3 Comments

1. Troy  •  May 9, 2009 @6:06 pm
   

   It is chemically related but isn’t classed as a TCA because it isn’t an antidepressant. It is classed as a muscle relaxant.
   .
   Edit:
   Actually that research says the same thing I did. it was synthesized to be a TCA but didn’t work, but did work as a muscle relaxant. This happens pretty frequently. Viagra was designed for blood pressure, but didn’t work that well, but the old guys in the trials suddenly didn’t have erectile dysfunction.

   It is not used as an anxiolytic. The comparisons to benzos were in regard to muscle spasms. Also, wikipedia is open to editing from anyone, so take anything on there with a grain of salt.

2. Scott  •  May 12, 2009 @6:19 am
   

   Hey. I can see why your confused about its structure/activity relationship.

   I generally take the Merck Index as the bible on therapeutic uses, and its classified there as muscle relaxant and not as a thymoleptic (anti-depressant.)

   It does look like a thymoleptic… it has an annealation angle different from that of neuroleptic tricyclics, it lacks an electron-withdrawing substituent, and so on.

   But it also looks similar to some cholinergic antagonists! I’m talking about drugs like pirenzepine and AF-DX 116. The amine on cyclobenzaprine mimics the choline end of acetylcholine, the major neurotransmitter involved in muscle signaling. The bulky tricyclic end of the compound simply “gets stuck” in the cholinergic receptor, preventing acetylcholine from interacting with the receptor. If acetylcholine can’t interact, then the receptor doesn’t send a signal for muscle contraction, and the muscle relaxes.

   In other words, cyclobenzaprine acts like really fat dude who’s blocking the door to your room. When he’s in the way, you can’t get in to do what you need to do.

   Some tricyclics tend to have the problem of blocking cholinergic receptors, producing symptoms like dry mouth. The degree to which they do this differs from drug to drug, as well as the type of cholinergic receptor that they affect. Some tricyclics can even agonize these receptors, producing symptoms like drooling and salivation. There are other associated symptoms in addition to these when it comes to enhancing or diminishing the effect of acetylcholine.

   Sometimes it’s not possible to predict the activity of a molecule from its structure. Even though cyclobenzaprine has all of the pharmacaphore of a tricyclic antidepressant, it doesn’t principally act this way.

   I hope this answers your question. If you have any other questions on this, feel free to email me.

3. mdGreg C  •  May 12, 2009 @2:11 pm
   

   Neat Stuff, Scott.

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