Cost-minimization is a tool used in pharmacoeconomics to compare the cost per course of treatment when alternative therapies have demonstrably equivalent clinical effectiveness.
[1] Therapeutic equivalence (including adverse reactions, complications and duration of therapy) must be referenced by the author conducting the study and should have been done prior to the cost-minimization work.
Since equal efficacy and equal tolerability is already demonstrated, there is no requirement to find a common efficacy denominator as would be the case when conducting a cost-effectiveness study.
If efficacy and tolerability is demonstrated, however, then a simple comparison of "cost/course of treatment" can suffice for the purpose of comparing two or more therapeutically equivalent treatment alternatives.
When conducting a cost-minimization study, the author needs to measure all costs (resource expenditures) inherent to the delivery of the therapeutic intervention and that are relevant to the pharmacoeconomic perspective.