Difference Between Clonazepam and Lorazepam


Main Difference

The main difference between Clonazepam and Lorazepam is that Clonazepam is used to treat the seizure disorders and Lorazepam is used to treat anxiety disorder.

Clonazepam vs. Lorazepam

Clonazepam has hydrogen at carbon number 3 of the diazepine ring while Lorazepam has hydroxyl group attached to carbon number 3 of the diazepine ring. Clonazepam has nitro group attached as R7 of a benzene ring, on the other hand, Lorazepam has a chloride group attached as R7 of the benzene ring. Clonazepam is a long-acting benzodiazepine, and its duration of action is 1-3 days while Lorazepam is intermediate-acting benzodiazepine with the duration of action of the 11-20 hrs. Clonazepam has more selective anticonvulsant activity, whereas Lorazepam has less selective anticonvulsant activity. Clonazepam in nonsedative doses causes muscle relaxation while Lorazepam does not cause muscle relaxation in nonsedative doses. Clonazepam is not used as anesthetic adjuvant while Lorazepam is used as an anesthetic adjuvant. Clonazepam antagonizes the pentylenetetrazol effects in unusual dose; on the other hand, Lorazepam does not antagonize the pentylenetetrazol effects. Clonazepam tolerance develops in patients after 1-6 months of treatment and after which the patient does not show response to any dose of it while in Lorazepam tolerance develops soon.


Comparison Chart

Clonazepam is a long-acting benzodiazepine which facilitates GABAergic transmission.Lorazepam is intermediate acting benzodiazepine which facilitate GABAergic transmission.
Receptors at Which Drug Acts
Clonazepam acts at GABA receptors.Lorazepam also acts at GABA receptors.
Mode of Action
Clonazepam acts at agonist at GABA receptors.Lorazepam acts at agonist at GABA receptors.
Therapeutic Uses
Anticonvulsant, AntiepilepticAnxiety, Status epilepticus
Effect on Respiratory System
Clonazepam causes respiratory depression when given intravenously.Lorazepam causes respiratory depression when given intravenously.
Effect on Cardiovascular System
Clonazepam causes cardiovascular depression when given intravenously.Lorazepam cardiovascular depression when given intravenously.
Available Dosage Forms
Oral, ParenteralOral, Parenteral
Closed-angle glaucoma, Wide angle glaucoma, PorphyriaHypersensitive patients of benzodiazepines, Acute narrow-angle glaucoma
Adverse Effects
Dizziness, Tiredness, Loss of coordination, Increased salivaFatigue, Amnesia, Memory impairment, Confusion, Depression

What is Clonazepam

Clonazepam is the benzodiazepine used to treat the different types of seizures. The different type of seizures includes myotonic or atonic seizures. Clonazepam is also used to treat photosensitive epilepsy and absence seizures. Tolerance is the problem in the use of clonazepam as tolerance develops when clonazepam is used to treat seizures. Clonazepam acts by enhancing the response of gamma-aminobutyric acid receptors. Clonazepam use is also categorized under drug abuse. Clonazepam can be used alone or in combination with other drugs for the treatment of the Lennox-Gastaut syndrome. Clonazepam is given orally for seizures disorders. Clonazepam decreases the generalized the convulsions produced by the stimulation of the amygdala, but it does not abolish unusual discharge at the stimulation site. Clonazepam causes drowsiness and lethargy. Clonazepam also causes muscular intoxication and ataxia. Clonazepam metabolism is mainly by reduction of the nitro group. Clonazepam has a half-life of 1 day.


Examples of famous brands containing Clonazepam is Klonopin.

What is Lorazepam

Lorazepam is the benzodiazepine, which is used to treat anxiety disorders and to produce a calming effect. Lorazepam acts both on brain and nerves, so it is used in anesthesia as an adjuvant. Lorazepam is also used to treat insomnia and anterograde amnesia. Lorazepam shows some effects of narcotic. Lorazepam is rapidly absorbed when given orally. In case of renal or hepatic impairment, the dose of lorazepam is adjusted Lorazepam can also be used as a replacement of some drugs, like lorazepam, can be used to treat agitation when haloperidol is not available. When given with alcohol, narcotics, psychoactive substances it acts synergistically so it should not be prescribed with narcotics or psychoactive agents. Lorazepam also has the problem of tolerance and dependence. Lorazepam metabolism is mainly by conjugation with glucuronic acid. The half-life of Lorazepam is approximately 14 hrs.


Examples of famous brands containing lorazepam are Ativan.

Key Differences

  1. Clonazepam is long-acting Benzodiazepine while Lorazepam is intermediate-acting Benzodiazepine.
  2. Clonazepam is used to treat seizures. On the other hand, lorazepam is used to treat anxiety.
  3. Clonazepam has a half-life of 1 day, on the other hand, the half-life of Lorazepam is approximately 14 hrs.
  4. Clonazepam is useful in the treatment of absence seizures and myoclonic seizures in children while Lorazepam is useful in the treatment of the status epilepticus both in children and adults.


The conclusion of the above discussion is that both Clonazepam and Lorazepam are benzodiazepine agonists, which differ slightly in their therapeutic uses. Both find their roles in changing the neural transmission at GABA receptors.

Janet White

Janet White is a writer and blogger for Difference Wiki since 2015. She has a master's degree in science and medical journalism from Boston University. Apart from work, she enjoys exercising, reading, and spending time with her friends and family. Connect with her on Twitter @Janet__White