A recent article by Johnson DB, Merrell BJ, Bounds CG on Salbutamol talks about its indications, mechanism of action, administration, adverse effects, contraindications, monitoring, toxicity etc. 

They mentioned that Albuterol aka salbutamol is frequently used in patients with reversible obstructive airway disease for the treatment and prevention of acute/ severe bronchospasm. the drug also comes as the choice of medication for asthma and as an adjuvant treatment of hyperkalemia. 

The paper has cited its administration dosages as-

• For bronchospasm- A nebulized solution of 2.5 mg B.D. or T.D.S,
• 1 OR 2 puffs of 90mcg every 4-6 hours of the powdered/aerosol metered-dose inhaler (not to exceed 12 puff each day), 
• 2 to 4 mg every 6 to 8 hours of tablet/syrup (not to exceed 32mg each day).
• For acute or severe bronchospasm- A nebulizer solution of 2.5 to 5 mg every 20 minutes for the 1st 3cycles, followed by 2.5 to 10 mg every 1 to 4 hours SOS, or continuous nebulizer treatments every 10 to 15 minutes,
• 4 - 8 puffs of 90 mcg every 20 minutes for up to 4 hours in a metered-dose inhaler, continued by 4 to 8 puffs every 1 to 4 hours SOS.
• For exercise-induced bronchospasm- 2puffs of 90 mcg of the powdered/aerosol metered-dose inhaler to be taken 15 to 20 minutes before exercise.
• For pediatric patients- 
• 2-0.6 mg/kg/day nebulizer solution divided into either a 4- or 6-hour cycle for children <2years of age,
• 5 mg/0.5 mL nebulizer solution every 6 to 8 hours with a maximum of 10 mg/day for children >2years of age,
• 90 to 180 mcg (1 to 2 puffs) every 4 to 6 hours of aerosol metered-dose inhalers in children >4years of age,
• 180 mcg (2 puffs) of powder metered-dose inhalers every 4 to 6 hours not to exceed 12 puffs/day in children >4years of age,
• 3 to 0.6 mg/kg/day of albuterol tablets divided into 3treatments given every 8 hours throughout the day, not to exceed 12 mg/day, in children <6years of age,
• 2 mg every 6 - 8 hours of albuterol tablet, not to exceed 24 mg per day in children between 6-12 years of age,
• 4 mg every 6 - 8 hours of albuterol tablet, not to exceed 32 mg per day in children >12 years of age,
• 4 mg every 12 hours of Extended-release albuterol tablets not to exceed 24 mg/day in children between 6-12 years of age,
• 8 mg every 12 hours of Extended-release albuterol tablets in children >12 years of age,
• 1-0.2 mg/kg every 8 hours of albuterol syrup in children between 6-12 years of age,
• 2 mg every 6 to 8 hours of albuterol syrup in children between 6-14 years of age,
• 2-4 mg every 6 to 8 hours, not to exceed 32 mg/day of albuterol syrup in children >14 years of age.

Source: Johnson DB, Merrell BJ, Bounds CG. Albuterol. [Updated 2020 Aug 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK482272/