What is a ceiling effect?

Let me answer your question a little more clearly. =]

The "ceiling effect" is when the highest level of that specific medication has been reached. At this point, the full effectiveness of the medication would be achieved and taking more would be pointless.

A lot of times pharmaceutical labs create ceiling effects to avoid from children accidentally ingesting a toxic dose of that medication. It also protects other internal organs from sustaining injury do to an overdose of anti-inflammatory medication.

its when the medication reaches it top effectiveness then levels off and stays at that level while its working. then when you take next dose it stays at top rate of dispersement.