Ipratropium Bromide

Brand Names: Atrovent, Ipratropium Bromide

Drug Class: Anticholinergic bronchodilator, Muscarinic antagonist

Overview

Ipratropium bromide is a quaternary ammonium derivative of atropine that acts as an anticholinergic bronchodilator. It is used primarily for the management of bronchospasm associated with chronic obstructive pulmonary disease (COPD), including chronic bronchitis and emphysema, and sometimes for asthma. Unlike systemic anticholinergics, it has minimal systemic absorption when inhaled, reducing side effects.

Mechanism of Action

Ipratropium bromide is a competitive antagonist of muscarinic acetylcholine receptors (specifically M1, M2, and M3 subtypes) in bronchial smooth muscle. By blocking acetylcholine, it inhibits parasympathetic-mediated bronchoconstriction and mucus secretion, leading to bronchodilation. It does not affect beta-adrenergic receptors.

Indications

  • Maintenance treatment of bronchospasm associated with chronic obstructive pulmonary disease (COPD)
  • Acute exacerbations of bronchospasm in COPD
  • Adjunctive therapy in asthma management (not first-line)
  • Rhinorrhea associated with allergic and non-allergic perennial rhinitis (nasal formulation)

Dosage

For inhalation (aerosol or solution via nebulizer): Adults: 2 inhalations (17-21 mcg per inhalation) four times daily, up to 12 inhalations in 24 hours. Nebulizer solution: 500 mcg (one unit-dose vial) 3-4 times daily. Dosing may vary based on formulation and severity; follow prescribing information. Not for initial relief of acute episodes.

Contraindications

  • Hypersensitivity to ipratropium bromide, atropine, or its derivatives
  • Hypersensitivity to soya lecithin or related food products (e.g., peanuts, soybeans) in aerosol formulations
  • Use in narrow-angle glaucoma (risk of acute exacerbation if aerosol enters eyes)

Side Effects

  • Dry mouth or throat
  • Cough
  • Headache
  • Nausea
  • Dizziness
  • Blurred vision (if eye contact occurs)
  • Palpitations
  • Urinary retention (rare)
  • Paradoxical bronchospasm
  • Allergic reactions (e.g., rash, angioedema)

Interactions

  • Anticholinergic drugs (e.g., tiotropium, aclidinium) may increase anticholinergic side effects
  • Beta-adrenergic agonists (e.g., albuterol) are often used concomitantly for additive bronchodilation
  • No significant pharmacokinetic interactions reported with systemic drugs due to low absorption