A breath-enhanced nebulizer adapted for use in administering a nebulized pharmaceutical composition to a patient by inhalation wherein the patient is connected to a mechanical ventilator, comprising a. a housing with a generally vertical orientation with a breathing gas channel, wherein the breathing gas channel comprises an inlet in fluid communication with a mechanical ventilator and an outlet in fluid communication with a patient interface, and wherein breathing gases flow from the inlet to the outlet when the ventilator is in an inhalation phase of a breathing cycle, and wherein breathing gases from the ventilator are in fluid communication with inlet; b. wherein a nebulizer air flow at a nebulizer air jet creates a Venturi effect that draws a pharmaceutical composition solution from a reservoir through a liquid channel to a liquid orifice and wherein the pharmaceutical composition solution is directed towards the air jet such that the pharmaceutical composition solution is nebulized by contact with the air jet; c. wherein the breathing gas channel further comprises a Venturi section and wherein the nebulizer air jet and the liquid orifice are co-located in the Venturi section, and wherein the liquid orifice is in fluid communication via the liquid channel with the pharmaceutical composition solution in the reservoir; d. wherein the nebulized pharmaceutical composition is carried by the breathing gas flow to the patient interface, and wherein the breathing gas flow through the nebulizer is the exclusive source of breathing gases delivered to the patient; characterized in that, e. an internal body is nested in the housing, wherein the internal body defines the breathing gas channel, such that flow of breathing gases in channel travels downward and then after the gases pass through the Venturi section, the gases travel upward; f. wherein the breathing channel has a constriction in the gas channel, and wherein breathing gases flowing through the constriction in the gas channel during an inhalation enhances the Venturi effect to increase the rate of flow of pharmaceutical composition solution to the liquid orifice and concomitantly increase the rate of nebulization. a. a housing with a generally vertical orientation with a breathing gas channel, wherein the breathing gas channel comprises an inlet in fluid communication with a mechanical ventilator and an outlet in fluid communication with a patient interface, and wherein breathing gases flow from the inlet to the outlet when the ventilator is in an inhalation phase of a breathing cycle, and wherein breathing gases from the ventilator are in fluid communication with inlet; b. wherein a nebulizer air flow at a nebulizer air jet creates a Venturi effect that draws a pharmaceutical composition solution from a reservoir through a liquid channel to a liquid orifice and wherein the pharmaceutical composition solution is directed towards the air jet such that the pharmaceutical composition solution is nebulized by contact with the air jet; c. wherein the breathing gas channel further comprises a Venturi section and wherein the nebulizer air jet and the liquid orifice are co-located in the Venturi section, and wherein the liquid orifice is in fluid communication via the liquid channel with the pharmaceutical composition solution in the reservoir; d. wherein the nebulized pharmaceutical composition is carried by the breathing gas flow to the patient interface, and wherein the breathing gas flow through the nebulizer is the exclusive source of breathing gases delivered to the patient; characterized in that, e. an internal body is nested in the housing, wherein the internal body defines the breathing gas channel, such that flow of breathing gases in channel travels downward and then after the gases pass through the Venturi section, the gases travel upward; f. wherein the breathing channel has a constriction in the gas channel, and wherein breathing gases flowing through the constriction in the gas channel during an inhalation enhances the Venturi effect to increase the rate of flow of pharmaceutical composition solution to the liquid orifice and concomitantly increase the rate of nebulization.