MAPS: Drug potency (was: Flatliners and Media Hysteria)

["Nicholas V. Cozzi, Ph.D." <nvcozzi@xxxxxxxxxxxxxxxx>]

At 01:58 AM 1/5/99 -0600, you wrote:

>The way the word 'potency' is used in reference to drugs causes much
>confusion.  What does it really mean for one drug to be more 'potent' than
>another?

Actually, potency is well-defined.  Typically, one compares the EC50
(effective concentration for 50% effect) among different drugs.  For
example, a drug that produces 50% of the maximal contraction of a muscle at
100 nanomolar concentration is 1000X more potent than a drug which produces
50% of the maximal contraction at 100 micromolar concentration.

>A strictly technical definition would be that it requires less mass of the
>drug to achieve a similar level of effect.

Umm. . .not less *mass*, but fewer molecules.

>By this definition LSD is
>1000-2000 times more potent than DXM, as many would equate 250 microgram
>dose of LSD (~1 hit) to 250-500 milligrams of DXM.  However, it's complete
>nicompoopery to argue that an average acid trip is 1000 times as intense as
>an average DXM trip.

Exactly.  To get *the same intensity*, one requires 1000X *less* LSD.


Nicholas V. Cozzi, Ph.D.
Department of Pharmacology
East Carolina University School of Medicine
Greenville, NC  27858

------------------
MAPS-Forum@xxxxxxxx, a member service of the Multidisciplinary Association
for Psychedelic Studies (to become a member, see www.maps.org/memsub.html).
To [un]subscribe, email the message text,
[un]subscribe maps-forum youraddress to majordomo@xxxxxxxx