Drugs Used In Opthalmology

Question 1

Phenylephrine

Answer 1

• Mechanism of Action: Direct-acting alpha-1 adrenergic agonist, causing mydriasis (pupil dilation).
• Indications:
• Pupil dilation for diagnostic purposes
• Subacute or chronic angle closure glaucoma (ACG) after iridectomy
• Refused surgery cases
• Contraindications:
• Narrow-angle glaucoma
• Hypertension
• Type 1 diabetes mellitus
• Aneurysms
• Cardiac diseases
• Patients on reserpine
• Infants
• Adverse Effects:
• Mild stinging
• Hypertension
• Headache
• Browache
• Dosage: 1 or 2 drops for each refraction.

Question 2

Atropine

Answer 2

• Mechanism of Action: Anticholinergic, blocking the muscarinic action of acetylcholine, causing both mydriasis and cycloplegia (paralysis of accommodation).
• Indications:
• Mydriasis and cycloplegia
• Pupil dilation in inflammatory conditions of the iris
• Amblyopia therapy
• Contraindications:
• Primary (1°) glaucoma
• Hypersensitivity
• Adverse Effects:
• Allergic responses
• Blurred vision
• Photophobia
• Dryness of skin and mouth
• Skin rash
• Dosage: 1 or 2 drops of 0.5% solution in each eye, twice daily for 1 to 3 days prior to examination.

Question 3

Ganciclovir

Answer 3

• Mechanism of Action: Antiviral drug that inhibits viral DNA polymerase, specifically against cytomegalovirus (CMV).
• Indications:
• CMV retinitis (10-25 times more effective than Acyclovir)
• Progressive outer retinal necrosis
• Contraindications:
• Pregnancy
• Hypersensitivity
• Adverse Effects:
• Myelosuppression
• Nephrotoxicity
• Elevation of liver enzymes
• Dosage:
• Oral: 10 mg/kg body weight/dose, 4-5 times daily
• Intravenous: 5 mg/kg over 1 hour, every 12 hours for 14-21 days
• Intravitreal: 2000-400 µg/0.1 mL

Question 4

Natamycin

Answer 4

• Mechanism of Action: Antifungal drug that binds to sterols in fungal cell membranes, causing cell death.
• Indications:
• Fungal blepharitis
• Conjunctivitis
• Keratitis
• Contraindications: Hypersensitivity
• Adverse Effects:
• Conjunctival chemosis
• Hyperemia
• Allergic reactions
• Dosage: 1 drop hourly or 2-hourly intervals for 14-21 days.

Question 5

Flurbiprofen Sodium