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Mydriatics
Mydriatic drugs work by blocking the muscarinic M3 receptors in the iris sphincter muscle and ciliary muscles, causing pupil dilation (mydriasis) and relaxation of accommodation (cycloplegia). Topical instillation in the eye results in mydriasis, abolition of the light reflex, and cycloplegia. Atropine is the most potent mydriatic drug, with slow onset but long duration of action lasting up to a week. Homatropine is less potent than atropine. Cyclopentolate has a more rapid onset of action but shorter duration of around one day, making it preferred for cycloplegia. Tropicamide has the quickest and brief
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Mydriatics
- 1. MYDRIATIC S ByDr Ketan Asawalle
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- 3. Large pupils wereconsidered a sign of beauty to instil drops of BELLADONNA extract active ingredient of Belladonna is ATROPINE
- 4. INTRODUCTION Classified underANTICHOLINERGIC • Prototype drug- ATROPINE
- 5. muscle of theiris due to decrease in light DEFINITION
- 6. PARASYMPATHETIC SYMPATHETIC RECEPTORSINVOLVED = MUSCARINIC M3 and ADRENERGIC
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- 8. RECEPTORS Pupillary dilators- Alpha 1 receptors Pupillary constrictors - M3 receptors Ciliary muscles M3 receptors
- 9. of Action mainlythrough blocking MUSCARINIC Alpha 1 Adrenergic Agonists also cause mydriasis
- 10. TOPICAL INSTILLATION INEYE CAUSES • MYDRIASIS • ABOLITION OF LIGHT REFLEX • CYCLOPLEGIA
- 11. RESULTS • PHOTOPHOBIA • BLURRING OF VISION
- 12. USES pupil forthe purpose of facilitating ophthalmoscopic its normal position when already prolapsed
- 13. USES ciliary muscle,and thus destroy the power of condition of the refractive media of the eye in cases Spasm of the ciliary muscle Unable voluntarily to relax the accommodation
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- 15. ATROPINE • PotentMydriatic • Slow Onset of Action • Long Lasting
- 16. ATROPINE • Pupilsdilate in 30 to 40 minutes • Cycloplegia lasts for 1 to 3 hours • Effect lasts for 1 week
- 17. HOMATROPINE • Lesspotent • Onset of Action in 30 to 45 minutes • Mydriasis lasts for 1 to 3 days • Accommodation recovers in 1 to 2 days • Unsatisfactory cycloplegia
- 18. CYCLOPENTOLATE • RapidlyActing • Onset of action for Mydriasis Cycloplegia 30 to 60 minutes • Action lasts for 1 day • Preferred for Cycloplegia
- 19. CYCLOPENTOLATE behavioural abnormalitiesdue to absorption though • Uveitis • Iritis
- 20. TROPICAMIDE • QUICKESTand BRIEFEST Satisfactory for refraction testing and fundoscopy Action can be augmented by adding phenylephrine • Unreliable Cycloplegic
- 21. PHENYLEPHRINE • Usedin combination with Tropicamide • Alpha 1 Adrenergic Agonist ciliary muscles to cause mydriasis but NO CYCLOPLEGIA
- 22. LIGNOCAINE and PROPARACAINE • Local anaesthetics • Used in combination with Tropicamide • Used during cataract surgeries • Mechanism of action UNDER RESEARCH
- 23.