Lorazepam (Ativan) and Clonazepam (Klonopin) are both strong benzodiazepines with fairly short half lives. Clonazepam has a half life of about 8-10 hours, while Lorazepam is slightly shorter with a 4-6 hour half life. Compared to the longest acting half life benzo such as Valium (Diazepam) which is 80-200 hour half life, both are 10-20 times stronger.