From: dyer@spdcc.com (Steve Dyer)
Subject: Re: Dental work and epinephrine pellets?
Organization: S.P. Dyer Computer Consulting, Cambridge MA
Date: Mon, 14 Dec 1992 19:28:48 GMT

In article <1992Dec14.131936.15297@sei.cmu.edu> bjz@sei.cmu.edu (Barbara Zayas) writes:
>My dentist used two epinephrine pellets inside of one of my
>molars today (as he was replacing a crown).
>When I questioned the cause of the jitters, I asked about
>them possibly having been caused by the pellets.  The
>dentist's assistant said that the jumpiness would not have
>been caused by the pellets since they had (at that time) been
>removed an hour before (by my calculations, it was more like
>30 minutes...not 1 hour).  ...but I'm curious as to
>whether I just had a weird case of jitters or whether they
>might have been related to the pellets.
>
>I wondered if it would interfere with any medications that
>I'm taking (Ventolin and Intal)...they said not.  Maybe I was
>just extra antsy today...?

Nervousness and jumpiness is a common side (primary?) effect of
epinephrine; it is better known in casual speech as adrenaline, after
all.  I'd imagine it's used as a vasoconstrictor in dental surgery to
shrink capillaries temporarily to minimize local bleeding and to keep
the local anesthetic from diffusing away, though I am not particularly
familiar with with the use of these pellets in dentistry.

Now, while the vasoconstricting actions are due to epinephrine's
effect on alpha-adrenergic receptors, its stimulant effect on the
heart and its relaxant effect on smooth muscle (like the bronchioles)
are due to its actions on beta-adrenergic receptors.  That is, much
like Ventolin.  And, as you know, you can purchase epinephrine
aerosol inhalers over the counter for use in mild asthma as Primatene and
Bronkaid Mist.  A drug like Ventolin (albuterol, or salbutamol outside
the US) has little effect on alpha adrenergic receptors, and is said
to be selective for a subset of beta receptors, the beta-2 class, which
act on smooth muscle as opposed to the beta-1 receptors which are found
in the heart.  The hope is that this relative selectivity should minimize
the beta-2 adrenergic effects which are common with drugs like epinephrine
and isoproterenol.  Still, as you might be familiar already, nervousness
and tremor is not all that uncommon with a drug like Ventolin.

Epinephrine ordinarily has a rather short duration of action, as its
effects are terminated by reuptake into synaptic terminals and destroyed
by the enzymes COMT and MAO.  Albuterol is longer acting, because it
is not subject to this reuptake process, nor is it destroyed by COMT.
Still, it's not at all surprising to me that you might still be feeling
jumpy; you're already taking Ventolin, it's hard to predict a 1/2 life
for any individual for epinephrine, PLUS this sensation is somewhat
self-perpetuating.

It sounds to me like you had a simple case of excessive beta adrenergic
stimulation from being treated with the Ventolin and the epinephrine
pellets simultaneously.  Probably nothing to worry about, though you
might mention this to your dentist the next time, if there is a next time.
S/he might elect not to use the epinephrine pellets or perhaps, if your
asthma can handle it, delay your regular dose of Ventolin.  Of course,
I'm not recommending you do the latter--you yourself know what you can get
away with there.

-- 
Steve Dyer
dyer@ursa-major.spdcc.com aka {ima,harvard,rayssd,linus,m2c}!spdcc!dyer
Newsgroups: sci.med