Suggestion:

You can achieve an isobologramme

on a graph, in X: the effect of substance A only (0% to 100% effect)

in Y : same with substance B

you connect by a straight line the two dots 100%

if your experimental point (A + B) is on this right you have an only additive effect

above : potentiation effect (underneath : antagonistic effect)

and the margin tells you in % the gain (or loss) from the additive effect

Best regards Philippe

Hi!

You can use also CDI (coefficient of drug interaction). It is calculated as follows:

CDI=AB/(A×B).

AB is the ratio of the 2-drug combination group to the control group and A or B is the ratio of the single drug group to the control group.

CDI

Please refer to the drug combination work of Ronald Tallarida, Temple University School of Medicine (isobolography and curvilinear isobolography should be helpful).  Try starting with J Clin Pharm Ther. 2013 Jun;38(3):190-5.

You could try and use Excess over Bliss. It's the NIH recommended way. I'll put up an attachment on how to calculate it asap

Where is Excess over Bliss compared to CalcuSyn?  There is no comparison in this paper:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4360667/

which introduces Excess over Bliss

I apologize for not uploading it earlier but here is the attachment. Hope it helps! I am not sure how it compares to the calculations employed by Calcusyn though.

UPDATE (Sept 30 2016)

THERE IS AN ERROR IN THIS SHEET! PLEASE USE THE NEXT ONE

Thanks.

I just noticed a calculation error in the sheet I uploaded.

Please see and use the following sheet.

My apologies

The COMBENEFIT software is very user-friendly. Try to use it.

http://www.cruk.cam.ac.uk/research-groups/jodrell-group/combenefit

Hello everyone,

I tested the single and combined effects of two drugs on the protein expression of a gene. I got a weird results if I used the above mentioned CDI methods. Any advice is greatly appreciated.

After normalising the protein expression levels using Western blot to the saline-paired control, i got the following relative averaged expression values:

Control: 1

Drug A: 1.3

Drug B (50 nM): 1.3

Drug B (100 nM): 1.3

Drugs A + B(50nM): 1.7

Drugs A +B (100nM): 4.0

CDI for Drugs A + B(50nM) = 1.7/(1.3x1.3)= 1.0

You can use CompuSyn it is free download

Hi everyone,

I use compusyn it's helpful and easy to use. Noted that i used the essential oils for treatments.

There is an other software synergyfinder you can use more than 2 drugs.

Find in attachment the paper that explan all details about synergyfinder

Good luck! 😊

If you were interested, also look at this link and the Compusyn software tutorial.

Book Tech Talks. Drug Combinations Synergism or Antagonism Compus...