In Summary

There are some notable differences between Valium and Xanax, but also some similarities.

• Valium and Xanax are both benzodiazepines that can be used to treat anxiety. Both are equally effective for this use. When taken by mouth, both are quick to have an effect (within half to one hour), although Valium may work slightly more quickly.
• The effects of Valium last around 4-6 hours; however it has a very long half life (20-70 hours - time taken to clear 50% of the drug from the body) which means that it may take up to six weeks to be totally excreted by the body. The effects of Xanax last approximately 5 hours, and with a half life of 11 hours it can take several days to leave the body.
• Studies have shown that people of Asian descent have higher peak levels of Xanax and the effects of Xanax last longer. Duration of effect is also longer in people with concurrent liver or kidney disease, alcoholism or obesity. Experts aren't sure if race or other factors such as smoking influence Valium's effects, although it is possible that some people of Asian or African descent may metabolize Valium more slowly leading to increased effects.
• Valium is more likely than Xanax to cause drowsiness, but Xanax is reported to have more severe withdrawal effects on discontinuation.

See also: Drugs.com Compare Tool - Valium vs Xanax

More detailed information

What are Valium and Xanax?

Valium is a brand name for diazepam and Xanax is a brand name for alprazolam. Although both drugs are benzodiazepines, so have a similar mechanism of action, there are structural differences between them that affect their activity in the body.

Which one works quicker?

Valium may be absorbed slightly faster than Xanax; however, the difference is minimal. Peak concentrations of both usually occur within 1-2 hours. Effects of Xanax last on average 5 hours although there are wide variations between individuals (see below). Effects of Valium last approximately 4 hours, although may persist for longer in some people. One study suggested diazepam may be more effective than alprazolam at controlling anxiety particularly if the person was also depressed; however, the overall difference was not significant.

How much Xanax equals 5mg of Valium?

Benzodiazepine equivalency tables state that 0.5mg of alprazolam (Xanax) is approximately equivalent to 5mg diazepam (Valium). However, people of Asian descent metabolize Xanax differently to people of other races, and certain disease states such as alcoholism, liver and kidney disease, obesity and even old age can affect how Xanax behaves in the body; so benzodiazepine equivalency tables should be used as a guide only as they do not reflect individual variation. Unfortunately, few studies have been done investigating the metabolism of diazepam in people of different enthnic backgrounds. However, researchers do know it is metabolised by the CYP2C19 group of hepatic enzymes. Approximately 15.7% of Asian people and 18.5% of African Americans have a slow metabolizing form of this enzyme. Both Valium and Xanax should only be used short-term due to risk of addiction and dependence.

How do Valium and Xanax work?

Both Valium and Xanax, like all benzodiazepines, enhance the actions of a neurotransmitter in the brain called GABA (gamma-aminobutyric acid). This neurotransmitter can reduce the activity of nerve cells, so enhancing it has a calming effect which can improve symptoms of anxiety, reduce muscle tension, stop seizures, and induce sleep. Benzodiazepines are also known for their amnesic effect – or ability to disrupt short-term memory – and this makes them useful before surgery. Because of structural differences, some benzodiazepines are more likely than others to make you sleepy, relieve anxiety, stop seizures, relax muscles, or make you forget. Valium and Xanax are both FDA approved for anxiety-relief, but Xanax is less likely than diazepam to induce sleep. Diazepam may also be used in the treatment of seizures, in anesthesia, and as a muscle relaxant.

Which drug is more effective for anxiety?

A trial that directly compared Valium with Xanax for the treatment of anxiety reported Valium to be slightly more beneficial than Xanax at relieving anxiety, particularly if the anxiety was also accompanied by depression, but the differences were unlikely to be clinically meaningful. Few side effects were reported, the more common ones were drowsiness, tremor, light-headedness, and dry mouth. One allergic-type reaction was reported with Xanax. Other studies suggest Xanax is less likely to cause drowsiness than diazepam.

Which drug is more addictive or has more withdrawal reactions?

Generally speaking, benzodiazepines with a shorter half life (such as Xanax) are harder to stop than those with a longer half life (such as Valium). Both drugs readily enter brain tissue which reinforces drug taking and is generally associated with more severe withdrawal symptoms. Some experts advise Xanax to be used with caution as it has been associated with more severe withdrawal symptoms compared with other benzodiazepines.