The purpose of this study was to evaluate the effect of changing dimensions on the hardness (H), disintegration time (DT), and wetting time (WT) of fast-disintegrating epinephrine tablets for sublingual administration as potential first aid treatment for anaphylaxis. Tablet formulations I and II, containing 0% and 10% epinephrine bitartrate, respectively, and weighing 150 mg were prepared by direct compression. Formulations were compressed at a range of forces using an 8/32'' die with concave punches (CP); a 10/32'' and an 11/32'' die with CP and flat punches (FP). Tablet weight variation, content uniformity, thickness, H, DT, and WT were measured. The 8/32'', 10/32'', and 11/32'' dies resulted in tablet thickness of ranges 0.25-0.19'', 0.17-0.1'', and 0.16-0.08'', respectively. The DT and WT using the 8/32'' die were<or=10 and<or=30 sec, respectively, at H<or=5.4+/-0.2 kg for formulation I, and H<or=5.4+/-0.3 kg for formulation II. The DT and WT were<or=10 and<or=30 sec, respectively, using 10/32'' die/CP, 10/32'' die/FP, 11/32'' die/CP, and 11/32'' die/FP at H<or=6.2+/-0.6 kg, <or=6.8+/-0.4 kg, <or=4.9+/-0.1 kg, and<or=7.2+/-0.3 kg, respectively, for formulation I. For formulation II, the DT and WT were<or=10 sec and<or=30 sec, respectively, when H<4 kg. No difference in DT and WT was observed between concave and flat tablets. The 11/32'' and 10/32'' dies resulted in more ideal tablet dimensions for sublingual administration, but H must be maintained<4 kg to ensure rapid DT and WT.