Question: how long does it take to feel effects of ativan?
Answer: How long does it take to work? Lorazepam tablets and liquid start to work in around 20 to 30 minutes. It reaches full sedating effect after 1 to 1.5 hours and lasts for around 6 to 8 hours. A lorazepam injection works much faster but also lasts around 6 to 8 hours.