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BARBITURATES
CHEMISTRYDerivatives of Barbituric acid.
DISADVANTAGES   Low Therapeutic Index   Potent Enzyme Inducers : Drug Interactions   Drug of Abuse   Risk of Physical ...
CLASSIFICATION OF BARBITURATESAccording to duration of actionI.  Long acting barbiturates (DOA: 8-12hrs)          Phenobar...
III.   Short-acting barbiturates (DOA: 2-4hrs)       Quinal barbitoneIV.    Ultrashort Acting (DOA: 15-30 min)       Thiop...
PHARMACOKINETICS
MOAMultiple MOA at multiple sites in brain:1.(a) Acts on GABAA Receptor chloride channel    .Site of action: Different fro...
2.Depress voltage activated Ca+ currents in isolated  Hippocampal neurons.3.Depress Glutamate induced depolarizations.4. I...
GROUP ACTIONS   Sedation   Hypnosis   Antiepileptic   Anticonvulsant   Hyperalgesia   Amnesia & Automatism
   Action on Respiratory System   Action on Liver   Action on GIT   Action on CVS   Action on Kidneys   Action on AN...
THERAPEUTIC USES   Hypnotic   Sedatives   GA   Antiepileptic   Anticonvulsant   Potentiation of Anesthesia   Neonat...
ADVERSE EFFECTS   Hangover   Drug Automatism   Skin rashes   GIT disturbances   Idiosyncracy---Excitation Restlessnes...
DIFFERENCE BETWEEN      BZP&BARBITURATESbENZODIAZEPINES                                 BARBITURATESGABA ergic            ...
Acute Poisoning: Symptoms General Treatment Specific TreatmentDrug Dependance :
CONTRAINDICATIONS   Hepatic failure   Severe pulmonary insufficiency.   Porphyria
Buspiron   Newer selective anti-anxiety agent.   Partial agonist at brain 5HT1AReceptors.   Agonist at brain Dopamine D...
Differences from BDZ:   OOA more than a week. Unsuitable for acute anxiety states.   No marked Sedative, Euphoric & Hypn...
Adverse Effects   Tachycardia   Palpitations   Nervousness   Gastrointestinal distress   Paresthesias   Elevated Blo...
ZOLPIDEMImidazopyridine. St. related to BDZ zaleflon.MOA:- BZ1 – Omega subtype and facilitates  GABA medidated neuronal in...
   Sedative anxiolytic, Hypnotic.   Minimal muscle relaxing and anticonvulsant    effects.   Larger doses produce amnes...
ZALEPLON   Binds to BZ1   Facilitates inhibitory actions of GABA.   Effect on Sleep:-   Less risk of tolerance and wit...
PARALDEHYDE   CYCLIC ETHER   Colorless transparent   Pungent smell
PHARMACOKINETICS   Absorption   Metabolism   Excretion
CLINICAL USES   Orally ___ hypnotic   I/M ____             Mania             Alcohol withdrawal             Anticonvulsa...
TOXICITY1.   GIT upset on oral adm2.   I/M adm – abscess formation3.   Accidental I/V administration       Violent coughin...
4. Administration of expired drug     (or drug exposed to sunlight)           Acetic acid & Acetaldehyde is formed        ...
CONTRAINDICATION   Hepatic & pulmonary impairment   Never given to patients taking Disulfiram     ( Aldehyde dehydrogena...
Barbiturates
Barbiturates
Barbiturates
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Barbiturates

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Barbiturates

  1. 1. BARBITURATES
  2. 2. CHEMISTRYDerivatives of Barbituric acid.
  3. 3. DISADVANTAGES Low Therapeutic Index Potent Enzyme Inducers : Drug Interactions Drug of Abuse Risk of Physical Dependence Svere withdrawal Syndrome
  4. 4. CLASSIFICATION OF BARBITURATESAccording to duration of actionI. Long acting barbiturates (DOA: 8-12hrs) Phenobarbitone Barbitone Methyl phenoborbitoneII. Intermediate acting (DOA: 4-8hrs) Amylobarbitone Butobarbitone Cyclobarbitone Pentobarbitone
  5. 5. III. Short-acting barbiturates (DOA: 2-4hrs) Quinal barbitoneIV. Ultrashort Acting (DOA: 15-30 min) Thiopentone Sodium Methohexital Thiamylal
  6. 6. PHARMACOKINETICS
  7. 7. MOAMultiple MOA at multiple sites in brain:1.(a) Acts on GABAA Receptor chloride channel .Site of action: Different from BDZ & GABA . GABA ergic at low doses. Prolongation of Chloride channel openings. GABA mimetic at high doses. Activate the Chloride channel.
  8. 8. 2.Depress voltage activated Ca+ currents in isolated Hippocampal neurons.3.Depress Glutamate induced depolarizations.4. Inhibition of Na+ channel.--- at high conc. (GA)5. Inhibition of K+ channel.--- at still higher conc. (GA)
  9. 9. GROUP ACTIONS Sedation Hypnosis Antiepileptic Anticonvulsant Hyperalgesia Amnesia & Automatism
  10. 10.  Action on Respiratory System Action on Liver Action on GIT Action on CVS Action on Kidneys Action on ANS Dependence
  11. 11. THERAPEUTIC USES Hypnotic Sedatives GA Antiepileptic Anticonvulsant Potentiation of Anesthesia Neonatal jaundice & Kernictrus In narcoanalysis
  12. 12. ADVERSE EFFECTS Hangover Drug Automatism Skin rashes GIT disturbances Idiosyncracy---Excitation Restlessness Attacks of Ac. Porphyria, Enzyme Induction Megaloblastic anaemia Depression of fetal respiration
  13. 13. DIFFERENCE BETWEEN BZP&BARBITURATESbENZODIAZEPINES BARBITURATESGABA ergic GABAmimetic in large doses Blockade of Ca, Na ,K channels,ih NMDA recCommonly used sedative hypnotic Obsolete for such use Causes hyperalgesia More resp depression may be fata toxic dosesSafe in patients of porphyria CI in porphyriaNo role in neonatal jaundice Ezyme inducer, used in neonatal jaundiceMore commonly used for premedication Ultra –short acting as i/v GA ,forMidazolam for induction inductionFloppy baby syndrome ,if given prior to delivery Pronounced resp depression
  14. 14. Acute Poisoning: Symptoms General Treatment Specific TreatmentDrug Dependance :
  15. 15. CONTRAINDICATIONS Hepatic failure Severe pulmonary insufficiency. Porphyria
  16. 16. Buspiron Newer selective anti-anxiety agent. Partial agonist at brain 5HT1AReceptors. Agonist at brain Dopamine D2 Receptors CLINICAL USE mainly used for GAD
  17. 17. Differences from BDZ: OOA more than a week. Unsuitable for acute anxiety states. No marked Sedative, Euphoric & Hypnotic effect Less psychocntor impairment No Rebound anxiety. No withdrawal signs on abrupt discontinue Minimal abuse liability. No potentiation of other CNS depressants. Elderly patients are not more sensitive to its effects.
  18. 18. Adverse Effects Tachycardia Palpitations Nervousness Gastrointestinal distress Paresthesias Elevated Blood Pressure
  19. 19. ZOLPIDEMImidazopyridine. St. related to BDZ zaleflon.MOA:- BZ1 – Omega subtype and facilitates GABA medidated neuronal inhibition
  20. 20.  Sedative anxiolytic, Hypnotic. Minimal muscle relaxing and anticonvulsant effects. Larger doses produce amnesia. Minor effects on sleep pattern. Suppress REM sleep at higher doeses. Rebound insomnia may occur on abrupt discontinuance. Resp. depression with larger doses. Actions are antagonised by flemazenil Less risk of dependence and tolerance.
  21. 21. ZALEPLON Binds to BZ1 Facilitates inhibitory actions of GABA. Effect on Sleep:- Less risk of tolerance and withdrawal syndrome. Potentiate effects of Ethanol and other sedative Hypnotics.
  22. 22. PARALDEHYDE CYCLIC ETHER Colorless transparent Pungent smell
  23. 23. PHARMACOKINETICS Absorption Metabolism Excretion
  24. 24. CLINICAL USES Orally ___ hypnotic I/M ____ Mania Alcohol withdrawal Anticonvulsant Status epilepticus Tetanus Eclampsia
  25. 25. TOXICITY1. GIT upset on oral adm2. I/M adm – abscess formation3. Accidental I/V administration Violent coughing Pulmonary edema Coma & sudden death
  26. 26. 4. Administration of expired drug (or drug exposed to sunlight) Acetic acid & Acetaldehyde is formed Hypotension Respiratory depression Coma5. Tolerance & addiction6. Over dosage toxicity 1. Acidosis 2. GIT Bleeding 3. Toxic hepatitis 4. Nephrosis
  27. 27. CONTRAINDICATION Hepatic & pulmonary impairment Never given to patients taking Disulfiram ( Aldehyde dehydrogenase inhibitor)

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