An apparatus to administer drugs to mechanically ventilated patients includes a mechanical ventilator, an artificial airway to be associated to a patient and a ventilation circuit connecting the mechanical ventilator to the artificial airway. The ventilation circuit includes: an inspiratory line, a dry powder inhaler disposed in line on the inspiratory line and a connector operatively connected to the dry powder inhaler and to the inspiratory line. The connector includes: a first duct facing an outlet port of the dry powder inhaler and connected or configured to be connected to a tube section of the inspiratory line placed downstream the dry powder inhaler; a second duct facing an air inlet port of the dry powder inhaler and connected or configured to be connected to a tube section of the inspiratory line placed upstream the dry powder inhaler.