the eye
• Peripubulbar – into space around the eye
• Intraocular – into the eye eg Anterior
Chamber
Intraocular Lens
•Contact lens – impregnated and placed on cornea
Edge of lens
Absorption
• Drugs applied topically enter the eye
through the cornea
• There are 5 layers to the
Cornea
Descemet’s
Membrane
Internal Layer
Endothelium
• The outer most layer have a high lipid content
(lipophilic)
• The innermost layer have a high water content
(Hydrophilic)
• Drugs therefore have to require both lipophilic
and Hydrophilic properties
• PH of eye drops range between 3.5 – 10.5 which
is to aid absorption
• Factors that can influence absorption include
trauma to the cornea – increasing the amount
absorbed
• Drugs can also bind to contact lenses therefore
reducing their effectiveness and cause damage
to the contact lens
Other factors affecting absorption
• Drops can be lost from the eye before they
cross the cornea.
Occlude Inner Canthus
Types
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Antibiotics
Antihistamines
Anti-virals
Mydriatics – dilation of pupil 2 types – parasympatholytic
& Sympathomimetic
Miotics – constrict the pupil
Glaucoma drugs -Carbonic anhydrase inhibitors, Betablockers, Alpha 2 agonists
Steroids
Local anaesthetics
Diagnostic
Tear Replacement
Mydriatics
- are used to dilate the pupil for the following reasons
• To examine the retina
• To maintain dilatation of the pupil in
uveitis, with corneal ulcers, severe corneal
abrasions and after surgery
• To break down posterior synaechiae in
uveitis
• To allow a cataract to be extracted and
retinal surgery
• Refraction in children
2 types
• Parasympatholytics – which cause
mydriasis and cycloplegia (relaxing
circular iris muscle causing paralysis of the
ciliary muscles)
E.g. atropine, tropicamide and
cyclopentolate
• Sympathomimetics - mydriasis (stimulating
the radial muscle of the iris to contract
causing the pupil to dilate)
E.g. adrenaline and phenylephine
Side Effects and Cautions
• Causes blurred vision therefore driving not advised
• Systemic absorption can occur causing anticholinergic
effects such as tachycardia, dizziness, dry mouth,
constipation and hypertension
• Due to risk of systemic absorption should be used with
caution in people with hypertension, heart disease and
thyrotoxicosis
• Can cause a rise in intra ocular pressure (IOP)
• Contraindicated in glaucoma especially narrow angle
glaucoma
• Contra-indicated with MAOI’s (monoamine oxidase
inhibitors) – risk of hypertensive crisis
Miotics
• Miotic drugs constrict the pupil and ciliary
muscle which opens up the drainage channel for
aqueous flow. It main use is in the treatment of
Acute Glaucoma
• Pilocarpine 1% 2% and 4% (most common)
Acute Glaucoma
IS SIGHT THREATENING!
Is a sudden rise in intra ocular pressure.
This is caused by an acute blockage in the
drainage system – stopping the aqueous
humour drain from the eye. Symptoms
include a red painful eye, reduced vision,
nausea, headache and can be in one or
both eyes.
Normal Flow
Acute blockage
Miotics - Cautions
• Causes - Headache/browache in long term use..
Usual burning itchy and sensitivity with drops.
• Blurred vision and restricted vision -
• Patient on long term treatment need monitoring
for field s and IOP’s.
• Avoid in conditions where a miosed pupil would
be undesirable ie Iritis and Uvietis
Chronic Open Glaucoma
• The angle is open – but other parts of the
drainage system can be affected.
• Slow onset, irreversible sight loss, hereditary,
more common in elderly and Afro-Caribbean's
• Caused by a persistent low grade rise in
intraocular pressures (normal readings are
between10 - 21mmHg). Therefore readings
above 22 - 35 mmHg may require monitoring
and treatment.
• It causes damage to the retinal nerve fibres
known as cupping of the disc making the disc
pale and a change in shape.
Circulation of Aqueous
= problem with aqueous drainage
Other Glaucoma Drugs
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Carbonic anhydrase inhibitors
Beta blockers
Alpha 2 agonists
Prostaglandin analogues
Sympathomimetics
Combinations of the above i.e. Carbonic
anhydrase inhibitors and Beta blockers
Carbonic anhydrase inhibitors
• Carbonic anhydrase is an enzyme necessary for the
production of aqueous. These drugs therefore reduce the
production of aqueous.
• Uses - Acute, Chronic and secondary Glaucoma
• Ocular SE – Local eye irritation and taste disturbance
• Systemic SE –drowsiness, GI, nausea, upset potassium
levels and is a weak diuretic
• Types – Oral and IV -Acetazolamide (Diamox) not used
long term mostly in acute cases
• Examples - Topical – Dorzolamide (Trusopt) and
Brinzolamide (Azopt)
Beta Blockers
• Are relatively safe, efficacious and usually first line
treatment.
• Work by affecting the production of aqueous in the ciliary
body and increase the outflow of aqueous in trabeculae
meshwork
• Uses – primary open angle glaucoma
• Ocular SE – dry eyes, blurred vision, eye irritation
• Systemic SE – bronchospasm in asthmatics,
bradycardia and can mask manifestations of
hypoglycaemia
• Examples – Timolol (Timoptil), Betaxolol (Betoptic),
Carteolol (Teoptic) and Levobunolol (Betagan).
Alpha 2 Agonists
• Is used as add on therapy when beta blockers are not
enough to reduce IOP or when B’blockers are contraindicated.
• Works by enhancing drainage from the eye and
decreasing production of aqueous.
• Uses – primary open angle glaucoma and pre op
• Ocular SE – dry eyes, blurred vision, eye irritation and
stinging
• Systemic SE – Headache, changes in heart rate, rhythm
an BP as well as anxiety and tremor
• Examples – Apraclonidine (Iopidine) and Brimonidine
(Alphagan)
Prostaglandin Analogues
• Work by increasing uveoscleral outflow
• Uses – open angle glaucoma and *ocular hypertension
• Ocular SE – brown colour changes in the iris and
lengthening of the eyelashes
• Examples – Bimatoprost (Lumigan) and Latanoprost
(Xalatan)
• *NB – ocular hypertension is when the IOP is normal but
there is signs of the disease from the visual field tests
and optic disc defects.
Sympathomimetics
• Dipivefrine is a pro drug of adrenaline. It is
claimed to pass more rapidly than adrenaline
through the cornea and is then converted to the
active form.
• Works by increasing the outflow of aqueous
through the trabecular meshwork.
• It is contra indicated in angle closure glaucoma
because it is a mydriatic (dilating drug)
• Ocular SE – severe smarting and stinging
• Systemic SE – caution with pt’s with
hypertension and heart disease.
Tunnel Vision
Coffee Time !
Microbiology of the eye
Micro-organisms can gain access as a result
of:•
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Direct Contact e.g. Herpes simplex
Air-Bourne infections
Insect-Bourne infections e.g. Trachoma
Migration of bacteria from nasopharynx
Trauma
Infected contact lenses
Infected eye drops and lotions
Infected instruments
Conjunctivitis – most common
cause of Red Eye
Types of conjunctivitis
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Bacterial
Viral
Allergic
Secondary
Chronic
Bacterial Conjunctivitis
• Acute onset
• Bilateral
• Red, gritty, sore, puffy
lids and purulent
discharge
• Resolves within 5-10
days
• Rx G.Chlor or Fusidic
acid
Viral
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Acute onset
Related to other URTI
Likely to be Unilateral
Red, gritty sore, Watery
discharge
• Corneal staining with
Fluorescien
• Diagnosis difficult in
Primary Care therefore
refer a unilateral red eye if
no improvement within
48hrs of Rx
• Last for 3 -4 weeks
Allergic
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Acute onset
Bilateral
Hx of exposure to allergens
Hx Atopy or Fhx
Sx – very itchy,watery,
chemosis (jelly like) of conj,
puffy lids, follicles on Tarsal
Plate (under eye lid)
• Responds to antihistamines,
remove from cause
• Should respond immediately to
Rx
• Prophylactic treatment
recommended.
Drugs for allergic conjunctivitis
• Topical antihistamine drops (H1 antagonists) –
antazoline, azelastine and levocabastine provide rapid
relief and can be used for up to 4/52.
• If prolonged relief is required a mast cell stabiliser eg
lodoxamide, nedocromil and sodium cromoglycate
• Start their use ideally 1/12 before allergy season
• Diclofenac is also licensed and steroids can be used
only after examination on a slit lamp and seen by an
ophthalmologist
• Eye sx alone are best treated topically, however if a pt
has other sx oral antihistamines are recommended
Secondary
Corneal Abrasion
Corneal Foreign Body
Herpes – Dendritic Ulcer
Corneal Ulcer, with pus in AC
Chlamydia
• Serotypes D-K are genital
• Serotypes A-C causes
Trachoma – worlds
leading cause of
blindness
• It attacks mucous
membranes & inhibits
host cell protein synthesis
• Topical Rx tetracycline
ointment QDS 6/52
• Systemic - Doxycycline,
Tetracycline or
Erythromycin
Under surface of eye lid (sub tarsal plate)
Chloramphenicol
• Broad Spectrum Abx with least overall
resistance
• It is a bacteriostatic and inhibits bacterial
syntheses by reversibly binding to ribosome's
which disrupts peptide bond formation and
protein synthesis
• Acts on Gram +ve and –ve organisms
• MUST be stored in the fridge
• Bathe away discharge before use
• Regime – 2 hourly in severe cases for 24 hours
then QDS for 5 – 7 days.
Side Effects/Cautions
• Stinging, local discomfort
• Greater chance of allergy than Fusidic acid
• Aplastic anaemia (bone marrow suppression)
check FHx and GH
• Gray Baby syndrome
• Avoid in pregnancy, breast feeding and with
caution in under ones
• Check bloods regularly if using long term
• Not sensitive to Pseudomonas
Fusidic Acid
• Is a bacteriostatic and bactericidal agent with a steroidlike structure of no glucocorticoid activity.
• Inhibits bacterial protein synthesis and prevents
elongation of the peptide chain.
• It is chemically unrelated to any other antibacterial in
clinical use
• There is no cross-resistance nor cross sensitivity
between Fusidic acid and other antibacterials
• It is microcrystalline giving it sustained release properties
therefore concentration is maintained for 12 hours in
lacrimal fluid and aqueous humour (BD dose regime)
Side Effects/Cautions
• Stinging, local discomfort, burning redness
and watering on initial instillation
• Allergic reactions are less than
Chloramphenicol
• Not known to be harmful in pregnancy
• Is excreted in breast milk – not known to
be harmful – weigh up risks/benefits.
• Can be local variations of resistance
Antibiotic efficacy against common
ocular pathogens
Pathogen
* Known Activity
Fusidic Acid
Chloramphenicol
Staph’ Aureus
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Staph’ epidermis
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Strep’ pyogenes
Sensitive
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Strep pneumoniae
Sensitive
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Escherichia coli
Resistant
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Haemophilus influenzae
Sensitive
*
Pseudomonas
Resistant
Resistant
Gonorrhoea
OTC products for conjunctivitis
• Brolene and Golden Eye are antiseptic not
antibiotic
• They are of little use
• They commonly cause an allergic reaction
which compounds the patients symptoms
• They are used in acanthamoeba keratitis
(organism grown on contact lenses)
• Chloramphenicol is now OTC
Advice to patients
• Conjunctivitis is self limiting and will resolve
without Rx in mild cases
• Clean eyes with cooled boiled water
• Avoid touching and rubbing eyes
• Wash hands after touching eyes
• Avoid sharing towels/face cloths
• Throw away make up that may be contaminated
• Contact Lenses SHOULD NOT be worn due
episode and leave for 48hours after finishing Rx
Contact Lenses
• Types include soft, hard (gas
permeable) disposable and
extended wear.
• Should not be worn during
infections
• Strict hygiene, cleaning and
maintenance should be
encouraged at all times
• Soft CL are not compatible with
drops that contain preservatives
• Soft CL absorb Fluorescein and
permanently stain
Instilling eye medication
• Drops contain preservatives
to prevent micro-bacterial
growth
• 1/12 shelf life-throw out after
• Clean discharge away first
• Wash hands
• Pull on lower eyelid to make a
‘well’ – drop solution or
squeeze ointment into eye.
• Avoid touching the tip of the
bottle with the eye
Anti-virals
• Herpes Simplex and Zoster
• Acyclovir (Zovirax) comes in tablet and
oral form and used for both types of
herpes. Ointment is used 5 x a day and
compliance is essential to ensure
disruption of the DNA synthesis.
• Pt’s should be monitored by an
ophthalmologist as corneal scarring will
occur
• Side effects from topical Rx include
irritation, stinging, itching, inflammation,
pain and photophobia
Oral & Topical Steroids
Overdose or prolonged use can
exaggerate some of the normal
physiological actions of
corticosteroids leading to
mineralocorticoid and
glucocorticoid side effects
• Adrenal suppression amongst
many things can cause
Conjunctivitis.
• Suppression of infection therefore masks sx and
exacerbates infections e.g.
bacterial, viral and fungal
• Causes – next slide
Cataract
Systemic steroids
have a high risk
(75%) of inducing a
cataract
Glaucoma
Papilloedema
Sclera Thinning
Amiodarone
• Used in Rx for arrhythmias
• Has a very long half life extending to
several weeks.
• SE’s can cause reversible corneal
deposits (causes night glare), Optic
neuritis – causing blindness
• Treatment MUST be stopped and expert
advice taken
Amiodarone
Blurred Vision
Optic Neuritis
Corneal Deposits
Antimalarials
• Hydroxychloraquine and chloroquine are
also used to treat Rheumatoid arthritis and
SLE
CAUSES
Ocular Toxicity
Retinal damage
&
Keratopathy
(Corneal Deposits)
Royal College of Ophthalmologists
• Recommend regular ophthalmic examination
• Arrangement should be made locally between prescriber
and ophthalmologist and agreed management plan for
those on long term treatment of 5 yrs or more.
• Va - distance and near recorded before, during and after
Rx
• Any visual impairment needs to be assessed and
recorded before, during and after Rx
• Any deterioration in vision MUST be assessed by
ophthalmologist
• Children receiving treatment for Juvenile Arthritis should
be screened for Uveitis
TB Drugs
Ethambutol is included in a Rx regime when
there is resistance to other TB drugs
• SE’s – Loss of VA
• Colour Blindness
• Reduction and restriction in Visual Field
The dark patches
show loss of
vision
• Side effects are more common when given in
excessive doses
• The drug should be stopped at the earliest
presentation of ocular toxicity
• Always advise pt’s to stop Rx and seek medical
and ophthalmic help
• Eye sight is nearly always restored if
discontinuation of drug is early enough
• Pt’s who may not understand warnings about
visual sx should be given an alternative TB drug
if possible
• Children under 5 may not be able to report
changes
Visual Acuity
should be
tested before
starting
treatment
Other Systemic Drugs
• Tamoxifen – oestrogen
antagonist
Causes visual
disturbances including
corneal changes,
cataracts and Retinopathy
• Digoxin Toxicity – causes
visual disturbance
• MAOI’s (monoamine
oxidase inhibitors) –
causes blurred Va,
Nystagmus and interacts
with Sympathomimetics
e.g. Phenylephrine (drug
used to dilate pupil)
Retinopathy
Diagnostic Drops
• Fluorescein – Orange die
• Stains conjunctival and corneal epithelial
damage e.g. corneal ulcers, erosions, and
conjunctival or corneal abrasions
• Assessment of dry eye
• Tonometry
• Fluorescein is available as drops or as
paper strips
• Fluorescein grows pseudomonas
therefore is always used in single dose
units
• It is also used IV so photographs can be
taken of retinal blood vessels, optic disc
and macula
Blood
vessels
Optic disc
Scar
Rose Bengal
• Stains dead conjunctival and corneal
epithelium in dry eye syndrome.
• It causes pain and stinging on instillation
Dead Corneal epithelium
Dry Eyes
3 Layers of Tear Film
Artificial Tears
• Are used for dry eyes and must be used
as often as possible to keep the eyes
feeling comfortable.
• Can be as often as every hour
• Once diagnosed – drops will be necessary
for life
• Dry, hot, windy conditions exacerbate sx
also reading, using PC (Starring for long
periods)
Types
• Drops include – Hypromellose, Tears
Naturelle, Liquifilm
• Gel tears – ‘Viscotears’ – bind with own
natural tears and stay in eye for longer
• Ointments – used at night, stay in eye for
longer, can cause blurring of vision.
List 3 things you’ve learnt
• 1
• 2
• 3
• Try and remember them!!!!
Resources
• http://www.goodhope.org.uk/departments/eyede
pt/dropsfor.htm
• http://www.bnf.org
• Maclean H (2002) The Eye in Primary Care,
Butterworth Heinmann.
• Galbraith et al (1999) Fundamentals of
Pharmacology, Addison Wesley Longman Ltd
• Spalton et al (2006) Atlas of Clinical
Ophthalmology 3rd Ed, Elsevier Mosby
Any Questions