Inhaled Albuterol (Salbutamol) Pharmacologic Effects
Inhaled albuterol produces bronchodilation by activating β2-adrenergic receptors in bronchial smooth muscle. [1] Inhaled albuterol also produces systemic sympathomimetic effects that can include tremor, tachycardia, palpitations, and hypokalemia. [1]
Primary Therapeutic Effect: Airway Smooth Muscle Relaxation
β2-adrenergic receptor stimulation increases cyclic AMP in airway smooth muscle, leading to relaxation of bronchial smooth muscle. [3] Clinical inhaled albuterol use is associated with relief of bronchospasm in obstructive airway disease. [3]
Common Systemic Adverse Effects
Tremor and nervousness are commonly reported adverse effects of albuterol. [4] Palpitations and rapid heart rate are commonly reported adverse effects of inhaled albuterol. [1] Chest pain and insomnia have been reported among adverse reactions associated with inhaled albuterol. [1]
Cardiovascular Effects and Arrhythmia Risk
Inhaled and intravenous albuterol can produce adverse cardiovascular effects, with hypokalemia described as a potential contributor. [1] Postmarketing adverse reactions with inhaled albuterol have included arrhythmias, including atrial fibrillation and supraventricular tachycardia. [7] Overdosage signs can include tachycardia with rates up to 200 beats per minute and other tachyarrhythmias. [10]
Serum Potassium Effects (Hypokalemia)
β2-agonists can lower serum potassium by shifting potassium into cells via stimulation of the Na+/K+-ATPase pathway. [2] Inhaled albuterol labeling describes significant hypokalemia in some patients, with a potential for adverse cardiovascular effects. [1]
Metabolic and Neurologic Effects
Albuterol has been associated with hyperglycemia among sympathomimetic adverse reactions. [7] Albuterol can cause central nervous system stimulation, including headache and nervousness. [7] Albuterol can also be associated with metabolic acidosis among sympathomimetic adverse reactions. [7]
Important Overdose and Drug Interaction Considerations
Overdosage produces features of excessive β-adrenergic stimulation, including hypertension or hypotension, tremor, seizures, and tachycardia. [10] The ECG changes and/or hypokalemia that can result from non–potassium-sparing diuretics may be acutely worsened by β-agonists when doses exceed recommended dosing. [1]
Practical Clinical Safety Signals
Urgent medical evaluation is indicated for symptoms consistent with significant tachycardia, arrhythmia, chest pain, or seizures following albuterol exposure. [10] Urgent medical evaluation is indicated when severe weakness or abnormal heart symptoms occur after repeated or high-dose inhaled albuterol due to the risk of hypokalemia and cardiovascular effects. [1]
Discontinuation or Adjustment Considerations
Albuterol is not a substitute for controller therapy in chronic asthma or chronic obstructive pulmonary disease when such therapy is indicated. [4]