Salbutamol: Drug Effects, Side Effects, Dosage and Uses

Products

Salbutamol is commercially available as a metered-dose inhaler, inhalation solution, diskus, syrup, infusion concentrate, and solution for injection (Ventolin, generics). It has been approved in many countries since 1972 and is also known as albuterol in English-speaking countries. Salbutamol is the precursor of salmeterol and vilanterol (all GlaxoSmithKline).

Structure and properties

Salbutamol (C13H21NO3, Mr = 239.3 g/mol) is present in drugs as salbutamol sulfate, a white crystalline powder that is readily soluble in water, unlike the free base. Salbutamol is a racemate, with the -enantiomer, known as levosalbutamol (levalbuterol), considered more potent. Levalbuterol is marketed separately in some countries (e.g., Xopenex). Salbuterol is a saligenin derivative and structurally related to epinephrine and other beta2-sympathomimetics.

Effects

Salbutamol (ATC R03AC02) has sympathomimetic and bronchodilator (bronchospasmolytic) properties. The effects are due to selective stimulation of adrenergic β2 receptors of the bronchial musculature. The effect occurs rapidly within approximately five minutes after inhalation. Therefore, salbutamol is also suitable for the treatment of an asthma attack. However, the effect lasts only for a short time, about 4 hours. Other beta2-sympathomimetics, such as salmeterol or indacaterol, have a much longer duration of action.

Indications

  • Bronchial asthma, exertional asthma.
  • Acute bronchospasm
  • Chronic bronchitis
  • Treatment of preterm labor in the last trimester of pregnancy (labor inhibitors).
  • Hyperkalemia (off-label)

Dosage

According to the drug label. The drug is usually inhaled three to four times a day.

Abuse

Salbutamol may be abused as a doping agent because of its bronchodilator and anabolic properties. There is a conditional approval for inhaled use. The other methods of application (intravenous, subcutaneous, peroral and intramuscular) are prohibited. See also under clenbuterol as well as under drug overuse.

Contraindication

For complete precautions, see the drug label.

Interactions

Drug-drug interactions have been described with nonselective beta blockers, sympathomimetics, methylxanthines, MAO inhibitors, tricyclic antidepressants, levodopa, levothyroxine, oxytocin, alcohol, cardiac glycosides, quinidine, antiarrhythmics, diuretics, glucocorticoids, ipratropium bromide, nifedipine, halogenated hydrocarbons, and antidiabetics.

Adverse effects

The most common possible adverse effects include tremor, headache, muscle cramps, palpable heartbeats, rapid pulse, and irritation of the oral and pharyngeal mucosa.