To make sure that inhaled asthma medication reaches your airways — not just the back of your throat — your doctor may recommend attaching a spacer, a simple device that makes it easier to use a metered-dose inhaler.

Spacers work by discharging the medication into a holding chamber, where its particles are held in suspension for three to five seconds. During this time, you can more easily inhale the drug with one or more breaths. Large particles that cannot reach the lung fall out onto the walls of the spacer.

Proper spacer use can double the amount of medicine delivered to the lung and greatly reduce the deposition of medicine into the throat and upper airway.

The use of spacers also makes it possible to give inhaled medicines to children and patients with poor coordination. (Spacers with a valved septum help young children use metered-dose inhalers, and infants can use spacers with a mask instead of a mouthpiece.) Also, spacers reduce the local side effects (cough and oral candidiasis, or thrush) from inhaled steroids and allow administration of high doses of medication when needed.

To use a spacer:

• Remove the cap for the inhaler and shake the inhaler.
• Attach one end (usually labeled) of the spacer to the mouthpiece of the inhaler.
• Exhale slowly and steadily.
• Place your lips around the spacer mouthpiece, behind your front teeth.
• Start to inhale slowly and at the same time press the canister once to release a dose of the medicine. Continue to inhale very slowly and as deeply as possible. Some spacer devices will make a whistling sound if you are breathing in too fast.
• Hold your breath for about 10 seconds.
• Breathe out slowly and steadily.
• After using a corticosteroid inhaler, rinse your mouth with water and spit out to avoid thrush.
• Keep the cap on when the spacer is not in use and wash your inhaler in water and a mild detergent once a week.