Ativan pills come in 0.5 mg, 1 mg and 2 mg doses. Ativan tablets are round and white. Liquid Ativan is generally formulated as 2 mg and is taken orally.Occasionally this medication may be used to treat nausea this can be helpful if you're right about to do something that triggers anxiety. Xanax and Ativan tablets both tend to take 1 to 2 hours to take full effect. However, some people say they start feeling some effects within about 30 minutes.