Anti-glaucoma drugs Flashcards
What is dependent on how glaucoma is treated?
The age of onset and the rate of progression
What is a huge risk factor of glaucoma?
Ocular hyper tension (they have a raised IOP but normal disc and fields)
In a forest plot, what does the vertical line down the middle indicate?
Line of no difference
Is there evidence to suggest that if you treat patients with ocular hypertension then you reduce the odds of visual field progression?
Yes- A meta analysis shows a 38% reduction in odds
What is latanoprost?
A prostaglandin which lowers IOP in treating px with open angle glaucoma
Is there a target IOP for glaucoma/ at risk glaucoma pxs?
No- there is not a single target, it is individually taking into account baseline iop, age of onset and determining what will cause slowest rate of progression
On average what percentage of mmHg is the target IOP we try to reduce the IOP by?
20-35%–> 5-7mmHg
What factors are taken to determine the target IOP?
- Rate of progression
- Early onset glaucoma
- Long life expectancy
- Late presenting glaucoma
- Status of other eye
What is the drug of first choice for glaucoma treatment?
Prostaglandins
If the first line treatment of prostaglandins are well tolerated and effective on lowering IOPs, then what happens next?
Px maintained on therapy, evaluated periodically to assess vision loss, optic disc status, IOPs and quality of life
If the first line treatment of prostaglandins is not effective in lowering IOPs then what happens?
Substitute for a second drug or additionally a second drug is added or other therapeutic options are considered
How does the LiGHT trial work in order to lower IOPs?
Laser trabecular plasticity- the laser is directed at the trabecular mesh work to open it up and lower resistance to outflow for primary open angle glaucoma
What was significant about the LiGHT trial?
It could be more cost effective first-line open angle glaucoma and ocular hypertension treatment in lowering IOPs
Are majority of drugs used to treatment glaucoma topical or systemic?
Topical
Name the five classes of topical drugs
1) Prostaglandins
2) Beta receptor antagonists
3) Alpha 2 receptor agonists
4) Carbonic anhydrase inhibitors
5) Cholingeric agonists
Which of the five classes of topical drugs is less widely used?
Cholingeric agonists
Give an example of a cholingeric agonist?
Pilocarpine
Give an example of a beta blocker anatagonist that was used in 1978
Timolol
Give an example of a topical carbonic anhydrase inhibitor?
Dorzolamide
What is the first prostaglandin to be used?
Latanoprost
What is the mechanism of action of topical drugs? (3 ways)
- Reduce aqueous production
- Increase outflow through trabecular meshwork
- Increase uveoscleral flow
Which class of drugs reduce aqueous production?
Alpha agonists, beta blockers and carbonic anhydrase inhibitors
Which class of drugs increase outflow through trabecular meshwork?
Cholingerics
Which class of drug increase uveoscleral flow?
Prostaglandins
In which type of glaucoma would drugs be issues systemically and which drugs would be issues?
Acute angle closure
Carbonic anhydrase inhibitors
Osmotic agents
Give an example of an carbonic anhydrase inhibitor
Acetazolamide (Diamox)
Give an example of an osmotic agent
Glycerol, mannitol
Before prescribing any new eye drop for glaucoma, what four things must you consider ?
- General medical history (factors which may increase risk of someone developing adverse effects)
- Drug history (any interactions)
- History of topical allergy
- Can the px use eye drops (memory and dexterity)
What four points must you consider when CHOOSING a drug?
- Efficacy (in lowering IOP)
- Safety (which is the most appropriate drug fo this px)
- Compliance (ensuring the px is taking the medication)
- Cost
Name the order high to lowest efficacy of glaucoma drugs
Prostaglandins agonists, beta blocker antagonists, alpha 2 agonists, cholingeric agonists, carnbonic anhydrase inhibitors
What do the prostaglandin drugs end in?
Prost
Name four prostaglandins
Latanoprost and travoprost and tafluprost and bimatoprost (prostamide)
What is the trade name of latanoprost
Xalatan
What is a side effect of prostaglandins?
Conjunctival hyperaemia (latanoprost is least likely for this to happen)
Darkening, thickening and lengthening of eye lashes
Increased iris pigmentation (affects px with light brown/ hazel eyes- not really the other colours)
Name three beta-antagonist
Timolol maleate (non-selective) , betaxolol (selective) and levobunolol
What is a side effect of beta- antagonists and why?
Can cause bronchoconstrition especially in patients with obstructive airways disease or asthma
- because lungs have beta 2 receptors and stimulating or blocking these receptors causes bronchoconstriction
What dosage of timolol is normally prescribed with a prostaglandin or carbonic anhydrase inhibitor?
Timolol 0.5%
What conditions normally co-exist with glaucoma?
Airways disease- SO IMPORTANT TO MENTION THIS IN HISTORY
Why is excluding airway disease so important when prescribing beta blockers when taking history?
It can cause bronchoconstriction and there is a relationship between usage of topical beta antagonists and new use/ increased use of bronchodilators
What must you ask about/ do before prescribing beta antagonsits?
*there are five
- Ask about COAD (chronic obstructive airways disease)/ SOBOE (shortness of breath on exertion)/ inhaler usage
-Check peak flow - Check pulse
- Consider drug interactions
- Recheck peak flow one month after starting treatment
What are the two alpha agonists for glaucoma treatment?
Brimonidine and apraclonidine
How does briminodine work to reduce IOPs?
Increases uveoscleral outflow and reduce aqueous production
When is apraclonidine used?
For post-operative management as a short term therapy to lower IOPs
What are side effects of alpha agonists?
- High incidence of ocular side effects (e.g follicular conjunctivitis)
- High incidence of systemic side effects such as hypotension, dry mouth, headache, anxiety, depression
Name two topical carbonic anhydrase inhibitors
Dorzolamide and brinzolamide
What are carbonic anhydrase inhibitors normally combined with?
Beta blockers
What is an example of an oral carbonic anhydrase inhibitors?
Acetazolamide
What are side effects of TOPICAL carbonic anhydrase inhibitors?
-Metallic taste
- Rashes
- Polyuria (excessive urination)
- Irritation
- Blurred vision
What are side effects of ORAL carbonic anhydrase inhibitors?
- Allergy
- Hypokalemia
- Polyuria
- Acidesis
- Depression
- Parethesia
- Kidney stones
- Blood dyscrasia
Why is cholingergic not used?
Not cost effective and causes misosis, myopia, symblepharon, post synechiae, RD, confusion, vomiting, nausea
What are six points that may influence compliance?
- Simplicity of regime
- Memory
- Manual dexterity
- Understanding of disease
- Topical side effects
- Systemic side effects
Why is cost important to consider?
We want to minimise cost to NHS
If a patient needs more that two drops, then what are other options?
Selective laser trabeculaplastuy and trabeculemtory
