Ativan (lorazepam) most commonly causes sedation, dizziness, weakness, and unsteadiness. In clinical trials of roughly 3,500 patients, about 16% experienced sedation, making it by far the most reported side effect. These effects stem from how the drug works: it amplifies your brain’s natural calming signals, which slows activity across your entire nervous system, not just the parts tied to anxiety.
The Most Common Side Effects
The FDA label for Ativan reports these rates from clinical trials involving anxiety patients:
- Sedation: 15.9%
- Dizziness: 6.9%
- Weakness: 4.2%
- Unsteadiness: 3.4%
Sedation is the side effect you’re most likely to notice first. Ativan works by boosting the activity of GABA, your brain’s primary “slow down” chemical. When GABA receptors are activated more strongly, nerve cells become less excitable across broad areas of the brain. That calms anxiety, but it also dampens alertness, coordination, and muscle tone. The drowsiness, the wobbly feeling, and the muscle weakness are all different expressions of the same underlying mechanism.
These common side effects tend to be strongest when you first start taking the medication or when your dose increases. Some people also report mild memory difficulties, particularly trouble forming new memories while the drug is active in the body.
How It Affects Driving and Reaction Time
Ativan measurably slows reaction time and processing speed. Multiple randomized trials have shown that benzodiazepines impair performance on tests designed to measure the brain functions used while driving. The drug’s effects on brain wave activity remain elevated for at least eight hours after a single dose, meaning impairment lasts longer than most people expect.
One important finding: feeling alert again does not mean you’re safe to drive. Research on long-term benzodiazepine users found that driving test performance didn’t return to normal until about three years of consistent use, even though the subjective feeling of drowsiness wore off much sooner. Cognitive test results stayed abnormal even after driving performance recovered. The gap between feeling fine and actually being unimpaired is real and worth taking seriously.
Paradoxical Reactions
In roughly 1% of people, Ativan produces the opposite of its intended effect. Instead of calm, these individuals experience agitation, irritability, aggression, or significant behavioral disturbance. These paradoxical reactions are more commonly reported in children and older adults, though they can happen to anyone. If you notice increased hostility or restlessness after taking Ativan, that’s a recognized reaction pattern, not just a bad day.
Risks Specific to Older Adults
People over 65 face a distinct set of concerns with Ativan. The American Geriatrics Society lists all benzodiazepines, including lorazepam, on its Beers Criteria, a widely used guide to medications that are potentially inappropriate for older adults. The reasons are specific: older adults metabolize these drugs more slowly, their brains are more sensitive to the sedating effects, and the consequences of impairment are more severe.
All benzodiazepines increase the risk of cognitive impairment, delirium, falls, fractures, and car crashes in older adults. Shorter-acting benzodiazepines like Ativan are not safer than longer-acting ones when it comes to fall risk. For people with dementia or existing cognitive impairment, the recommendation is to avoid benzodiazepines entirely due to their effects on the central nervous system. The continued use of benzodiazepines in older adults may also lead to clinically significant physical dependence.
The Danger of Mixing With Alcohol or Opioids
Combining Ativan with alcohol is one of the most dangerous things you can do with this medication. Both substances amplify GABA activity in the brain, and together their effects don’t just add up, they become overpowering. Alcohol intensifies benzodiazepine sedation, worsens balance, slows reaction time further, and increases the risk of confusion, fainting, and respiratory depression. Respiratory depression, where breathing becomes dangerously slow or shallow, is the primary way this combination becomes fatal.
The FDA has placed a boxed warning (the most serious warning category) on all benzodiazepines regarding their use with opioids. Combining these drugs with opioid pain relievers, alcohol, or other sedating substances can cause severe respiratory depression and death. This warning also applies to people taking medications for opioid addiction, though stopping those medications isn’t recommended either. The risk requires careful management rather than avoidance of treatment.
Dependence and Withdrawal
Physical dependence can develop with regular Ativan use, even at prescribed doses. Your brain adapts to the increased GABA activity by becoming less responsive to it over time. This is tolerance, and it can begin after just a few doses. Once dependence sets in, stopping the drug abruptly can trigger withdrawal symptoms that range from rebound anxiety and insomnia to more serious reactions like seizures.
The FDA’s updated boxed warning specifically addresses this: abuse, addiction, physical dependence, and withdrawal reactions are recognized risks of all benzodiazepines. Ativan has a half-life of roughly 14 hours, meaning it takes about that long for half the drug to leave your body. That relatively short window means withdrawal symptoms can begin within a day of the last dose for someone who is physically dependent. Tapering off gradually under medical guidance is the standard approach to discontinuation.
Signs of Overdose
Ativan overdose looks like an extreme version of its normal side effects: profound fatigue, loss of coordination, involuntary muscle spasms, confusion, and difficulty staying conscious. The threshold for overdose varies by person and depends on weight, age, metabolic rate, tolerance, and whether other substances are involved. Any amount above what was prescribed can potentially cause overdose.
The most dangerous symptom is respiratory depression. A fatal overdose from Ativan alone is less common than overdose involving multiple substances, but a non-fatal overdose can still become life-threatening if slowed breathing isn’t recognized and treated. Difficulty waking someone up, very slow or shallow breathing, and a bluish tint to lips or fingertips are emergency signs.