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Albuterol Toxicosis 43

hypokalemia is common; hypophosphatemia Drug Interactions
Clinical Presentation is possible. Propranolol: do not use if the patient is hyper-
HISTORY, CHIEF COMPLAINT
VetBooks.ir • Direct observation or evidence of exposure • Blood pressure: hypo- or hypertension tensive. It could worsen the effects by blocking Diseases and Disorders
beta-2 receptors responsible for vasodilation,
possible
resulting in alpha-receptor dominance and
• Electrocardiogram (ECG): premature ven-
(chewed inhaler)
• Acute onset of panting, vomiting, anxiety,
common
tremors, weakness, lethargy tricular complexes/ventricular tachycardia vasoconstriction.
Possible Complications
PHYSICAL EXAM FINDINGS Advanced or Confirmatory Testing • Ventricular premature complexes (VPCs),
• Tachycardia +/− arrhythmia Monitoring cardiac troponin-I concentra- myocardial ischemia/damage or fibrosis
• Tachypnea tion may be helpful to assess myocardial • Kidney injury from prolonged hypotension
• Agitation, tremors, weakness damage. or hypertension
• Rebound hyperkalemia from excessive potas-
Etiology and Pathophysiology TREATMENT sium supplementation
• Albuterol is available in the form of inhal- • Thermal injury to tissues from puncturing
ers (aerosolized powder or liquid), syrups, Treatment Overview pressurized inhalers
injectables, and tablets (prompt release and • Manage tachycardia with beta blockade (if
extended release). required based on rapid sinus tachycardia) Recommended Monitoring
• At therapeutic doses: albuterol binds to and/or correction of hypokalemia (if ven- • Heart rate, blood pressure, ECG
beta-2 receptors on the surface of bron- tricular tachycardia). • Monitor for tremors, seizures, weakness
chial smooth muscles. Cyclic adenosine ○ Potassium supplementation may be • Serum potassium and phosphorus levels
monophosphate (cAMP) increases, leading needed, but avoid rebound hyperkalemia
to relaxation of bronchial muscle cells and from over-supplementation: monitor and PROGNOSIS & OUTCOME
bronchodilation. adjust (p. 516).
• In overdoses, beta-2 receptor selectivity is • Monitor for and manage arrhythmias • Excellent with prompt and correct treatment
lost, resulting in excessive beta-1 and beta-2 (p. 1033). of cardiac arrhythmias
activity. • Manage tremors/stimulatory signs, if present, • Development of arrhythmias and
○ Beta-2 effects: hypotension, reflex sinus with benzodiazepines (p. 994). cardiac damage is more common with
tachycardia, arrhythmias; tremors from • Decontamination (emesis and activated delayed treatment and could worsen
stimulation of receptors in skeletal charcoal) is not indicated with ingestions prognosis.
muscles; vomiting; intracellular shifting of liquids, syrups, or inhalation forms
of potassium and phosphorus secondary to of albuterol due to its rapid absorption. PEARLS & CONSIDERATIONS
increased adenosine triphosphate enzymes Consider emesis with 3% hydrogen peroxide
(ATPases), and respiratory alkalosis from or apomorphine in asymptomatic dogs that Comments
panting have ingested tablets (p. 1188) and are • All albuterol exposures should be taken
○ Beta-1 effects and catecholamine release: asymptomatic. seriously, and the patient should be evaluated
positive inotropic effects on the heart, • Intravenous (IV) fluid support; adjust fluid quickly.
tachycardia, hypertension, restlessness, rate cautiously in patients that already have • Signs can develop even if the prescriptions
anxiety cardiac arrhythmias or hypertension. are old/expired or from exposures to seem-
○ Arrhythmias can also occur from secondary ingly empty inhalers.
myocardial damage and hypokalemia. Acute General Treatment • Dogs biting into the inhaler can often receive
Aerosolized inhalers often contain hydro- • Propranolol (if normotensive) 0.02 mg/kg a large dose of albuterol orally at once when
carbons as the propellant, which can IV. If hypertensive, use esmolol: loading pressured aerosol inhalers are punctured,
sensitize the myocardium and increase risk dose of 0.25-0.5 mg/kg (250-500 mcg/ leading to rapid onset of clinical signs within
for arrhythmias. kg) slow IV over 2-5 minutes, followed minutes to a few hours.
○ Hypokalemia and prolonged tachycardia by a constant rate infusion (CRI) of 10- • Clinical signs and hypokalemia/hypophos-
are often the causes for weakness. 200 mcg/kg/min. phatemia associated with albuterol toxicosis
• Correct hypokalemia (p. 516). may take 12-48 hours before completely
DIAGNOSIS ○ Hypokalemia favors ventricular arrhyth- returning to normal.
mias and makes the myocardium refrac- • Profound muscle weakness or collapse
Diagnostic Overview tory to lidocaine and other class I in dogs seen within a few hours of
Evidence of exposure (therapeutic or accidental) antiarrhythmics. albuterol exposure correlates well with
and presence of characteristic clinical signs ○ Correction of hypokalemia improves/ severe hypokalemia. Muscle weakness
(panting, tachycardia) establish the clinical resolves ventricular arrhythmias while also resolves when fluids are supplemented
diagnosis. Hypokalemia and/or hypophospha- helping reduce or eliminate muscular with potassium chloride or potassium
temia offer further support. weakness and lethargy. phosphate.
• Lidocaine (for ventricular arrhythmia, only
Differential Diagnosis if normokalemic, p. 1457): 2-8 mg/kg slow Prevention
• Toxicologic: pseudoephedrine, amphet- IV over 1-2 min, followed by a CRI of • Keep medications out of reach of pets.
amines, selective serotonin reuptake inhibi- 25-80 mcg/kg/min • Properly dose animals that are being treated
tors (p. 1281), calcium channel blockers, • Potassium chloride (if potassium is with albuterol.
cardiac glycosides < 3 mEq/L)
• Non-toxicologic: hypovolemic shock, car- • Potassium phosphate (if potassium is Technician Tips
diogenic shock, septic shock, neoplasia < 3 mEq/L and phosphorus is < 1 mg/dL): • Monitor the ECG and know how to recog-
0.01-0.06 mmol/kg/h IV mixed in saline or nize cardiac arrhythmias.
Initial Database dextrose • Ask the client if the albuterol inhaler
• Complete blood count (CBC), serum bio- • For agitation/anxiety: diazepam 0.5 mg/kg punctured by the dog was used or relatively
chemistry profile: mild to severe/critical IV or midazolam 0.2-0.4 mg/kg IV or IM new.

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