It is usually given by the inhaled route for direct effect on bronchial smooth muscle. This is usually achieved through a metered dose inhaler (MDI), nebulizer or other proprietary delivery devices (e.g. Rotahaler or Autohaler). In these forms of delivery, the maximal effect of salbutamol can take place within five to 20 minutes of dosing, though some relief is immediately seen. It can also be given intravenously.