If it only contained penicilin, an no other atibiotic, or active ingredient, there is no need to avoid alcohol. The ones I can find listed in my Stockly's Drug interactions, granted now a little out of date are cephelosporins, griseofulvin and possibly doxycycline and erythromycin.
I can't find anything listed that sugests it will take the drugs longer to clear from the system, there is one paper that suggests that it might clear the drugs faster, but not penicillin