There are a number of adverse reactions to salbutamol that have been encountered during its 20 years of use. In general, these side effects of salbutamol are dose-related and occur more frequently with the oral tablets or syrup than with the inhalation aerosol or nebulizers.
The most common adverse reactions associated with use of salbutamol inhalation aerosol are palpitations (occurring in less than 10% of patients), sinus tachycardia (less than 10%), anxiety (less than 10%), tremors (less than 15% of patients) and increased blood pressure (approximately 5%), occasionally resulting in hypertension. Other side effects include nausea and vomiting (6%), throat irritation (6%), dyspepsia (5%), insomnia (3%), heachaches (3%), epistaxis (3%), cough (2%), dizziness (1%), nightmares (1%), and hostility (1%). Some cases of urticaria, angioedema, maculopapular rash, bronchospasm, hoarseness, and oropharyngeal edema have also been reported after use of inhaled salbutamol. Salbutamol nebulizers produce adverse effects similar to those observed with the inhalation aerosol.
The most common adverse reactions to salbutamol tablets or syrup are tremors (occurring in 10-20% of patients) and anxiety (9-20%). Other reported adverse reactions include headaches (4-7%), sinus tachycardia and palpitations (2-5%), hyperkinesis (2-4%), dizziness (2-3%), muscle cramps (1-3%), insomnia (1-2%), nausea/vomiting (1-4%), and excitability (2%). The use of extended-release tablets has been found to lower the incidence of adverse reactions, although not stopping them completely. Less frequent adverse reactions occurring in less than 1% of patients include flushing, drowsiness, restlessness, irritability, angina, cough, diaphoresis, and urinary retention.
Often, adverse reactions occur in young children of 2-6 years of age than in older children or adults, particularly excitability and anxiety, which occur in roughly 20% and 15% of young children respectively. Gastrointestinal problems such as nausea and vomiting have been reported in about 2% of young children who use salbutamol.
As a adrenoceptor agonist, salbutamol can in a small number of cases induce adverse cardiovascular effects such as hypertension ( in 3% of patients), angina ( in less than 1%), or arrhythmia exacerbation or precipitation, particularly in patients already suffering from some form of cardiovascular disease.
Salbutamol can also induce hyperglycemia and hypokalemia. Both of these effects occur due to stimulation of beta2-receptors, resulting in gluconeogenesis and intracellular movement of potassium. These effects occur most commonly with inhalation through nebulizers of relatively large doses of salbutamol , such as over 5 mg.