Albuterol is a commonly prescribed bronchodilator used for the treatment of asthma. It is most commonly formulated as an aerosol for inhalation, but it is also prescribed as a solution for nebulization, a capsulated powder for inhalation and in tablets for ingestion.
Albuterol, also known as salbutamol, is a potent beta agonist. At therapeutic doses, it selectively binds to beta2 receptors on the surface of smooth muscle cells, such as those in the airways. In overdose situations, it also binds to beta1 receptors in skeletal muscle, liver and cardiac tissue. The beta1 stimulation results in positive inotropic and chronotropic effects on the heart, arrhythmias, tachypnea, agitation, tremors and—rarely—seizures.
The most common way pets are exposed to albuterol is via a punctured inhaler. Once the inhaler is punctured, the drug is almost instantly delivered. The patient is exposed transmucosally and via inhalation and often ingestion.
On presentation, patients suffering from albuterol toxicosis may appear agitated and restless or alternatively lethargic. Some patients may even appear to be very normal until their vital parameters are assessed. Tachycardia, tachypnea, vomiting, hypertension, hypotension and tremors are common.
With exposure to an inhaler or solution, decontamination is not recommended. Induction of emesis and activated charcoal administration may be of benefit with exposure to albuterol pills if the animal is still asymptomatic. Instead of decontamination, the focus of treatment is to control the symptoms of toxicity and prevent cardiovascular decompensation.
Intravenous fluids are recommended for general cardiovascular support and to maintain hydration
Supplement with potassium phosphate or potassium chloride if serum K+ is < 2.5mEq/L
Propranolol is used to treat tachycardia. It is a non-selective beta blocker and is considered a specific antagonist to albuterol
If there is concurrent hypertension, a beta 1 selective beta blocker such as esmolol or metoprolol is recommended
Lidocaine is used to control ventricular arrhythmias
Diazepam is used to control agitation, tremors or seizures
Acepromazine or chlorpromazine can be used to treat agitation with concurrent hypertension
It is recommended to assess serum potassium and phosphorous levels at presentation and again every four to six hours for the first 12 hours in the hospital. Hypokalemia and hypophosphatemia, sometimes severe, are common findings. (It is important to remember that this is from an intracellular shifting of these ions rather than a whole body depletion. Once the patient’s signs are controlled these tend to spontaneously resolve.)
With prompt treatment, the prognosis is excellent and hospitalization is usually 24 to 36 hours. If there is pre-existing cardiac disease, treatment is delayed, or refractory arrhythmias develop, the prognosis is more guarded and hospitalization may be longer.
Assessing serum troponin levels and echocardiography are recommended for severely affected patients.