Vide Alternam Partem.

Before I begin I have one more personal note, yesterday while at work I overhead one of the nursing staff talking about using an oral dose of Vancomycin. If any of you have been following my earlier posts I spoke about how oral doses of Vancomycin are used only to treat GI issues. Come to find out that this patient was at high risk for an overgrowth of bacteria known as C dificile and the Vanco was being used to pre-treat the issue. But, thanks to my research and blog I knew the context and the generally prescribed way in which Vanco is used. Go me.

The last time I 'blogged' I spoke about a drug being used called Racemic-Epi. That is going to be the subject of today's DotW feature.

Ok, first off I need to define a bunch of terms. I am currently enrolled in an Organic Chemistry course, and I am really enjoying it. The terms that I am going to use are from Organic Chemistry, as Epi or Epinephrine is an organic molecule.

Epinephrine looks like this:
It is more commonly known as Adrenaline. It is commonly known as Epinephrine because it is produced by the adrenal glands which are above - epi - the kidneys and in Greek nephro means kidney. So, epinephrine means above the kidney.

Technically speaking, epinephrine is a sympathomimetic catecholamine. It causes quickening of the heart beat, strengthens the force of the heart's contraction, opens up the airways (bronchioles) in the lungs and has numerous other effects. The secretion of epinephrine by the adrenal is part of the fight-or-flight reaction. Adrenaline is a synonym of epinephrine and is the official name in the British Pharmacopoeia.
(http://www.medterms.com/script/main/art.asp?articlekey=3286)

We now have a basic understanding of Epinephrine, or, Adrenaline.
So, what makes it so special if it is called racemic?

We have to do a few definitions before we can define it completely. A racemic mixture is a 50/50 mixture of what are known as R and S enantiomers. An enantiomer is a mirror image of a molecule; when you have enantiomers they can not be placed directly on top of each other. To understand enantiomers think about your right and left hands. They look like mirror image of each other, but they can't be placed directly on top of each other with out rearranging things.
To say that an enantiomer is R or S means that it has bonds around a carbon that rotate in either a clockwise - R - direction or counter-clockwise - S - direction.
In other words, a racemic mixture is a mixture that has carbons with bonds that are counted in a clockwise direction and bonds that are counted in a counter-clockwise direction.
This is important because the way in which bonding occurs on a carbon atom can really affect the way in which the molecule is able to act.

Racemic-epinephrine is commonly used in an aerosol form to treat airway problems. There is, however no standard for treating a respiratory ailment with racemic-epi.
Several studies¹ have shown that nebulized racemic epinephrine, which stimulates both α-adrenergic and β-adrenergic receptors, is as effective or superior to albuterol in relieving airway obstruction in patients with viral bronchiolitis. Some studies²³ have shown no significant difference in the effectiveness of nebulized therapy with epinephrine and albuterol in a hospital setting. But short-term benefits in respiratory rate, oxygen saturation, and clinical score have been observed with the use of epinephrine. A single outpatient, placebo-controlled trial⁴ noted a statistically insignificant but potentially clinically meaningful 12% decrease in the hospitalization rate in the epinephrine group. One study⁵ in an ED showed that patients treated with epinephrine were discharged significantly earlier than patients who had been treated with albuterol.
(http://www.chestjournal.org/content/129/4/1114.2.full)

It is significant to note that it is commonly not the practice for medicinal chemists to use a racemic mixture of any drug. The idea is to isolate either the R or the S enantiomer and study those effects individually before you throw them together. Putting R and S together without a solid knowledge of what each will do is kind of like a box of chocolates. You don't know what you are going to get.
In this case, however, it seems that the benefits are high and the general outcomes positive.
I will continue to explain more stuff about organic chemistry as I myself learn more.