Posted by Ueli (195.162.173.229) on March 17, 2001 at 10:07:50:
In Reply to: Good warning that we should not play posted by Bennie Sue on March 17, 2001 at 08:15:54:
There are different kinds of sustained-release/extended-release/controlled-onset medications.
Some pills are specially coated (or in a special capsule) to pass the acid environment of the stomach undamaged and release their contents in the intestines only. Obviously, such pills should be not split or otherwise damaged. The leaflet usually contains a warning about doing so.
For other pills the active ingredient is chemically altered or bound to a carrier substance, in such a way that it is absorbed slowly, over an extended time. There is no adverse effect in splitting such pills.
As to Verapamil SR, a quote from rxlist.com:
Sustained-Release/Extended-Release Tablets: The tablets are designed for sustained release of the drug in the gastrointestinal tract; sustained-release characteristics are not altered when the tablet is divided in half.
There is also a controlled-onset version of Verapamil: Verelan PM, to be take at bed time and starting its effect in the early morning. I would guess that this is not very suitable for clusterheads.
Finally, Dr. Goadsby mentioned somewhere, that the standard Verapamil is (for some unknown reason) more helpful for clusterheads than extended-release types.