Ativan® or lorazepam and Xanax® (alprazolam) are both drugs that belong to a frequently prescribed class of medicines known as benzodiazepines. They have some noted differences. This is evidenced in the way lorazepam and Xanax®, are used in the medical profession and in the way they’re classified.
As a class, benzodiazepines are used as anxiolytics, anticonvulsants, hypnotics and antispasmodics. In other words, they may reduce anxiety, stop seizures, promote sleep, or create muscle relaxation, but not all drugs are used for all things. Lorazepam and Xanax® have one overlapping use; and may both be employed as anxiolytics. Ativan® has an additional use as an anticonvulsant, while alprazolam is not effective in this respect. There appears to be a high degree of preference among prescribing physicians on which benzodiazepines are best for anxiety, and occasionally both drugs are used as hypnotics, though Ativan® is likely to be more effective, and better benzodiazepines exist for sleep problems.
One of the ways that benzodiazepines are compared is by establishing how fast they act and their half-life. They may be separated into groups by when they reach peak serum concentration in the blood and can be called short, medium, and long-acting depending on their half-life. Xanax® is short-acting and lorazepam is in the medium class. Alprazolam has a half-life between six to 12 hours and hits peak serum concentration in one to two hours; lorazepam’s half-life is 10-20 hours, with a peak at two to four hours. Xanax® works faster as an anxiolytic, but lorazepam works longer.
Xanax® may be more appropriately used for occasional anxiety of very short duration, such as the length of a scary plane ride or for a couple of hours prior to a surgery, and many physicians will only prescribe a few pills at a time. Notably, Xanax® has one pronounced medical advantage. Since its clearance is faster, it may be a better choice for patients who are taking many other drugs, because any drug interactions are likely to be of shorter duration. When the goal is providing longer relief for anxiety, the option is to take more doses of Xanax® or to turn to lorazepam because it may provide a longer period of anxiety relief with a single dose.
Another way to evaluate differences between lorazepam and Xanax® is by looking at comparative dose strength. A 0.5 mg dose of Xanax® is roughly equal to a one-milligram dose of lorazepam. This means patients take about twice as much lorazepam as they do alprazolam to achieve approximately the same effect. So essentially, Xanax® is stronger, but still works for a shorter period. To get the same anxiety coverage over 10-20 hours that Ativan® provides, people might need to take more doses of Xanax® since they don’t last as long.
Lorazepam and Xanax® may differ in others ways that are individualized. Side effects are similar but could have small features that are different, and individual patients may find they prefer one of these drugs to the other in terms of effectiveness or lower likelihood of experiencing adverse effects. They also aren’t the only options available in the benzodiazepine class; other comparable anxiolytic and/or anticonvulsive medications include clonazepam, diazepam, and oxazepam.