Theory 04/Thresholds & Tipping/Antibiotic combinations
Synergy Tips at a Ratio
The claim
Combination synergy appears only within a range of dose ratios, so the same pair of drugs can be synergistic, additive or antagonistic depending on proportion.
01Mechanism
Each drug acts on a different node; the interaction is a product of fractional effects, which peaks at a particular ratio rather than at maximum dose of either.
02Prediction
Synergy should peak at an intermediate ratio.
03Refutation
Synergy depending on dose magnitude rather than ratio would remove the optimum.