Activent Mechanism of Action

Pharmacology: Pharmacodynamics and Pharmacokinetics: Salbutamol is used as bronchodilator in the management of reversible airway obstruction, as in asthma and in various forms of chronic obstructive pulmonary diseases.
Salbutamol is a direct-acting sympathomimetic amine with mainly beta-adrenergic activity. It acts selectively on beta-2 adrenergic receptors in the lungs to relax bronchial smooth muscle, thereby relieving bronchospasm and reducing airway resistance. It also relaxes the smooth muscle of the uterus and enhances vascular supply to the skeletal muscle. These are said to result from increased production of cyclic adenosine 3',5' - monophosphate (cyclic 3',5' - AMP) caused by activation of the enzyme adenyl cyclase.
Following oral administration, salbutamol is well absorbed from the gastrointestinal tract. It is metabolized in the liver and possibly in the gut wall. Estimated plasma half-life of salbutamol ranges from 4 to 6 hours.
Salbutamol is rapidly excreted mainly in the urine within 48-72 hours after oral administration, little portion is excreted via the feces.