* After studying this topic, attempt a test on DIAZEPAM under the category ‘TEST FOR YOU: TOPIC-WISE on the TEST PACKAGES page.
This blog prepares you for
GPAT
D.Pharm, B.Pharm, and Pharm.D. (Pharmacy Exams)
RRB Pharmacist Recruitment Exam
Common Recruitment Examination for AIIMS Pharmacist
KGMU Pharmacist Recruitment Exam
KSSSCI Pharmacist Recruitment Exam
MPESB Pharmacist Recruitment Exam
Drugs Inspector Exams
Drugs Controller Exams
DPEE
Diazepam is a CNS depressant drug.
It is used as anxiolytic, hypnotic - sedative, centrally acting muscle relaxant, preanaesthetic agent, anaesthetic and for emergency control of seizures.
It is used to control status epilepticus.
Status epilepticus is a single seizure lasting more than 5 minutes, or repeated seizures without recovery of consciousness.
Chemically, diazepam belongs to benzodiazepine class of drug.
It is a long acting benzodiazepine hypnotic-sedative drug. Its half-life is more than 12 hours.
The ring A of diazepam exhibits π – π stacking with the aromatic amino acid residues of the GABAA receptor. The carbonyl group (−C=O) at position 2 interacts with histidine residue of GABAA receptor. (See structure)
Benzodiazepines are metabolized in liver mainly by CYP3A4 and CYP2C19.
Its metabolites - desmethyl diazepam, oxazepam are active metabolites.
Upon IV administration, it causes analgesia.
It decreases nocturnal gastric secretion and prevents stress ulcers. (Nocturnal means at night time during sleep).
Contraindications for diazepam: Respiratory depression, myasthenia gravis, sleep apnoea, chronic psychosis.
It occurs as a white or pale yellow crystalline powder. It is odourless or almost odourless and tasteless at first followed by bitter taste.
Storage Condition: It should be stored in a tight, light resistant container at 15 – 30 degree C.
Brand names of diazepam: Calmpose, Valium, Placidox, Anaxol, Quietal, Diazewok, Zepose.
Flumazenil is commonly used as an antagonist for the GABAA receptor. Its primary clinical use is to reverse benzodiazepine overdose and sedation.
Mechanism of Action of Diazepam
Mechanism of action of benzodiazepines includes binding to BZD site on the postsynaptic GABAA receptor in different regions of the central nervous system, e.g. brain and spinal cord thereby, increasing the inhibitory effects of GABA.
It is noted that benzodiazepines do not have GABA mimetic action.
They support GABA and increase chloride conductance.
Benzodiazepines enhance frequency of chloride channel opening whereas barbiturates enhance lifetime of chloride channel opening.
MCQs
1. Select correct statements from the following regarding mechanism of action of diazepam.
I) Diazepam has GABA mimetic action
II) It enhances lifetime of chloride channel opening.
III) It binds to BZD site on the postsynaptic GABAA receptor.
IV) It decreases chloride conductance.
a) Only III b) Only I c) II and III d) III and IV
2. Select enzymes involved in the metabolism of diazepam:
I) CYP3A4
II) CYP2C19
III) Aldehyde dehydrogenase
IV) Sulfotransferase
a) I and II b) Only I c) I, II and III d) I, II, III and IV
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Blog content and MCQs have been taken from the following:
1) Essential Pharmacy Review for Drugs Inspector Exams by Nirali Prakashan, Pune
To know more about the book:
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2) Pharmacist Recruitment Exam by Nirali Prakashan, Pune
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