If you have asthma, do you ever use a "rescue" inhaler to stop an attack? Or maybe you use it before exercising to prevent problems? If so, here's a quick refresher to make sure you're on top of your game.

Most rescue inhalers that contain albuterol are now labeled HFA. They use a propellant that doesn't harm the earth's atmosphere.

The first time you use your HFA inhaler, prime it to make sure it releases the right dose. Aim the spray away from your face and pump four times.

Also do this when your inhaler hasn't been used in a while.

You can expect a softer spray and a different taste with an HFA inhaler as compared to the older type.

You may not feel like you're getting as much medicine from this one as with previous inhalers, but it does in fact deliver the same dose, so don't take more than your doctor has prescribed.

So, how do you keep track of just how much medicine is left? Most don't have a visible counter, so it's a good idea to write down how many doses you've used. And be sure to include those first 4 sprays.

You'll want to refill your prescription well before the canister is empty. Because when you need it, you need it--and you won't have time to run to the drug store to get it refilled.

Rescue inhalers can be key to managing asthma but don't overdo it. If you're using them more than two or three times a week for a reason other than exercise, it may mean your asthma is out of control and it's time to see your doctor.