ask your pharmacist

How do I know if my asthma inhaler still has medicine in it?

An old stand-by is the "water" test. Just put the inhaler in a sink or bowl full of water. If it floats, it's empty; if it sinks, it's full. But the test isn't always precise. And worse, water can get inside the inhaler. So it's better to rely on a more scientific method, such as an "inhaler chart" that you mark with each use.

Start with the total number of puffs in the inhaler and subtract your puffs each day. Many inhalers come with a log for this purpose. If you use an inhaler regularly, say four times daily, you can mark your calendar for the day the inhaler will be close to empty. Don't forget to reorder before you run out completely.

To help you remember when your medication is getting low some inhalers, such as the Serevent Diskus and Pulmicort Turbuhaler, now come with counters. Also available: a new reusable device called The Doser that attaches to any inhaler and tracks the number of puffs remaining.

Sources:
Handbook of Nonprescription Drugs. American Pharmaceutical Association, 1996.
Institute for Safe Medical Practices Medication Safety Alert, Asthma Inhalers, 1999.
The Doser product information. MEDITRACK Products, 2007.

This answer prepared 9/15/2000.
This information updated 1/2/2007.