Slow Release Meds, what does that mean?

[Jerry_NJ]

I have taken several medications over the years that have various claims that is supposed to mean, I believe, that the medication will be effective over an extended period of time, up to 24 hours.

I am taking Metoprolol with an "ER" designation, which I think means Extended Release,
I have taken Toprol and Rythmol with a "SR" designation, slow release

Any comment on my understanding/belief?

I also wonder if the term "release" is a misnomer.  That is, do the pills dissolve slowly (I doubt it) or does the designation refer to the metabolism processes of the body, i.e., the body takes a longer period of time to rid itself of the medication.  The latter being the case I must also assume that there is some medication present at the 24 hour point, but a good bit less than what is there shortly after ingestion of the medication.  This, it seem to me, would mean the metabolism of units-per-unit-time is proportional to the dose level, otherwise it would seem that the body could accumulate the small "carry-over" amounts each day until what.... could be bad news.

On the other hand, if the pill simply dissolves slowly one could think the metabolism process simply takes the medication out as it is slowly absorbed.

[Jerry_NJ]

Thanks

[ireneo]

I googled slow release medications and here's an excerpt from today's New York Times article:

In 1987, Mr. Lowey patented a 24-hour tablet based on a composition that attaches to the gastrointestinal wall until it becomes fully absorbed in the bloodstream. The attachment, he explained, prevented the body from eliminating the tablet, which typically takes less than 12 hours.

At About.com is an article about "extended release medications" which in part says:

Definition: Extended-release medications have special coatings or ingredients that control how fast the drug is released from the pill into your body. This may allow you to take certain medications only once or twice a day, instead of more often. Some extended-release medications have the letters "XL" or "LA" or "XR" in their name.

They both sound very similar to me. You can google the "slow release medications" if you want to see the full article. There are plenty of others as well. Hope this much helped a little.