PHARMACOLOGICAL ASPECTS OF OCULAR BETA-BLOCKERS:

Biotechnology
1

Beta blockers are topical drugs used in treating glaucoma. It lowers the production of aqueous humour thereby reducing the intraocular pressure (IOP).Widely used as a primary and combination therapy for glaucoma.

Primarily used in the treatment of Primary Open Angle Glaucoma (POAG).

COMMONLY USED:

  • Timolol

  • Betaxolol

  • Levobutanol

  • Cardio-selective – Metaprolol. Atenolol, bisoprolol.

MECHANISM OF ACTION:

  1. Beta receptors – Widely found in trabecular meshwork, ciliary body, crystalline lens epithelium and in retinal arteries.

  2. Huge amount is accumulated in ciliary body, which responsible for maintaining IOP.

  3. Blockage of the sympathetic nerve endings of the ciliary body epithelium

  4. Reduction in aqueous production.

  5. Lowers IOP

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SIDE EFFECTS:

  1. OCULAR: Stinging, redness, allergic blepharoconjunctivitis and blurred vision.

  2. SYSTEMIC: Should be used in caution with respiratory illness patient.

List out some other actions of beta blockers in systemic usage that you know !

MBH/PS

2

systemic uses of beta blockers can be cardiac and non cardiac:

Cardiovascular

  • Hypertension
  • Chronic stable angina
  • Acute and previous myocardial infarction
  • Heart failure (selected agents: metoprolol, bisoprolol, carvedilol)
  • Supraventricular tachycardia
  • Atrial fibrillation (rate control)
  • Ventricular arrhythmias
  • Aortic dissection (reduce shear stress)

Non-cardiac

  • Hyperthyroidism/thyroid storm (especially propranolol)
  • Essential tremor
  • Migraine prophylaxis
  • Performance anxiety
  • Portal hypertension (prevention of variceal bleeding)
  • Glaucoma (topical timolol)
  • Hypertrophic obstructive cardiomyopathy
  • Pheochromocytoma (only after adequate α-blockade)