Antiadrenergic Drugs And Drugs For Glaucoma Question And Answers

Antiadrenergic Drugs And Drugs For Glaucoma

 

Question 1. Describe The Briefl Role Of Pilocarpine In Glaucoma.
Answer:

Pilocarpine is a cholinergic drug or parasympathomimetic drug. It has prominent muscarinic actions.

Pilocarpine is effective in both types of glaucoma (open-angle as well as closed-angle) though its mechanism in both of them differs:

1. Angle Closure/Narrow-Angle/Acute Congestive Glaucoma: Pilocarpine causes contraction of the sphincter pupillae.

This causes the iris mass to spread centrally and reduces the contact of the iris with the lens.

The iridocorneal angle gets widened and the pupillary block is removed.

2. Open Angle Wide Angle/Chronic Simple Glaucoma: Pilocarpine increases the tone of ciliary muscle attached to the scleral spur and sphincter pupillae.

This improves the alignment of the trabeculae to improve the output of the aqueous humor. The intraocular tension is thus lowered.

Read And Learn More: Pharmacology Question And Answers

 

Question 2. Give A Description Of The Drug For Glaucoma.
Answer:

Glaucoma is a group of diseases characterized by a progressive form of optic nerve damage associated with raised intraocular tension.

Glaucoma is of two types, i.e. acute congestive glaucoma and chronic simple glaucoma.

Drugs Used In Acute Congestive Glaucoma

1. Osmotic agents: 20% mannitol IV, 50% glycerol orally
2. Carbonic anhydrase inhibitors: Acetazolamide IV or orally
3. β blockers: 0.5% timolol topically
4. Mitotic: 2% pilocarpine topically
5. Prostaglandins: 0.005% Latanoprost topically.

Drugs Used In Chronic Simple Glaucoma

1. β blockers: 0.25% timolol, 0.25% betaxolol, 1% carteolol topically.
2. Prostaglandins: 0.005% latanoprost
3. Carbonic anhydrase inhibitors: 2% dorzolamide, brinzolamide topically, and acetazolamide orally
4. α adrenergic antagonists: 0.1% Dipivefrin and 1% apraclonidine topically
5. Mitotic: 0.5% pilocarpine topically.

• Osmotic agents, i.e. Mannitol and 50% glycerol draw fluid from the eye in circulation by osmotic effect and reduce intraocular pressure in acute congestive glaucoma.
• Carbonic anhydrase inhibitors: Acetazolamide inhibits carbonic anhydrase enzyme and decreases intraocular pressure by decreasing the formation of aqueous humor.
  In chronic simple glaucoma, acetazolamide should be given topically while in acute simple glaucoma, it is given as IV and orally.
• β adrenergic blockers: Topical non-selective β blocker is very commonly used in glaucoma because it lacks local anesthetic property; It does not affect the size of the pupil.
  Its duration of action is long; well tolerated and less expensive.
• Prostaglandins: Topical prostaglandins such as latanoprost, travoprost, and bimatoprost are used in initial therapy for open-angle glaucoma as they have a long duration of action.
  High efficacy and cause less systemic toxicity. They decrease intra-ocular pressure by facilitating uveoscleral outflow.
• Mitotic: Pilocarpine is used topically in the treatment of open-angle and acute congestive glaucoma. It causes drainage of aqueous humor and decreases intra-ocular pressure.
• α-adrenergic agonists: Apraclonidine decreases the formation of aqueous humor and decreases the intraocular pressure. Dipivefrine is another drug that penetrates the cornea, converts it into adrenaline, and acts on α1 and α2 and β receptors. When it acts on α1 and α2 receptors it reduces the aqueous secretion and decreases intraocular pressure. When it acts on β receptors, it increases uveoscleral outflow and trabecular outflow which decreases the intraocular pressure.

Question 3. Write Drug Treatment Of Acute Congestive Glaucoma.
Answer:

Following is the drug treatment for acute congestive glaucoma:

• Hypertonic mannitol 20% infused IV decongests the eye by osmotic action.
• Acetazolamide 0.5 gm IV followed by oral twice daily
• Mitotic: As the intraocular tension start falling due to the above IV therapy, pilocarpine 1 to 4% is instilled every 10 min initially and then at longer intervals.
• Topical β blocker: Timolol 0.5% is instilled 12 hours in addition.
• Apraclonidine 1% may be added.