Levosalbutamol is the (R)-enantiomer of the racemic drug salbutamol. It is a selective, short-acting beta-2 adrenergic receptor agonist (SABA) used as a bronchodilator for the relief and prevention of bronchospasm. In the Indian context, it is widely prescribed for reversible obstructive airway diseases. It offers a potentially improved therapeutic index over racemic salbutamol, with similar efficacy but a lower incidence of side effects like tachycardia and tremor, as the (S)-enantiomer is considered pharmacologically inactive and may contribute to adverse effects.
Adult: For relief of acute symptoms: 50-100 mcg (1-2 puffs) by MDI as needed, not to exceed recommended maximum. For prevention: 50-100 mcg (1-2 puffs) 15-20 minutes before exercise or allergen exposure.
Note: Shake inhaler well before use. Exhale fully. Place mouthpiece in mouth, seal lips around it. Start to inhale slowly and deeply, then press the canister to release medication. Continue to inhale deeply. Hold breath for about 10 seconds, then exhale slowly. Wait at least 30-60 seconds before second puff. Rinse mouth with water after use to prevent oral thrush. For spacer use, attach spacer to MDI, press canister once, inhale slowly from spacer, hold breath.
Levosalbutamol selectively stimulates intracellular adenyl cyclase, the enzyme that catalyzes the conversion of adenosine triphosphate (ATP) to cyclic-3',5'-adenosine monophosphate (cAMP). Increased cAMP levels trigger a cascade leading to relaxation of bronchial smooth muscle.
Pregnancy: Pregnancy Category C (US FDA). Animal studies show risk; human data limited. Use only if potential benefit justifies potential risk to the fetus. Required for control of asthma, as uncontrolled asthma poses a greater risk.
Driving: May cause dizziness, nervousness, or tremor. Patients should assess their individual response before driving or operating machinery.
| Non-selective Beta-blockers (e.g., Propranolol) | Antagonize bronchodilator effect; may cause severe bronchospasm in asthmatics. | Major |
| Diuretics (e.g., Furosemide, Hydrochlorothiazide) | Enhanced risk of hypokalemia due to additive effect. | Moderate |
| Digoxin | Hypokalemia may increase risk of digoxin toxicity (arrhythmias). | Moderate |
| Monoamine Oxidase Inhibitors (MAOIs) & Tricyclic Antidepressants (TCAs) | May potentiate cardiovascular effects (tachycardia, hypertension). | Moderate |
| Other Sympathomimetics (e.g., Decongestants) | Additive cardiovascular side effects (tachycardia, hypertension). | Moderate |
| Xanthine derivatives (e.g., Theophylline) | Increased risk of hypokalemia and potential additive cardiac effects. | Moderate |
Same composition (Levosalbutamol (50mcg)), different brands: