What Is the Difference between Diazepam and Lorazepam?

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  • Written By: Alex Newth
  • Edited By: Angela B.
  • Last Modified Date: 27 January 2019
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Diazepam and lorazepam are two prescription drugs that belong to the benzodiazepine family. Both are used to treat similar conditions, such as anxiety and insomnia, and both are stored in the same way. The primary differences come from the strength of the benzodiazepine, the rate at which the drugs metabolize, their interaction with other substances, side effects, and their effect on nursing mothers.

These two drugs have different strengths and, as a result, are prescribed at different dosage levels. Diazepam is typically prescribed in dosages ranging from 2mg to 10mg, and is the weaker of the two. Lorazepam is typically prescribed in dosages from 2mg to 4mg. Both drugs are to be taken two to four times a day, according to the instructions of a healthcare professional. The dosage amount is also determined by the medical professional and depends on the patient’s health, among other factors.

When diazepam is metabolized, it first goes through the liver and then is excreted by the kidneys. Patients with kidney abnormalities may need lower dosages, because diazepam can affect the kidney during this process. Lorazepam metabolizes much faster than any other benzodiazepine and, because of this, there is a lower chance that it will linger in the blood and become toxic. Abusing lorazepam, though, can still cause blood toxicity.


Both diazepam and lorazepam interact with other substances, most commonly alcohol, narcotics, barbiturates, and tranquilizers. The effects suffered from this interaction are worse with diazepam, which also interacts with a wider range of substances and medications. The only drugs that have been shown to have a powerful interaction with lorazepam are drugs containing loxapine. This interaction causes a stronger, and more prolonged, sedating effect that can become dangerous or fatal.

These drugs can both cause sedation, weakness, feelings of lightheadedness, and dizziness. Diazepam has more side effects than lorazepam, including excitability, the inability to sleep, rage, spasms, speech problems, and double vision, though these extra side effects are rare.

Some medications can transfer from a nursing mother's bloodstream into her breast milk to be passed on to her baby. Tests on diazepam have shown that it does excrete via breast milk and, therefore, diazepam should not be used by nursing mothers. Similar tests on lorazepam have been inconclusive, so mothers should still be cautious when nursing.


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Post 5

I'd say that it's a rather important difference that, "The primary differences come from the strength of the benzodiazepine, the rate at which the drugs metabolize, their interaction with other substances, side effects, and their effect on nursing mothers."

As to habituation, there are a host of illness for which the benzodiazepines are not only effective, but the safest.

Post 4

Get with it, people. Valium is the longest acting Benzo. Lorazepam is a stronger substance than Diazepam, which is why you get lower doses. Both are habit forming, mind screwing drugs and should only be taken for two or three weeks at the most.

Post 3

Lorazepam versus diazepam, which causes the least side-effects?

Post 2

@anamur-- Lorazepam does stay in the system longer, but that can be both a good thing and a bad thing.

The good part is that you don't need to take such a high dose of lorazepam to experience its effects for a longer period. Diazepam has a shorter life like you said and so it will require a higher dosage for the effects to last longer.

But both of these are addictive drugs, so I don't think that one is necessarily better than other.

Post 1
Lorazepam is stronger than diazepam, but I've also noticed that its effects wear off faster than diazepam.

I've been on both of these medications and I had a more difficult time withdrawing from diazepam than I did from lorazepam. I had many adverse side effects while reducing the dosage. Ending my lorazepam treatment was much easier and quicker.

So if I had to choose between lorazepam and diazepam, I would choose lorazepam for sure.

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