Is it OK to use "Group A, B, C ..." in a manuscript?, I am currently preparing a manuscript which lies in the biomedical field.

My study has five groups, and their identification is a bit tedious to describe in a full term (something like "'abcd' medicine + 10mg of 'efgh' medicine group").

Therefore, In the results section, I want to maximize word economy by not directly lettering out the specifics of the group, but just referring it to Group, such as A, B, C, D, and E. I am planning to propose a table that clearly explains the initial letters (A, B, C, D, E) of the group and its specific descriptions in the materials and methods section.

However, upon my research, many articles just endured the inefficiency of fully describing the group whenever it has to be mentioned. Is this some kind of a rule that has to be kept when writing a manuscript?
In general, on the biomedical field Latin letters (A/B/C or a/b/c) are reserved for the figure panels (e.g. "Figure 1 A and B clearly show..."). Typically, biomed articles tend to have a lot of panels per figure, so it is suboptimal to use these letters for anything else. It is much more handy for the reader, if experimental groups have human-readable names that are clearly defined in the method section. A little fantasy may be helpful. For example,


Group 1 - placebo control - "Placebo" 
Group 2 - 10 mg Blabla drug - "B10"
Group 3 - 25 mg Lalala drug - "L25"
Group 4 - Blabla drug + Lalala drug, once per day - "BLI"
Group 5 - 20 mg Blabla + 30 mg Lalala - "B20L30 and etc.