Introduction: SEDATIVES CNS depressant drugs , reduce excitement & tension, & produce calmness & relaxation. HYPNOTICS drugs that produce sleep similar to that of natural arousal sleep. Both sedative & hypnotic action may reside in the same drug. A small dose may act as sedative, whereas a large dose of the same drug may act as a hypnotic. SAR of Benzodiazepine: Presence of phenyl ring / pyridyl ring promotes sedative-hypnotic activity at C5-position. If presence of electron withdrawing group like –Cl or –NO2 (Lorazepam, Clonazepam) at R2’ position, then sedative-hypnotic activity . Presence of electron withdrawing group like –Cl, -F, –NO2 at C7 position, activity. Substitution at 6,8,9 position of carbon atom, activity. Shifting of double bond present between –N4 & C5 or saturation of double bond activity. R3 = alkyl group, activity & R3 = -OH or –COOH activity & R1 = -CH3 ,if larger group is present activity. Sleep is mainly loss of consciousness. Sleep is an architectured cyclic process. These drugs maintains the sleep-wake cycle. Insomnia is a symptom & its proper treatment depends on finding the cause of sleeplessness. To treat this type of patient, use sedative-hypnotics. High dose of the drugs may lead to coma or death.

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2. Benzodiazepines as Sedative -
Hypnotic

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Introduction:
 SEDATIVES CNS depressant drugs , reduce
excitement & tension, & produce calmness & relaxation.
 HYPNOTICS drugs that produce sleep similar to
that of natural arousal sleep.
 Both sedative & hypnotic action may reside in the
same drug.
 A small dose may act as sedative, whereas a large
dose of the same drug may act as a hypnotic.

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 Structure:
1. 1,4-benzodiazepines
Drug
Name
R1 R2 R3 R7 R2
’
Diazepam -CH3 =O -H -Cl -H
Prazepam -CH2- =O -H -Cl -H
Oxazepam -H =O -OH -Cl -H

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 Structure:
2. Triazolobenzodiazepines
Drug
Name
R R1
Alprazolam -CH3 -H
Triazolam -CH3 -Cl
Estazolam -H -H

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 Structure:
3. Imidazobenzodiazepines
e.g.
Midazolam Loprazolam

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6

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 Conclusion:
 Sleep is mainly loss of consciousness. Sleep is
an architectured cyclic process.
 These drugs maintains the sleep-wake cycle.
 Insomnia is a symptom & its proper treatment
depends on finding the cause of sleeplessness. To
treat this type of patient, use sedative-hypnotics.
 High dose of the drugs may lead to coma or death.

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Marketed Benzodiazepine drugs:

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 References:
 D. Sriram & P. Yogeeswari, Medicinal Chemistry, 2nd Ed.,
Pearson, Sedatives, Hypnotics, & Anxiolytic Agents,
Benzodiazepines, Page no.: 129-151.
 KD Tripathi M.D., Essentials of Medical Pharmacology, 7th
Ed., Jaypee Brothers Medical Publishers (P) Ltd., Sedative-
Hypnotic, Benzodiazepines, Page no.: 397-410.

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