Self-puncturing liquid drug cartridges and an associated inhaler are used to deliver one more separate doses of an aerosolized liquid drug. A cartridge includes a needle assembly coupled to a drug container. The needle assembly includes a hollow needle and is reconfigurable from a first configuration to a second configuration upon insertion of the cartridge into the inhaler. In the first configuration, the hollow needle does not extend into the container. In the second configuration, the hollow needle extends into the container. The inhaler includes an aerosol generator that includes a vibratable membrane that aerosolizes liquid drug ejected from the cartridge for inhalation by a patient.