Give me answer from harrison. What is the best drug for angle closure glaucoma
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acute angle closure glaucoma pilocarpine acetazolamide timolol treatment Harrison's
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Here is the answer directly from Harrison's Principles of Internal Medicine, 21st Edition (p. 952):
Treatment of Acute Angle-Closure Glaucoma
According to Harrison's, there is no single "best" drug — acute angle closure is treated with a combination of agents targeting different mechanisms simultaneously:
| Drug | Class | Mechanism |
|---|---|---|
| Acetazolamide (PO or IV) | Carbonic anhydrase inhibitor | Reduces aqueous humor production |
| Topical beta-blockers (e.g., timolol) | β-adrenergic antagonist | Reduces aqueous humor production |
| Prostaglandin analogues (e.g., latanoprost) | Prostaglandin | Increases aqueous outflow |
| α₂-adrenergic agonists (e.g., brimonidine) | Alpha-2 agonist | Reduces aqueous production & increases outflow |
| Pilocarpine | Cholinergic miotic | Induces miosis, opens drainage angle |
Key Points from Harrison's:
- Acetazolamide (oral or IV) is the cornerstone systemic agent and acts rapidly to lower IOP by reducing aqueous humor secretion.
- Pilocarpine is the classic miotic used to pull the iris away from the trabecular meshwork by constricting the pupil, directly relieving pupillary block — it is the most mechanism-specific drug for angle closure.
- If medical therapy fails, laser peripheral iridotomy (LPI) is performed to create a hole in the peripheral iris, definitively relieving pupillary block.
Clinical Note:
Harrison's also notes that the risk of precipitating angle closure with routine pharmacologic pupil dilation is "actually remote" and is outweighed by the diagnostic benefit — a single induced attack rarely causes permanent damage and can serve as an inadvertent provocative test.
In summary, if one drug must be highlighted, acetazolamide (systemic, rapid IOP reduction) combined with pilocarpine (miosis to open the angle) forms the pharmacologic backbone of acute angle-closure management per Harrison's.
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