What is the appropriate salbutamol (albuterol) dose for an adult (≥12 years) presenting with wheeze, including any adjustments for patients over 65 years or with stable cardiac disease?

Salbutamol Dosing for Adult Wheeze

For adults presenting with wheeze, administer 2.5–5 mg salbutamol by nebulizer every 20 minutes for three doses during the first hour, then continue every 1–4 hours as needed based on clinical response. 1, 2

Initial Emergency Treatment (First Hour)

Nebulizer dosing:

• Give 2.5–5 mg salbutamol every 20 minutes for three consecutive doses to achieve maximal bronchodilation during the period of greatest airway constriction 1, 2
• Dilute each dose in at least 3 mL normal saline to ensure optimal aerosol generation 1, 2
• Use oxygen as the driving gas at 6–8 L/min whenever feasible to improve drug delivery and patient oxygenation 1, 2

MDI alternative for mild-to-moderate wheeze:

• Administer 4–8 puffs (360–720 mcg) via MDI with spacer every 20 minutes for three doses as an equally effective alternative when proper technique is used 1, 2
• Each puff of standard albuterol MDI delivers 90 mcg 1, 2

Maintenance Phase (After First Hour)

• Continue salbutamol 2.5–5 mg by nebulizer every 1–4 hours as needed, adjusting frequency based on symptom control and clinical response 1, 2, 3
• Gradually decrease dosing frequency as symptoms improve to prevent overtreatment once airway tone normalizes 2
• The FDA-approved maintenance regimen is 2.5 mg three to four times daily for ongoing bronchospasm control 3

Severe or Life-Threatening Wheeze

For patients with severe respiratory distress or impending respiratory failure:

• Administer continuous nebulization at 10–15 mg/hour for adults not responding to intermittent dosing 2
• Add ipratropium bromide 500 mcg to each of the first three salbutamol doses to enhance bronchodilation in moderate-to-severe presentations 1, 2
• The combination of salbutamol plus ipratropium significantly reduces hospitalization rates in severe exacerbations 2

Special Population Considerations

Patients over 65 years:

• Use the same standard adult dosing (2.5–5 mg); no specific age-based dose reduction is recommended in guidelines 1
• Monitor more closely for tachycardia and tremor, which may be less well-tolerated 1

Patients with stable cardiac disease:

• Standard salbutamol dosing remains appropriate; cardiovascular adverse reactions with inhaled therapy are uncommon 1
• The inhaled route causes fewer systemic adverse effects compared to oral or parenteral routes 1
• Monitor for tachycardia, but this is rarely clinically significant with appropriate dosing 1, 2

COPD patients at risk for CO₂ retention:

• Use compressed air rather than oxygen as the driving gas to avoid worsening hypercapnia 1, 2
• Alternatively, provide monitored oxygen therapy while using an air-driven nebulizer 1

Critical Monitoring and Safety

Watch for these adverse effects:

• Tachycardia, skeletal muscle tremor, hypokalemia, headache, and hyperglycemia 1, 2
• These side effects are generally mild and well-tolerated with inhaled administration 1

Signs requiring escalation of care:

• Inability to speak in complete sentences, altered mental status, intercostal retractions, worsening fatigue, silent chest, or oxygen saturation persistently <90% 1, 2
• Lack of response to repeated nebulized therapy indicates need for senior clinician review and possible intensive care 1

Transition to Discharge Therapy

• Switch to MDI with spacer 24–48 hours before discharge once clinical improvement is demonstrated 1, 2
• Continue nebulizations until peak expiratory flow exceeds 75% of predicted and diurnal variability falls below 25% 1
• Early discharge is facilitated by transitioning to hand-held inhalers as soon as the patient's condition stabilizes 1

Common Pitfalls to Avoid

• Do not underdose in the acute setting—the initial 20-minute interval dosing for three doses is critical for achieving adequate bronchodilation 1, 2
• Do not continue ipratropium beyond the first three doses once hospitalized, as additional benefit has not been demonstrated 2
• Do not substitute MDI for nebulizer in severe exacerbations without evidence of adequate response, as nebulized therapy provides more reliable drug delivery when airways are severely constricted 2
• Increasing use or lack of expected effect indicates diminished control and requires reassessment rather than simply continuing the same regimen 1