Q. On the mitzvah of drinking on Purim does it have to be wine only? Can you drink some wine, like a cup and then other liquor?

A. Rashi (Megila 7b) explains that the drink is wine. Biur Halocho (695: 1) quoting Eliahu Rabba, mentions that the reason why we are required to drink on Purim is to commemorate the miracles that happened and those occurred at banquets where wine was imbibed. Meagley Tzedek (on Megila L. 32) avers that therefore wine only should be used, as this was the drink offered
Mata’amei Yakov (Likutim 340) compares this to Chanuka lights where olive oil is the preferred fuel, but other flammables are also acceptable. Rivavos Efraim (O.H. 8 p. 478) also seems to suggest that wine is to be used. There are also Cabalistic reasons in the ingesting of wine (Mishnas Yosef p.111, quoting the Arizal)
Others write that since the main purpose of this mitzvah is to reach the stage of “Ad Delo Yoda”, it does not matter what beverage one consumes (Inyono Shel Yom p.375, based on the Maharal.)
Orchos Rabenu (P. 78) mentions that the Steipler Gaon zt”l ruled that all liquors could be used, however, one should drink a bit of wine also. So too is the opinion of Horav Shlomo Miller Shlit”a, however he recommends to drink a revi’is.

Rabbi A. Bartfeld as advised by Horav Shlomo Miller Shlit”a