Antidepressant pharmacology columns published by Dr. Preskorn
Published in Journal
of Psychiatric Practice
(formerly the Journal of Practical Psychiatry and Behavioral
Understanding the basics of antidepressant pharmacology
The columns in this section discuss basic pharmacologic principles
relevant to understanding the mechanistically defined classes
of antidepressants. It reviews: (a) the history of antidepressant
pharmacology from a developmental perspective eight classes,
(b) the meaning of selectivity and specificity, (c) the extrapolation
from in vitro binding affinity to different targets to clinical
action, and (d) summarizes the clinical pharmacology of antidepressants
as determined by formal clinical trials.
- Jul. 2000 -- The Relative
Adverse Effect Profile of Non SSRI Antidepressants: Relationship
to In Vitro Pharmacology -- This article continues
the discussion of the relationship between the in vitro
binding affinity and the clinical pharmacology of the various
classes of antidepressants. This article reviews the adverse
effect profiles of non SSRI antidepressants: bupropion,
imipramine, mirtazapine, nefazodone, and venlafaxine.
- May. 2000 -- The
Adverse Effect Profiles of the Selective Serotonin Reuptake
Inhibitors: Relationship to In Vitro Pharmacology
- This column reviews the relationship between the in vitro
binding affinity and the clinical pharmacology of the various
classes of antidepressants. In addition, the column will
address how it relates to the adverse effect
profiles of the five marketed selective serotonin reuptake
- Mar. 2000 -- Imipramine,
Mirtazapine and Nefazodone: Multiple Targets - General
Bucky Turgeson in the Stanley Kubrick movie, Dr. Strangelove,
was mighty proud of his aerial warriors and their B?52s.
This series of planes, first rolled out in the 1950s, are
still being used. The longevity and value of these planes
are the result of their ability to deliver so many different
types of payloads to their targets.
For similar reasons, I suspect Bucky would have loved
imipramine, mirtazapine, and nefazodone. These drugs are
multiple action antidepressants that are capable of affecting
multiple targets at the concentrations achieved over their
clinically relevant dosing range. That fact distinguishes
them from the norepinephrine selective reuptake inhibitors
(NSRIs) (e.g., desipramine) and from the selective serotonin
reuptake inhibitors (SSRIs) (e.g., sertraline). NSRIs
and SSRIs have a binding affinity for the site believed
to mediate their antidepressant efficacy that is at least
an order of magnitude greater than their binding affinity
for other neural mechanisms of action
This column examines the differences between the in vitro
pharmacology of the multiple mechanism of action antidepressants
(e.g., imipramine, mirtazapine, nefazodone) and that of
the single mechanism of action antidepressants (i.e.,
SSRIs and NSRIs) account for the differences in their
- Jan. 2000 -- Bupropion:
What Mechanism of Action? - This column discusses
how to assess the potential relevance of in vitro binding
studies to the clinical use of a drug. The series has used
the various classes of antidepressants as examples to illustrate
basic pharmacologic principles. In the previous columns,
I have focused on antidepressants that are serotonin uptake
pump inhibitors (SRIs), the selective serotonin reuptake
inhibitors (SSRIs), and venlafaxine. In this column, I will
discuss bupropion, which has an in vitro and clinical pharmacology
substantially different from that of a serotonin uptake
- Nov. 1999 -- Two
in One: The Venlafaxine Story - This column, examines
the antidepressant medication, venlafaxine, to illustrate
a drug with a binding affinity that sequentially affects
two different neural sites of action over its clinically
relevant dosing range. Specifically this column addresses
the following questions:
- Why does the adverse effect profile of venlafaxine
qualitatively change as its dose is increased, in contrast
to the adverse effect profile of an SSRI?
- Why does venlafaxine have an ascending dose?antidepressant
response curve in contrast to the flat dose response
curve seen with SSRIs?
- Why are higher concentrations of venlafaxine needed
to achieve antidepressant efficacy in comparison to
several of the SSRIs?.
- Sep. 1999 -- De-Spinning
In Vitro Data - "Spin" refers to
framing events in a way that is favorable to the person
doing the "spinning." It is a term that becomes
commonplace during political campaigns. Candidates running
for major office have one or more "spin doctors"
who specialize in putting a "positive spin" on
events affecting their candidate and a "negative spin"
on events affecting their opponents. While generally not
a lie, "spin" may nevertheless mislead the listener.
So what does "spin" have to do with in vitro
Companies naturally endeavor to portray their products
in the most favorable light possible. Sometimes, they
can do this using compelling, straightforward data. At
other times, however, they have to rely on "spin."
For that reason, clinicians need to be able to critically
examine the basis for promotional claims. The goal of
this column and the others in this series is to present
a way of critically thinking about the potential relevance
of in vitro data to actual clinical use of a drug.
- Jul. 1999 -- Defining
"Is" - The inspirations for this column often come
from questions posed by colleagues around the country. One
frequently asked question is whether differences in the
in vitro potency of medications have any physiological/clinical
This column begins to look at the answers to questions
· What is the relationship
between in vitro potency and in vivo effects?
· What does "selectivity"
· How does "selectivity"
relate to modern psychiatric drug development?
· What are the implications
of such development for our understanding
of psychiatric illnesses
and their treatment?
This column is based in part on material contained in
two of my recent books and briefly reviews in vitro binding
affinity and the concept of pharmacological selectivity.
- Mar. 1999 -- Finding the
Signal through the Noise: The Use of Surrogate Markers
-- Surrogate markers have been used successfully in
clinical trials in a number of therapeutic areas such as
lipid reduction with statin drugs. This article discusses
how surrogate markers might be used in psychiatric clinical
trials to enhance the power and efficacy of studies by increasing
the signal:noise ratio. The goals are to:
- Better define the optimal dose (i.e., concentration)
of psychiatric medications, and
- Elucidate clinically important biological variance
in the site of action of a drug.
- Mar. 1998 -- Marooned:
Only one choice - This column presents a way of
organizing available antidepressants into eight classes
based on their mechanisms of action and
illustrates how this classificatory system can help the
Anticipate what effects these medications will produce
in a patient when
used alone or in combination with other medications.
Rationally move from one class of antidepressant to another
in the event
that the first one selected either did not produce an
adequate response or
aused treatment-limiting adverse effects.