Bronchodilator · Hyperkalemia treatment
Albuterol
Indications
- Acute bronchospasm in asthma and COPD exacerbations, intermittent or continuous
- Bronchospasm in ventilated or anesthetized patients, by in-line MDI or nebulizer
- Hyperkalemia, as an add-on that shifts potassium into cells (off-label)
- Bronchospasm in anaphylaxis that persists after IM epinephrine (off-label)
Dosing
| Where | Dose |
|---|---|
| Metabolic and electrolyte boluses | Albuterol: 10–20 mg nebulized |
On the quick cards
Mechanism of action
Albuterol is a selective β2-adrenergic agonist, a partial agonist with less intrinsic efficacy than epinephrine. Receptor binding activates Gs, adenylyl cyclase and cAMP; protein kinase A then inhibits myosin light-chain kinase, lowers intracellular calcium and opens calcium-activated potassium channels, relaxing airway smooth muscle from the trachea to the terminal bronchioles. The same cAMP signal stimulates Na⁺/K⁺-ATPase in skeletal muscle, pushing potassium into cells, and drives glycogenolysis and glycolysis, raising glucose and lactate.
Pharmacology
- Respiratory: bronchodilation within minutes; PaO₂ can dip briefly as pulmonary vasodilation worsens V/Q matching
- Cardiovascular: tachycardia from cardiac β2 receptors, β1 at high doses and reflex vasodilation; T-wave flattening, QTc prolongation and ST depression (label)
- Metabolic: potassium falls by 30 min and stays down at least 2 h (10 and 20 mg nebulized lowered it 0.62 and 0.98 mEq/L, Allon 1989); glucose and lactate rise
- Neuromuscular: fine tremor (20% in label trials) and nervousness
Pharmacokinetics
| Onset | Inhaled: within 5 min |
|---|---|
| Peak | About 1 h |
| Duration | 3–4 h, up to 6 h |
| Half-life | 4–6 h (4.6 h inhaled; 3.9 h IV) |
| Distribution | Vd about 2 L/kg; under 20% of a nebulized dose is absorbed, the rest staying in the device or exhaled |
| Protein binding | About 10% |
| Metabolism | SULT1A3 sulfation in gut wall and liver to an inactive sulfate, no CYP; R-albuterol is sulfated faster, so S-albuterol accumulates |
| Elimination | Urine: after IV, 64% unchanged and 12% as sulfate (Morgan 1986) |
| Bioavailability | Oral 50% after first-pass sulfation |
Chemistry
- A saligenin (2-hydroxymethylphenol) ring replaces the catechol, so COMT cannot inactivate it; the bulky tert-butyl amine gives β2 selectivity and resists MAO
- Racemic: R-albuterol (levalbuterol) has about 100 times the β2 affinity of the S-isomer, but pure levalbuterol has not proved clinically better
- pKa values about 9.3 and 10.3: the amine is almost fully protonated at pH 7.4, so it is hydrophilic
- MDI 90 mcg base (108 mcg sulfate) per puff; nebulizer 2.5 mg/3 mL or 0.5% (5 mg/mL) concentrate for continuous use, pH 3–5; protect from light
Adverse effects and cautions
In the one-pagers
- Asthma and COPD ExacerbationsSevere asthma: Albuterol, repeated or continuous, plus ipratropium
- EMT Drugs List: Medications EMTs Can GiveEMT drugs list at a glance: Under the National EMS Scope of Practice Model, EMTs can give oxygen, oral glucose, aspirin and naloxone, use an epinephrine auto-injector, give inhaled albuterol and ipratropium, and help a patient take their own nitroglycerin. Your state sets the final list and your medical director sets the protocol, so learn the national list for the exam and follow local protocol o
- Toxins, Stings and Anaphylaxis in the FieldHidden or delayed drug toxicity: Timolol eye drops: New wheeze, slow pulse: Absorbed systemically: albuterol plus ipratropium; report the drops
- Cardiorespiratory Look-Alikes and Special PatientsAccess and fluids: shock and crush: Watch the monitor at release: peaked T, wide QRS, lost P waves: calcium, bicarbonate, albuterol 5 mg.
- Electrolyte ImbalancesHyperkalemia: stabilize, shift, remove: Add-on shift: nebulized albuterol 10–20 mg, never alone. Bicarbonate mainly for metabolic acidosis.
- Pediatric Assessment and EmergenciesCroup, epiglottitis, bronchiolitis: Bronchiolitis: no routine albuterol or steroids
Practice Asthma and COPD Exacerbations questions free10 exam-style questions with rationales on the topic where Albuterol comes up most. No account or download needed.
In the algorithms
Other bronchodilator drugs
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Sources
- FDA label: Ventolin HFA (2024)
- FDA label: albuterol inhalation solution 0.5%, Ritedose (2026)
- Morgan 1986 (IV and oral kinetics)
- Allon 1989 (hyperkalemia)
For education and exam preparation only. Follow your institution’s protocols. Typical adult values for study. Follow your local protocols and medical direction.