Cat coughs after drinking water

My 18 year old occasionally has a coughing fit after drinking water. It doesn't happen every time but it happens enough for me to get on here and ask you guys about it. It sounds like the cough he did before we started giving him inhalers for his asthma. Any idea what this could be? I thought it happened when he had really cold water, but he had lukewarm water earlier today and did it. He never coughs anything up.

I used to work at a nursing home for two years. Some of the residents were not allowed to drink water because they could choke on it. They got honey in their coffee. I don't know what causes this, but if old people can choke on water, I guess cats can too.

So, he has already been diagnosed with Asthma?  Naturally, my first thought was asthma, but if he's already on an inhaler, then you already know about that.  It could just be, like us humans, that he gets some water down the wrong pipe.  One of my cats does that when he drinks from the fountain, and only then.  But it scared me so much, because he consistently does it, that I had him checked out for heart disease, since coughing is a symptom of heart disease as well.  If it's only when he drinks, it's probably just the wrong pipe thing, but it's definitely worth a call the the Vet, just to ask about it, for peace of mind, IMHO.