Huong N. answered • 07/07/20

Pharmacist, PharmD, MTM

Different NSAID's exhibit different degrees of selectivity for COX-1 and COX-2 enzymes, which is a major factor in defining the side effect profile. For example, aspirin and naproxen have greater COX-1 selectivity while meloxicam and diclofenac have greater COX-2 selectivity. Celecoxib is considered a COX-2 inhibitor because of its very high selectivity for the enzyme.

I'm not sure what you mean by collecting in compartments. If you are referring to a drug's volume of distribution, then you can tell if a drug has low or high volume of distribution by looking at the numbers. A hydrophilic drug has a low volume of distribution, closer to 1 L/kg so it tends to stay in plasma. Lipophilic drugs have higher volumes of distribution, which means it tends to enter extravascular compartments. Each NSAID will have a different volume of distribution. For example, diclofenac has a lower V_{d }so it tends to stay in plasma vs. meloxicam which has a much higher V_{d}.

And yes, of course there are mutations of COX-1 and COX-2 but I am not aware of any literature on its pharmacodynamic interactions with NSAIDs