Citalopram and Escitalopram

[kenko]

Got some questions regarding this 2 antidepressants.

I understand they are different drugs but quiet alike. I noticed that Citalopram half-life is around 35 hours and Escitalapram is 25-32 hours. Please correctme if I am wrong.

Is there any other difference?

Thanks
kenko

[Nik]

In practice (and in theory) there is very little difference between the two. According to a recent meta-analysis from The Lancet in 2009, escitalopram was ranked as having one of the highest efficacies as an anti-depressant, although I can't see why citalopram should be considered as less effective. Both are generally well tolerated and are weak inhibitors of CYP2D6.

[kenko]

Thanks NiK for your qucik response.
So theretically if you would swap escitalopram for citalopran it would not make any difference.is that right?

and also what would happen if some who is prescribed citalopran would take a dose of escitalopram by mistake?

thanks
kenko

[minisini]

Well they are enantiomers no? I one escitalopram is an isolated enantiomer of citalopram? I citalopram contains escitalopram and another enantiomer. Usually in these cases one of the enantiomers is the active form and the other is blamed for all of the side effects of the medicine. Therefore, to remove the unwanted enantiomer means more active ingredient and less side effects.

[johnep]

Nah, just a means of extending patent life, similar was Clarityn and Neo-Clarityn.
johnep

[hibernia]

Nah, just a means of extending patent life, similar was Clarityn and Neo-Clarityn.
johnep

I agree with you. Other example was the introduction of Nexium just as Losec got to the end of its patent life.
Hopefully pharmacists won't believe all the guff they read in drug company glossy brochures. Doctors may fall for that sort of scientific sounding babble but the reason we learned pharmaceutical chemistry was so that we would understand these things.
Most of the supposed 'benefits' of the new form come from using a higher equivalent dose. 10mg of escitalopram is equivalent to 20mg of citalopram so if you give 20mg of escitalopram you get a greater response, just as you would if you doubled the citalopram. Don't see any clinical significance in the slight difference in half-life, both are given once daily.

[Nik]

I too would have to agree with hibernia and john re reason for escitalopram. The theory behind the use of escitalopram (perhaps from pharma) is that the R enantiomer of citalopram binds to the serotonin reuptake transporter but doesn't inhibit it, ie it interferes with the pharmacology of the pure s enantiomer. Also, having the pure s enantiomer supposedly removes the mild antihistamine effects of citalopram (well whatever weak antihistamine effects it has anyway). Whilst all this may be true in the pharmacology labs, its difficult to extrapolate that to a significant clinical effect. NICE recommends the use of generic SSRI's first line anyway.

[kenko]

So then, if in the event of a drug error where escitalopran was given instead of citalopram as a one off, then no problems or side effects would occure. hence there would not be the need to give citalopran as escitalopran has already the active ingridient? am i understanding this right? thanks

[johnep]

The problem would be that you have lost money owing to the cost difference. Nature generally tends to be left handed. When racemic mixtures are given then dosage usually twice that of the laevo form.
johnep

[kenko]

sorry, did not get that 1. xD
cud u please simplify it.

kenko