Ativan has a half-life of hours on average, so withdrawal symptoms can start relatively quickly (within 24 hours) following the last dose. The average onset. Oxazepam is one of the active products of metabolism from diazepam. Other side effects are similar to those for other members of this drug group. Oxazepam provided a more rapid onset of action but a significantly greater number of adverse . Medications such as benzodiazapenes, sertraline, topiramate, melatonin. Only your healthcare provider can determine the length of lorazepam treatment that is right for Any medication side effects you may have experienced in the past or are currently The onset of action usually occurs within 20 to 60 medicalcases.eug: melatonin.