Similarities and differences between Lorazepam and Diazepam

Many people around the globe are using Lorazepam and Diazepam for sleep and anxiety disorders but not everyone knows the similaraties and differences between them. Both these medications are benzodiazepines and help in calming the brain by affecting the central nervous system. But there are differences in their half lives and duration of action. In this guide, we will talk about the similaraties and differences between Lorazepam and Diazepam along with their effectiveness and strength.

Lorazepam vs Diazepam

Let’s first talk about the similarities of both these drugs;


Both Lorazepam and Diazepam belong to the same class of drugs which is benzodiazepine which means that both of these drugs work on the neurotransmitter gamma aminobutyric acid to produce a calming effect in the brain like other benzodiazepine drugs.

What is Lorazepam and Diazepam used for?

These drugs are prescribed by doctors to manage and treat anxiety, and panic attacks, and are also used as adjuncts in the treatment of seizures and muscle spasms.

Time of action

Both of these benzodiazepine drugs have a relatively quick time of action which is why they are considered a suitable option to manage acute anxiety and panic attacks.

Treatment of similar disorders

Lorazepam and Diazepam are both benzodiazepine drugs and follow the same mechanism to calm down the brain activity by affecting GABA that’s why they mostly treat similar disorders;

Treat anxiety disorders

These drugs are most commonly used to treat anxiety symptoms and other disorders such as;




Treat alcohol withdrawal syndrome

Side Effects that are similar

Lorazepam and Diazepam both being benzodiazepines have similar mechanism of action and hence similar side effects. However, these side effects can vary among different individuals using them.

There may be symptoms of these drugs but it is mandatory to use these drugs under the supervision of your doctor to manage and avoid these withdrawal symptoms. It is also important to note that these drugs are prescription medication and cannot be bought and used without a valid prescription by a certified doctor in order to prevent its potential for dependency and tolerance. The common side effects of these two drugs are as follows;


Both these medications can cause minor drowsiness but it turns alarming if you feel extreme drowsiness. Due to this drowsiness, it is prohibited to do concentration required activities like driving and using heavy machinery.

Sedative effects

As the function of both of these drugs is to cause sedation it is common to feel sedation after taking any of these medicines. This calming effect can affect your cognitive and motor function but it is normal with these drugs until it turns into faintness. But in case of increased sedation consult your doctor.


Feeling light dizziness is also a similar and common side effect with these drugs which causes the risk of falling or accident so doctors prescribe rest with these medications.

Cognitive impairment

As all benzodiazepines both Diazepam and Lorazepam cause cognitive problems like memory problems, difficulty in concentrating, confusion, and slurred speech so it’s better to sleep for long after taking this medication.

Muscle weakness

Muscle weakness and tiredness are also common side effects of these drugs noticed in users.

Gastrointestinal issues

Gastro issues like nausea, constipation, and changes in appetite are possible side effects of two drugs. In case any of these problems get worse visit your doctor to consult what to do with such serious side effects.

Tolerance and dependence

Long term use of any of these two drugs can prove havoc because there is a high risk of tolerance development and dependency of the drug in your body. And in the case of Diazepam, it is even worse because it can lead to the development of tolerance which will require even higher doses to resolve the tolerance and this will ultimately cause dependence on the drug. After dependence when you stop taking Diazepam after such a prolonged and high dosage, it can cause severe withdrawal symptoms.

Rebound anxiety and insomnia

When a patient stops taking these drugs he may experience a temporary worsening of anxiety or insomnia as a withdrawal symptom. You can consult your doctor in this case for better administration.

Respiratory depression

If an individual takes high doses of any of these two drugs or combines it with non-interactive interaction such as any other sedative medicine or alcohol, it can cause a serious risk of respiratory depression. This worsening side effect may lead to your death.

Paradoxical or opposite adverse reactions

In some cases, rather than producing a calming effect, these drugs can cause to increase agitation and anxiety or cause a person to behave abnormally. This case requires a doctor to immediately resolve the reaction of the drug with inhibitors.

Other drug interactions of Lorazepam and Diazepam

Both of these drugs can interact with other medications, foods, and drinks. These two drugs mostly interact with the same sedatives, antibiotics, anti-allergies, anti-depressants, and other medicines. To avoid these fewer unfavorable interactions consult your doctor before using any of the prescription drugs.


Half life differences

When it comes to half-life Diazepam has a longer half-life of about 48 hours and to talk about Ativan Lorazepam has a shorter half-life and stays in human plasma for about 12 hours. This difference shows that Diazepam stays for a longer time in the body of a patient and has a longer duration of action than Lorazepam. 

Potency or dosage difference 

Diazepam is more potent than Lorazepam as a lower dose of Diazepam can achieve the similar effects to that of a higher dose of Lorazepam. 

Central difference in metabolism of the two drugs interact

There is also a difference in the metabolism of both of these drugs as Lorazepam is metabolized in the liver while Diazepam is metabolized into active metabolites which prolongs its effects. 

Difference disorders these drugs treat

Being benzodiazepine medications both Lorazepam and Diazepam treat almost similar disorders but there are some specific conditions that only Diazepam can treat and Lorazepam is not typically prescribed for those conditions, such as,

1-      Diazepam is used to relieve muscle spasms, muscle stiffness, and certain types of muscle pains that are associated with muscle injuries or neurological disorders. However Lorazepam is not commonly prescribed in such conditions.

2-      Diazepam is sometimes used in managing the alcohol withdrawal symptom syndrome and alcohol withdrawal seizures to calm down the central nervous system during the process. While Lorazepam may also be used for this purpose normally Diazepam is considered more effective in treating this condition due to its longer duration of action.

3-      Diazepam is used to treat acute seizures and status epilepticus as it is a prolonged and life-threatening seizure. Diazepam being rapidly active is given to the patient intravenously or rectally for rapid control. Lorazepam is not used in this condition for being slower than Diazepam but it may be used in treating long-term seizure management.

4-      Diazepam is sometimes given as a muscle relaxant in the treatment of Tetanus in which a serious bacterial infection affects the nervous system and causes severe muscle stiffness and spasm.

It is to note here that while Diazepam may be used in these conditions still its use should be always guided by a healthcare provider due to the potential side effects.

Switching from Diazepam to Lorazepam - The things Important to note to avoid withdrawal symptoms

Switching from Diazepam to Lorazepam is necessary to be done under the supervision of a health specialist and a specific clinical situation. This transition is mandatory to be managed by a healthcare provider due to the differences in the half lives, potency, and metabolism of these two drugs. 

It is important to gradually taper the dose of the current medication and introduce the new drug under the supervision of your doctor or pharmacist to prevent withdrawal symptoms and to ensure a smooth transition. The specific approach and timeline of this medication transition depends upon individual factors and responses of the patient. These individual factors may vary in every case. 

Which is stronger Lorazepam or Diazepam?

Diazepam and Lorazepam both differ in potency and time of action but Diazepam is considered stronger in potency than Lorazepam. This means that a smaller dose of diazepam can achieve similar effects as a higher dose of Lorazepam can achieve. For example, as a sedative 500mg Lorazepam is equivalent in action to just 10mg Diazepam.  

Along with anxiety treatments, the use of Lorazepam and Diazepam as surgical premedication with anesthesia is also considered excellent for releasing anxiety and agitation before surgery.

But the time of action of these drugs differs both in surgical premedication and in general use. If you take Diazepam through iv its clinical effects and sedation peak in 2 to 3 minutes and on the other hand Lorazepam has a latent period of 8 to 15 minutes and sometimes increases to 15 to 30 minutes depending on the patient’s body specificity.

While on the other hand, when you take these drugs orally or intramuscularly their time of action differs a lot. Lorazepam takes up to 60 minutes when taken intramuscularly and around 90 minutes when taken orally. Similarly, Diazepam as being faster than Lorazepam has an onset dosage action speed of around 15 to 60 minutes and this effect lasts for about 12 hours which is longer than Lorazepam.  

However, the choice of drug depends on the patient’s specific needs, response, and the condition being treated.

Which is more effective Diazepam or Lorazepam?

When it comes to the effectiveness of Lorazepam and Diazepam, it totally depends on the condition of the patient’s body, age, and disorder. Diazepam’s longer half life may make it more suitable for manage acute anxiety disorders and severe seizure problems. But on the other hand, Lorazepam is proved to be more effective in managing chronic panic attacks or frequent anxiety episodes, or alcohol withdrawal symptoms without any prolonged stay of medicine in the body.

Basically, Diazepam is normally used to treat acute problems that require instant relief and Lorazepam is used for chronic conditions that require long-term treatment.

However, it cannot be decided that which drug is better for your condition without the help of your medical practitioner’s advice. Only your doctor can decide that which of these medications will work better with your condition.  

To conclude the discussion about the similarities and differences between Diazepam and Lorazepam we can say that both these drugs have their own strengths and weaknesses, and the choice between them should be based on proper medical guidance, where a doctor will measure the individual needs and specific clinical context of the patient.

It is mandatory to consult your doctor or pharmacist to determine which drug is most appropriate for your condition and to ensure safe transition if switching from one to an other. It is also necessary to take your health care provider’s advice before leaving these drugs as if left without a tapper process these drugs can cause severe side effects. This is why it for these drugs to not be discontinued abruptly.

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