May 26, - combination of Ativan and alcohol can cause instant blackouts and in patients who received treatment for serious injuries, including those. Side-Effects Of Ativan With Alcohol. Drowsiness. Dizziness. Increased Risk for Overdose. Slowed or Difficulty Breathing. Impaired Motor Control. Unusual Behavior. Memory Problems. Jun 28, - Mixing lorazepam and alcohol can cause memory loss, loss of inhibition and irritability. rehab program options in our comprehensive outline of lorazepam addiction treatment programs. .. Most times to blackout point.