PHARM - Oral Medications and the Eye - Week 6 Flashcards

1
Q

What route of drug administration is more likely to cause adverse effects?

A

Oral and injectables

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2
Q

How do topical eye drugs enter the blood stream (3)? Give percentages.

A

Direct absorption across the conjunctival blood vessels (30%)
Draining via naso-lacrimal duct, into nasal cavity, and eventually the gut (70%)

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3
Q

What absorption mode can give direct access to the CNS? Is it fast or slow?

A

Cross membranes of the olfactory nerve, is fast

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4
Q

True or false

All topical eye drops/ointments will be absorbed into the bloodstream.

A

True

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5
Q

Describe the double D method for minimising systemic eye drug absorption. Explain why it works briefly.
By how much does this reduce systemic absorption?

A

Dont open eyes for 1-2 mins (minimises conjunctival flow)
Digital puncta occlusion (reduces punctal access)
Reduces [drug] in blood by 65-70%

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6
Q

Is it easy for drugs to absorb into the cornea?

A

No, its a challenge

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7
Q

What is the best formulary for corneal absorption? What is a problem with it?

A

Acetate formulary

While it has rapid absorption, it borders on toxicity

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8
Q

What is the rule of thumb for eye drop formularies in order of use (3)?
Describe the general effect and duration for each formulary (if applicable).

A

Acetate > alcohol&raquo_space; phosphate
Acetates are more toxic but can be at a lower dose that avoids it, the effect is short lived and may require multiple drops.
Phosphates have a slower absorption with longer duration of non-toxic therapeusis.

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9
Q

What are 6 classes of drugs that optometrists can prescribe?

A
Allergy
Anti-inflammatory
Analgaesics
Antibiotics
Antivirals
Anti-glaucoma
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10
Q

How can ocular lubricants be useful as an anti-allergy agent?

A

They can wash/remove/dilute an antigen

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11
Q

Can vasoconstrictors be used for mild non-specific hyperaemia?

A

Yes

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12
Q

What is a good agent to use for mild allergic conjunctivitis?

A

Vasoconstrictors like alpha-adrenergic agents

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13
Q

Give an example of an alpha-adrenergic vasoconstrictor.

A

Phenylephrine

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14
Q

What action do astringents have and what are they useful for?

A

They reduce mucoid discharge in allergic surface disease and is a useful anti-allergy agent

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15
Q

What is the hallmark of allergic eye disease?

A

Itch

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16
Q

Mast cell stabilisers are useful as what?

A

Anti-allergy agents

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17
Q

What histamine receptors are anti-histamine eye drops selective for?

A

H1 selective

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18
Q

What histamine receptors are mast cell stabiliser eye drops selective for?

A

H1 selective

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19
Q

What does pre-treatment with mast cell stabiliser eye drops result in?

A

Minimises expression of allergic eye disease

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20
Q

Are anti-inflammatory agents also anti-allergy?

A

Generally yes

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21
Q

How do NSAIDs work in the eye (3)? What agent do they act as?

A

Inhibit COX enzymes, decreasing prostaglandin synthesis, and reducing prostaglandin mediated inflammation.
They are anti-inflammatory agents.

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22
Q

Corticosteroids inhibit what pathway?

A

Intracellular receptor mediated inhibition of inflammatory cascade

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23
Q

Corticosteroids inhibit the activity of what two cells in the eye?

A

Fibroblast and keratocyte activity

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24
Q

List two examples of antimetabolites and what agents they act as.

A

Calcineurin and T-cell inhibitors

As anti-inflammatory agents

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25
What is a good rule of thumb on treating eye inflammation?
If it is no deeper than the iris, topical therapy should suffice.
26
What should be considered if inflammation is deeper than the iris (4)?
Oral, intraocular/sub-conj./sub-Tenon's injection
27
The use of what drug class will control post-op cystoid macular oedema? Describe why.
Topical use of NSAIDs It inhibits PG production in the anterior eye, rather than the retina, and will reduce overall ocular PG load at the posterior pole
28
Are steroid complications more or less likely with long duration of use?
More likely
29
Does topical steroid use promote or inhibit microbial activity? How does it affect would healing?
Promotes microbial activity | Delays would healing
30
List 5 ocular related adverse effects that occurs with long-term topical steroid use.
``` Increased IOP - glaucoma Cystoid macular oedema Rebound inflammation Aggravated dry eye Cataract ```
31
How should steroids generally be used?
Use them hard to suppress inflammation but only for short terms <4 weeks
32
List 3 ocular related adverse effects that occurs with long-term periocular steroid use.
-as for topical use Ptosis Scleral melt and perforation
33
List 6 adverse effects that occurs with long-term oral/systemic steroid use.
``` Weight gain Peptic ulcer Opsteoporosis Diabetes Hypertension Cushing syndrome ```
34
Describe a possible dietary link to inflammation. Comment on essential fatty acids 3 and 6, as well as the Western diet in this context.
Cell membranes produce free fatty acids in the presence of PLA2, which is produced in large amounts during inflammation. n-6 pathway favours pro-inflammatory cytokine production. n-3 pathway favours anti-inflammatory cytokine production. The western diet has a high intake of n-6.
35
What can be used for pain in the case of iritis or uveitis?
Cycloplegic agent
36
Is penicillin commonly used in eye care?
Rarely
37
What is the second line drug for most eye/eyelid infections? Why?
Amoxycillin - due to adverse effects
38
List an adverse effect of amoxycillin.
Hypersensitivity reaction - mostly skin rash
39
What is the first choice ophthalmic drug for eye care and why?
Cephalosporins due to low adverse effects
40
Are cephalosporins bactericidal or bacteriostatic?
Bactericidal
41
List two adverse effects of cephalosporins.
Allergy/hypersensitivity | Prolonged use can impair blood clotting
42
What is a possible consequence of using cephalosporins?
It can destroy GI bacteria that synthesise vitamin K, which is why long term use can impair blood clotting
43
Given its adverse effects, in which individuals are cephalosporins contraindicated?
Haemophiliacs
44
List two examples of macrolides. Are they bacteriostatic or bactericidal?
Erythromycin Azithromycin Are bacteriostatic
45
Are macrolides used in eye care? Explain.
Not generally, as they are bacteriostatic | Good anti-infective for chlamydia however
46
What infection are macrolides good for, how do they work (briefly), and what is the alternative if contraindicated?
Good for chlamydia Work by inhibiting protein synthesis by binding 50S Tetracyclines the alternative
47
What is the most effective tetracycline in eye disease and why is its use limited?
Doxycycline - limited due to bacterial resistance
48
How does doxycycline act.
Inhibits protein synthesis by binding 30S
49
What tetracycline has the fewest adverse effects?
Doxycycline
50
What antibiotic has an effect on meibomian glands and what does it do (2)? How is it used in this context and how long?
Doxycycline - alters MG function and tear flims | Used long term (up to 6 months) for dry eye disease
51
What antibiotic has excellent broad spectrum properties and is only reserved for serious corneal infections? What drug class does it call under? Is it bacteriostatic or bactericidal?
Ciprofloxacin - bactericidal by inhibiting DNA gyrase
52
What are two corneal adverse effects of ciprofloxacin?
Slows corneal healing and promotes perforation
53
What antibiotic drug class is reserved for the more serious eye infections?
Fluoroquinolones
54
Briefly explain how guanine analogs work (4) and what they are.
They are antivirals. They are prodrugs that are activated into a monophosphate by viral thymidine kinase They then undergo phosphorylation to triphosphate by host kinases It is incorporated into viral DNA, which terminates replication
55
What are guanine analogs activated by and into what form? | What happens it it after that and by what?
Viral thymidine kinase to monophosphate form | Phosphorylated to triphosphate by host kinases
56
Why are guanine analogs effective as antivirals?
Viruses have fast replication - the effect is large and desirable
57
Why are adverse effects generally minimised when taking guanine analogs?
Healthy human cells have slow replication as opposed to viruses, minimising adverse effects
58
What is a common side effect of guanine analogs?
Some SPK
59
How can guanine analog side effects be further reduced?
Effects on human cells can be reduced by using them for a limited time
60
What are three indications for guanine analog use?
Treatment/prevention of herpes simplex virus Shingles Chickenpox in immunocompromised individuals
61
How are drugs for herpetic eye infection administered? Can oral be used for acute treatment?
As an ointment | Oral not used for acute treatment
62
Give two examples of a guanine analog. | Which has better absorption/bioavailability?
Acyclovir and famcyclovir | Famcyclovir has better basorption and bioavailability
63
When treating shingles, within what timeframe of symptom onset must the treatment be started?
Within 72h of symptoms manifesting
64
Which has a better safety profile, acyclovir or famcyclovir?
Famcyclovir fam
65
Is famcyclovir available in Australia for eye treatment>
No fam, just acyclovir
66
Which is more cost effective - oral acyclovir tablets or acyclovir ointment? Explain.
Oral therapy is more expensive and not cost effective over ointment - EXCEPT in children
67
Name two ways IOP can be lowered.
Decreasing aqueous production | Increasing drainage
68
How can aqueous production be lowered (2)?
By targetting adrenergics aB and carbonic anhydrase inhibitors
69
List 6 reasons why children rceive excess dosage (if going by adult doses).
Smaller eye Greater absorption of drugs in children Immature metabolic pathways Dose not tailored for children's mass Eye dropper volume is too large for children Smaller blood volume gives greater circulating dose
70
What magnitude does a child's smaller blood volume increase circulating drug dose?
x20
71
What drugs are safe for children >2 years of age (2)?
All of them except anti-histamines
72
What glaucoma medications should be avoided in children (2)?
Avoid alpha agonists if <2 | Avoid beta blockers
73
What are two danger signs with kids?
Loss of vision | Fever (red eye)
74
Most childhood red eyes are what?
Viral infection
75
What is an intense sudden onset of pain indicative of?
FB/abrasion
76
If a child has an abrasion, is patching recommended?
No
77
What is a good way to see if anaesthetic has been administered onto a crying child's eye?
Fluorescein/anaesthetic combo - load it onto the crying eye and use fluorescein to check
78
What is recommended for pain in children (in their eye obviously)? If it doesn't resolve after 24h, what is recommended?
Homatropine | If unimproved after 24h, suspect internal FB
79
What should you always consider if a child has pain in their eyes?
Internal FB
80
What is a common cause of naso-lacrimal duct obstruction in children?
Age related imperforate membrane at distal end
81
What should not be missed concerning a naso-lacrimal duct dysfunction? What is it, and what is the recommended action (3)? Are antibiotics given? What if it hasnt resolved after 13 months?
Red, purulent discharge from the duct Indicates dacryoadenitis Needs parental reassurance of 90% remittance by 1 year Lid hygiene, heat/massage No antibiotics are given Probe or refer if unresolved after 13 months
82
What is advised for insect bites?
Anti-histamines
83
Are antibiotics used for children with conjunctivitis? What is the best therapy? Why is this so (2)?
Yesd Best therapy is delayed antibiotic (3 day) Produces less drug resistance and allows the body to heal
84
True or false | All eye drops will cross the placenta and have the potential to harm to foetus.
True
85
Are all anti-infectives safe to use in pregnancy and lactation?
Yes
86
Are NSAIDs a concern for pregnant women?
Short term low dose - no
87
Are steroids safe to use in pregnancy?
Category A is safe
88
What can be said of glaucoma and anti-glaucoma drugs in pregnant women by trimester?
IOP usually decreases in the 2nd and 3rd trimesters due to hormonal effects Initial high IOP is acceptable
89
Are dilating drops safe to use in pregnant women?
Yesd
90
True or false | All drugs secrete into breast milk with potential for side effects.
True
91
If a mother is taking b-blockers while lactating, what must be done?
Child's pulse must be monitored for bradycardia