Multiple Comparisons in repeated measures of unequal sample size and unequal repetitions.

[Sujithpeta]

Hey, 

I have a data set with cancer patients who are tracked longitudinally for cancer drug use and their respective outcome while they are in the drug period. A patient could change from Drug A to Drug B during the longitudinal tracking and outcomes (Cost, no. of ER, Inpatient admissions, etc.) are only assigned respective to the drug the patient is on. 

Now, I want to test for statistical significance with multiple comparisons across the group for each outcome. Note: Groups have unequal sample size and unequal repetitions (i.e. a patient can just be on drug A and other patients can be on Drug B and Drug C for time we tracked). 

Appreciate if I can instructions on steps to follow and which proc procedures to use with some code example would be great.

Thanks