Inhalation devices with a reduced risk of blockage

An aerosol inhalation device, comprising:

• a mouthpiece;
• a canister of pressurized hygroscopic medicament, said canister having an end fitted with a dispensing metering valve feeding said medicament to said mouthpiece, said metering valve having a valve stem provided with an inlet port;
• said valve stem being movable between an inoperative position in which the inlet port is located outside the metering valve and an operative state in which the inlet port is located within the metering valve;
• and
• a cap of elastomeric material fitted over the end of the canister provided with the valve, said cap being provided with a frusto-conical central portion through which the valve stem passes and protrudes, such that in the inoperative position of the valve stem, the cap shields the inlet port from a user's breath and upon movement between the inoperative and operative positions the cap brushes the surface of the valve stem.