When should we swap DMARDS?

I've been reminded this week that we often get this commonly performed swapping incorrect.

DMARDS are disease modifying antirheumatic drugs. We use these for a range of autoimmune diseases and we often have a recipe (sometimes evidence-based, sometimes not) helping dictate what we should use.

So when do we actually consider swapping to a different DMARD?

• When we need to find another medication that is more effective;
• When side effects have developed to the first medication we chose; 
• When it's the choice of the person taking it, for whatever reason;
• When there's a change in diagnosis;
• When pregnancy is being considered and we need to use DMARDs which are safe in this regard;
• When other medical conditions develop which make us reconsider the mix of medications being used.

Swapping is something we rheumatologists do commonly in an attempt to improve the situation. 

This week I've seen results where this improvement has not been achieved and the swap regretted.

Or at least, we chose the wrong DMARD to swap to. In one situation, the new drug caused more side effects and in another case, the new drug was even less effective resulting in more grief. 

It would be nice to have precision when we swap DMARDs.

Some way to measure something which will then inform the decision as to the new medication to use. 

For a better result, reasonably guaranteed. 

What's your experience of a DMARD swap?