Review of Pharmacology - 9E (2015)

Review of Pharmacology
Drugs used in glaucoma
Autonomic Nervous System
Group Drugs Mechanism Adverse effect Special points
1. Miotics
– Directly acting
muscarinic agonist
– AChE inhibitor
2. BETA Blockers
– Non-selective
(β 1
+β 2
) blockers
– Cardioselective
(β 1
) blockers
Pilocarpine
Physostigmine
Echothiophate
Timolol
levobunolol
carteolol Metipranolol
Betaxolol
3. PGF 2α
ANALOGS Latanoprost
Bimatoprost
Travoprost
Tafluprost
Unoprostone
4. α 2
AGONISTS Apraclonidine
Brimonidine
5. α 1
AGONISTS Dipivefrine
Adrenaline
6. Carbonic
anhydrase
inhibitors
Dorzolamide
Brinzolamide
Increase trabecular
outflow
↓ Formation of
aqueous humor
↑ Uveoscleral outflow
↓ Aqueous formation
↑ trabecular and
uveoscleral outflow
↓ Aqueous formation
• Blurred vision due to
induced myopia
• Headache and brow
pain
• AchE inhibitors can lead
to cataract formation
• Allergic blepharoconjunctivitis
• Precipitates asthma
• Transient stinging and
burning in eye
• Iris pigmentation
• Growth of eyelashes
• Macular edema in
aphakics (Latanoprost)
• Reactivation of uveitis
(Latanoprost)
• Lid retraction
• Dry Mouth
• Ocular burning and
allergic conjunctivitis
• Conjunctival hyperemia
(Red Eye)
• Ocular allergy
• Ocular allergy
• Corneal edema
• Bitter taste
• Pilocarpine is short
acting and can result in
fluctuations in IOP
• Miotics increase the risk of
retinal tears in susceptible
individuals
• Can cause punctal
stenosis of nasolacrimal
system
• Should be avoided in:
– Asthma
– Bradycardia
– CHF
– Diabetes
• Betaxolol is less likely to
precipitate asthma but is
less efficacious
• Drug of choice for POAG
• Brimonidine is less likely
to cause ocular allergy
• These can cause CNS
depression and apnea in
neonates and are contraindicated
in children
< 2 years
Anticholinergic Drugs
These drugs act by blocking muscarinic (antimuscarinic) or nicotinic receptors. Drugs blocking
N M
receptors are called neuromuscular blocking agents and those blocking N N
receptors are
called ganglion blockers.
Atropine (obtained from Atropa belladonna) and scopolamine (l-hyoscine) are natural alkaloids
that act as non-selective antagonists at all muscarinic receptors.
Actions of Antimuscarinic agents
62
Triopicamide is the shortest
acting mydriatic.
Central Nervous System
• Atropine is a CNS stimulant whereas scopolamine causes CNS depression.
––
Due to its amnesic and CNS depressant action, hyoscine induces “twilight
sleep” and has been used as a lie detector or truth serum in suspects.
––
Transdermal patch of scopolamine (applied behind the pinna) is used for
prevention of motion sickness.
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