Willow - Geez, I'm really sorry I missed that; I seem to be getting worse than better. Since the other pharmacist quit (thank the gods) I only have a relief pharmacist to fill in for me, and when he's needed somewhere else I get little notice that I have to work. I work approx. 80 km from home and have to stay overnight between shifts. I have been working four to six 12 h shifts a week for the past little while and do forget where I was answering when I left. I use to have the internet at work (and will again), but the last pharmacist broke it while I was away in Oct. and I still haven't got it back, so I have no way of getting to this site.

Anyway, Lexapro™ (escitalopram) which is the S-isomer of citalopram. Celexa™ (citalopram) is a mixture of the R- and S-isomers. Isomers refer to the "handedness" of a molecule. All of the atoms of citalopram occur are exactly the same in both isomers, but their three-dimensional orientation in space is different. The R- and S-isomers are three-dimensional mirror images of each other, sort of like right and left hands. The R- and S- designations refer to the way that each isomer bends polarized light. The R-isomer bends the light to the right, and the S-isomer bends the light to the left (the "S" designation stands for "sinister", a holdover from the days when left-handed people were thought to be more likely to be evil - I can't remember the exact reason for this). Another way of classifying the these <A target="_blank" HREF=http://www.wordreference.com/english/definition.asp?en=racemic>"racemic"</A> mixtures is by using "levo-" (ie. l-isomer, which bends polarized light to the left - is the same as the S- designation) and dextro- (ie. d-isomer, which is the same as R-). I guess someone thought that chemistry wasn't confusing enough.

Most molecules of drugs are a mixture of both R- and S-isomers and in many cases the isomers are equally active (ie. bind to the appropriate receptor with equal <A target="_blank" HREF=http://www.wordreference.com/english/definition.asp?en=affinity>"affinity"</A> (definition 6a), but there are notable exceptions. For example, amphetamine (ADDeral™) is a racemic mixture, but dextroamphetamine (Dexedrine™) is much more pharmacologically active than levoamphetamine, thus a lower dose of the dextro-isomer can be used.

As for citalopram, the S-isomer (or "escitalopram") is more pharmacologically active than the racemic Celexa. In reality, I do not consider the difference between Celexa and Lexapro to be clinically significant. The patent protection for citalopram is to run out soon, so the company that makes it separated the 2 isomers and began marketing the S-isomer as a new drug, with all new patent protection. Man, I really hate marketing.

So, to answer your question, I have to make a guess as to what is going on when taking Lexapro with wine. I find that all SSRIs potentiate the effects of alcohol, thus it takes less alcohol to get to the "feel good" stage.

Ordinarily this can be a good thing (if you are drinking at home - or other safe environment - and not being preyed upon by meat-market vultures), but a problem arises after 3 to 5 alcoholic drinks. Ethanol inhibits a hormone called ADH (antidiuretic hormone) which helps the body reabsorb water from the kidneys back into the body during the process of concentrating urine. Enough ethanol (3 to 5 ounces of ethanol in most people) causes the body to lose more water than it should, and results in having to pee every 15 minutes, and significantly contributes to hangovers.

The dilute urine that is peed off can also may a quicker than normal excretion of Lexapro (ie. shortening the elimination half-life of the drug). Alternatively, the dehydration due to ADH inhibition can increase the concentration of Lexapro in the body, thus increasing the incidence of side effects from the drug. If you compare the body to a glass of water, dehydration leads to less water in the glass. So if one takes the same dose of a drug when when dehydrated as when not the concentration of that drug in the body essentially increases, which may lead to an increase in the drug's effects (and side effects). In a worst case scenario a drug can reach toxic levels via this mechanism.

Whether there is an increase or decrease in the concentration of a drug due to the inhibition of ADH (ie. dehydration) is dependent on a number of individual factors. The main factors being: the water v. fat solubility of the drug; the relative amount of an individual's body fat; the amount of ethanol consumed; the individual's natural levels of ADH; and the sensitivity of an individual's ADH concentations to the effects of alcohol. Drugs that are more water soluble are more readily peed off. Lexapro is relatively more fat soluble (which is one of the reasons the drug only needs to be taken in once daily doses).

So, determining how much alcohol is needed to change Lexapro's concentration (increase or decrease) in a particular individual's body is not easy to estimate. This and the increase in the depressant effects of alcohol is probably why your doc is p.o'd at you over the wine consumption.

The muscle knotting may be due to many factors. You may need a slightly higher dose of Lexapro to compensate for an artificial increase in concentration from the wine; or you may need a slightly lower dose of Lexapro, as muscle pain and cramping can be seen when doses are too high; or the depressant/anxiolytic effects of the wine is loosening you up (ie. the wine is acting as an anti-anxiety agent, similar to a benzodiazepine).

The above are only guesses, and I have no idea which one(s) is/are causing your muscle knotting and pain. Sorry that I can't be more specific, but all of the above effects can be occurring at the same time, to some degree.

Again, I am sorry for the delay in answering (if the above is indeed a correct answer in your case) - Cam

To fully understand a concept is to be unable to convey it's intricacies verbally; only when one can sense it emotionally, does one understand.