Anxiolytics............care of the patient and side effects

Anxiolytics

1. SEDATIVE/HYPNOTICS
ANXIOLYTICS
Martha I. Dávila-García, Ph.D.
Howard University
Department of Pharmacology

2. Sedated
Optimal
Performance
Nervous
Breakdown
P
e
r
f
o
r
m
a
n
c
e
Anxiety
GOAL

3. Manifestations of anxiety:
•Verbal complaints. The patient says he/she
is anxious, nervous, edgy.
•Somatic and autonomic effects. The patient
is restless and agitated, has tachycardia,
increased sweating, weeping and often
gastrointestinal disorders.
•Social effects. Interference with normal
productive activities.

4. Pathological Anxiety
Generalized anxiety disorder (GAD): People suffering
from GAD have general symptoms of motor
tension, autonomic hyperactivity, etc. for at least
one month.
Phobic anxiety:
Simple phobias. Agoraphobia, fear of animals, etc.
Social phobias.
Panic disorders: Characterized by acute attacks of
fear as compared to the chronic presentation of
GAD.
Obsessive-compulsive behaviors: These patients
show repetitive ideas (obsessions) and behaviors
(compulsions).

5. Causes of Anxiety
1). Medical:
a)Respiratory
b)Endocrine
c)Cardiovascular
d)Metabolic
e)Neurologic.

6. Causes of Anxiety
2). Drug-Induced:
–Stimulants
•Amphetamines, cocaine, TCAs, caffeine.
–Sympathomimetics
•Ephedrine, epinephrine, pseudoephedrine
phenylpropanolamine.
–Anticholinergics\Antihistaminergics
•Trihexyphenidyl, benztropine, meperidine
diphenhydramine, oxybutinin.
–Dopaminergics
•Amantadine, bromocriptine, L-Dopa,
carbid/levodopa.

7. Causes of Anxiety
–Miscellaneous:
•Baclofen, cycloserine, hallucinogens,
indomethacin.
3). Drug Withdrawal:
•BDZs, narcotics, BARBs, other
sedatives, alcohol.

8. Anxiolytics
Strategy for treatment
Reduce anxiety without causing sedation.

9. Anxiolytics
1)Benzodiazepines (BZDs).
2)Barbiturates (BARBs).
3)5-HT
1A receptor agonists.
4)5-HT
2A, 5-HT
2C & 5-HT
3 receptor
antagonists.
If ANS symptoms are prominent:
•ß-Adrenoreceptor antagonists.

2-AR agonists (clonidine).

10. Anxiolytics
•Other Drugs with anxiolytic activity.
–TCAs (Fluvoxamine). Used for Obsessive
compulsive Disorder.
–MAOIs. Used in panic attacks.
–Antihistaminic agents. Present in over the
counter medications.
–Antipsychotics (Ziprasidone).
•Novel drugs. (Most of these are still on clinical trials).
–CCK
B (e.g. CCK
4).
–EAA's/NMDA (e.g. HA966).

11. Sedative/Hypnotics
•A hypnotic should produce, as much as
possible, a state of sleep that resembles
normal sleep.

12. Properties of Sedative/Hypnotics in
Sleep
1) The latency of sleep onset is decreased
(time to fall asleep).
2) The duration of stage 2 NREM sleep is
increased.
3) The duration of REM sleep is decreased.
4) The duration of slow-wave sleep (when
somnambulism and nightmares occur) is
decreased.
Tolerance occurs after 1-2 weeks.

13. Sedative/Hypnotics
1)Benzodiazepines (BZDs):
Alprazolam, diazepam, oxazepam, triazolam
2)Barbiturates:
Pentobarbital, phenobarbital
3)Alcohols:
Ethanol, chloral hydrate, paraldehyde,
trichloroethanol,
4)Imidazopyridine Derivatives:
Zolpidem
5)Pyrazolopyrimidine
Zaleplon

14. Sedative/Hypnotics
6) Propanediol carbamates:
Meprobamate
7) Piperidinediones
Glutethimide
8)Azaspirodecanedione
Buspirone
9) -Blockers**
Propranolol
10) 2-AR partial agonist**
Clonidine

15. Sedative/Hypnotics
Others:
11) Antyipsychotics **
Ziprasidone
12)Antidepressants **
TCAs, SSRIs
13)Antihistaminic drugs **
Dephenhydramine

16. Sedative/Hypnotics
All of the anxiolytics/sedative/hypnotics
should be used only for symptomatic relief.
*************
All the drugs used alter the normal sleep
cycle and should be administered only for
days or weeks, never for months.
************
USE FOR
SHORT-TERM TREATMENT
ONLY!!

17. Sedative/Hypnotics
Relationship between
Older vs Newer Drugs
BarbituratesBenzodiazepines
GlutethimideZolpidem
Meprobamate Zaleplon
**All others differ in their effects and therapeutic
uses. They do not produce general anesthesia
and do not have abuse liability.

18. SEDATIVE/HYPNOTICS
ANXYOLITICS
BENZODIAZEPINES BARBITURATES
GABAergic SYSTEM

19. Sedative/Hypnotics
The benzodiazepines are the most
important sedative hypnotics.
Developed to avoid undesirable
effects of barbiturates (abuse
liability).

20. Benzodiazepines
•Diazepam
• Chlordiazepoxide
•Triazolam
•Lorazepam
•Alprazolam
•Clorazepate => nordiazepam
•Halazepam
•Clonazepam
•Oxazepam
•Prazepam

21. Barbiturates
•Phenobarbital
•Pentobarbital
•Amobarbital
•Mephobarbital
•Secobarbital
•Aprobarbital

22. NORMAL

ANXIETY
_________  _________________
SEDATION

HYPNOSIS

Confusion, Delirium, Ataxia

Surgical Anesthesia
 COMA

DEATH

23. Respiratory
Depression
Coma/
Anesthesia
Ataxia
Sedation
Anxiolytic
Anticonvulsant
DOSE
R
E
S
P
O
N
S
E
BARBS
BDZs
ETOH

24. Respiratory
Depression
Coma/
Anesthesia
Ataxia
Sedation
Anxiolytic
Anticonvulsant
DOSE
R
E
S
P
O
N
S
E
BARBS
BDZs

25. GABAergic SYNAPSE
GABA
glutamate
glucose
Cl
-
GAD

26. GABA-A Receptor
•Oligomeric
(glycoprote
in.
•Major player in
Inhibitory Synapses.
•It is a Cl
-
Channel.
•Binding of GABA
causes the channel to
open and Cl
-
to flow
into the cell with the
resultant membrane
hyperpolarization.
GABA AGONISTS
BDZs



BARBs



27. Mechanisms of Action
1) Enhance GABAergic Transmission
 frequency of openings of GABAergic
channels. Benzodiazepines
 opening time of GABAergic channels.
Barbiturates
 receptor affinity for GABA. BDZs and BARBS
2) Stimulation of 5-HT
1A receptors.
3) Inhibit 5-HT
2A, 5-HT
2C, and 5-HT
3 receptors.

28. Patch-Clamp Recording of Single
Channel GABA Evoked Currents
From Katzung et al., 1996

29. Benzodiazepines
PHARMACOLOGY
•BDZs potentiate GABAergic inhibition at all
levels of the neuraxis.
•BDZs cause more frequent openings of the
GABA-Cl
-
channel via membrane
hyperpolarization, and increased receptor
affinity for GABA.
•BDZs act on BZ
1 (
1 and 
2 subunit-containing)
and BZ
2 (
5 subunit-containing) receptors.
•May cause euphoria, impaired judgement, loss
of cell control and anterograde amnesic effects.

30. Pharmacokinetics of Benzodiazepines
Although BDZs are highly protein bound
(60-95%), few clinically significant
interactions.*
High lipid solubility  high rate of entry
into CNS  rapid onset.
*The only exception is chloral hydrate and warfarin

31. C
N
S
E
f
f
e
c
t
s
(
R
a
t
e
o
f
O
n
s
e
t
)
Lipid solubility

32. Pharmacokinetics of Benzodiazepines
Hepatic metabolism. Almost all BDZs
undergo microsomal oxidation (N-
dealkylation and aliphatic hydroxylation)
and conjugation (to glucoronides).
Rapid tissue redistribution  long acting 
long half lives and elimination half lives
(from 10 to > 100 hrs).
All BDZs cross the placenta  detectable
in breast milk  may exert depressant
effects on the CNS of the lactating infant.

33. Pharmacokinetics of Benzodiazepines
Many have active metabolites with half-
lives greater than the parent drug.
Prototype drug is diazepam (Valium), which
has active metabolites (desmethyl-
diazepam and oxazepam) and is long
acting (t½ = 20-80 hr).
Differing times of onset and elimination
half-lives (long half-life => daytime
sedation).

34. Biotransformation of Benzodiazepines
From Katzung, 1998

35. Biotransformation of
Benzodiazepines
•Keep in mind that with formation of active
metabolites, the kinetics of the parent drug
may not reflect the time course of the
pharmacological effect.
•Estazolam, oxazepam, and lorazepam,
which are directly metabolized to
glucoronides have the least residual
(drowsiness) effects.
•All of these drugs and their metabolites are
excreted in urine.

36. Properties of Benzodiazepines
•BDZs have a wide margin of safety if used
for short periods. Prolonged use may cause
dependence.
•BDZs have little effect on respiratory or
cardiovascular function compared to BARBS
and other sedative-hypnotics.
•BDZs depress the turnover rates of
norepinephrine (NE), dopamine (DA) and
serotonin (5-HT) in various brain nuclei.

37. Side Effects of Benzodiazepines
•Related primarily to the CNS depression
and include: drowsiness, excess sedation,
impaired coordination, nausea, vomiting,
confusion and memory loss. Tolerance
develops to most of these effects.
•Dependence with these drugs may
develop.
•Serious withdrawal syndrome can
include convulsions and death.

38. Sedative/Hypnotics
•They produce a pronounce, graded,
dose-dependent depression of the
central nervous system.

39. Toxicity/Overdose with
Benzodiazepines
•Drug overdose is treated with flumazenil (a BDZ
receptor antagonist, short half-life), but respiratory
function should be adequately supported and
carefully monitored.
•Seizures and cardiac arrhythmias may occur
following flumazenil administration when BDZ are
taken with TCAs.
•Flumazenil is not effective against BARBs
overdose.

40. Drug-Drug Interactions with BDZs
•BDZ's have additive effects with other CNS
depressants (narcotics), alcohol => have a
greatly reduced margin of safety.
•BDZs reduce the effect of antiepileptic drugs.
•Combination of anxiolytic drugs should be
avoided.
•Concurrent use with ODC antihistaminic and
anticholinergic drugs as well as the
consumption of alcohol should be avoided.
•SSRI’s and oral contraceptives decrease
metabolism of BDZs.

41. Pharmacokinetics of Barbiturates
•Rapid absorption following oral
administration.
•Rapid onset of central effects.
•Extensively metabolized in liver (except
phenobarbital), however, there are no
active metabolites.
•Phenobarbital is excreted unchanged.
Its excretion can be increased by
alkalinization of the urine.

42. Pharmacokinetics of Barbiturates
•In the elderly and in those with limited
hepatic function, dosages should be
reduced.
•Phenobarbital and meprobamate cause
autometabolism by induction of liver
enzymes.

43. Properties of Barbiturates
Mechanism of Action.
•They increase the duration of GABA-gated
channel openings.
•At high concentrations may be GABA-
mimetic.
Less selective than BDZs, they also:
•Depress actions of excitatory
neurotransmitters.
•Exert nonsynaptic membrane effects.

44. Toxicity/Overdose
•Strong physiological dependence may
develop upon long-term use.
•Depression of the medullary respiratory
centers is the usual cause of death of
sedative/hypnotic overdose. Also loss of
brainstem vasomotor control and
myocardial depression.

45. Toxicity/Overdose
•Withdrawal is characterized by increase
anxiety, insomnia, CNS excitability and
convulsions.
•Drugs with long-half lives have mildest
withdrawal (.
•Drugs with quick onset of action are most
abused.
•No medication against overdose with
BARBs.
•Contraindicated in patients with porphyria.

46. Sedative/Hypnotics
Tolerance and excessive rebound occur in
response to barbiturate hypnotics.
NIGTHS OF DRUG DOSING
S
L
E
E
P

P
E
R

N
I
G
H
T
(
%
)
CONTROL WITHDRAWAL
NREM III and IV
REM
1 2 3

47. Miscellaneous Drugs
•Buspirone
•Chloral hydrate
•Hydroxyzine
•Meprobamate (Similar to BARBS)
•Zolpidem (BZ
1 selective)
•Zaleplon (BZ
1 selective)

48. BUSPIRONE
•Most selective anxiolytic currently available.
•The anxiolytic effect of this drug takes several
weeks to develop => used for GAD.
•Buspirone does not have sedative effects and
does not potentiate CNS depressants.
•Has a relatively high margin of safety, few side
effects and does not appear to be associated
with drug dependence.
•No rebound anxiety or signs of withdrawal
when discontinued.

49. BUSPIRONE
Side effects:
•Tachycardia, palpitations,
nervousness, GI distress and
paresthesias may occur.
•Causes a dose-dependent pupillary
constriction.

50. BUSPIRONE
Mechanism of Action:
•Acts as a partial agonist at the 5-HT
1A
receptor presynaptically inhibiting
serotonin release.
•The metabolite 1-PP has 
2 -AR
blocking action.

51. Pharmacokinetics of BUSPIRONE
•Not effective in panic disorders.
•Rapidly absorbed orally.
•Undergoes extensive hepatic metabolism
(hydroxylation and dealkylation) to form
several active metabolites (e.g. 1-(2-
pyrimidyl-piperazine, 1-PP)
•Well tolerated by elderly, but may have slow
clearance.
•Analogs: Ipsapirone, gepirone, tandospirone.

52. Zolpidem
•Structurally unrelated but as effective as
BDZs.
•Minimal muscle relaxing and anticonvulsant
effect.
•Rapidly metabolized by liver enzymes into
inactive metabolites.
•Dosage should be reduced in patients with
hepatic dysfunction, the elderly and patients
taking cimetidine.

53. Properties of Zolpidem
Mechanism of Action:
•Binds selectively to BZ
1 receptors.
•Facilitates GABA-mediated neuronal
inhibition.
•Actions are antagonized by flumazenil

54. ?
NE
DA
5-HT
ACh
(-)
(-)
(-)
(-)
(-)
ANXIOLYTIC ?
SEDATION ?
ANTICONVULSANT/
MUSCLE RELAXANT ?
GABA

55. Properties of Other drugs.
•Chloral hydrate
•Is used in institutionalized patients. It
displaces warfarin (anti-coagulant) from
plasma proteins.
•Extensive biotransformation.

56. Properties of Other Drugs
2-Adrenoreceptor Agonists (eg. Clonidine)
•Antihypertensive.
•Has been used for the treatment of panic
attacks.
•Has been useful in suppressing anxiety
during the management of withdrawal from
nicotine and opioid analgesics.
•Withdrawal from clonidine, after protracted
use, may lead to a life-threatening
hypertensive crisis.

57. Properties of Other Drugs
-Adrenoreceptor Antagonists
(eg. Propranolol)
•Use to treat some forms of anxiety,
particularly when physical (autonomic)
symptoms (sweating, tremor, tachycardia)
are severe.
•Adverse effects of propranolol may
include: lethargy, vivid dreams,
hallucinations.

58. OTHER USES
1. Generalized Anxiety Disorder
Diazepam, lorazepam, alprazolam, buspirone
2. Phobic Anxiety
a. Simple phobia. BDZs
b. Social phobia. BDZs
3. Panic Disorders
TCAs and MAOIs, alprazolam
4. Obsessive-Compulsive Behavior
Clomipramine (TCA), SSRI’s
5. Posttraumatic Stress Disorder (?)
Antidepressants, buspirone

59. ANXYOLITICS
Alprazolam
Chlordiazepoxide
Buspirone
Diazepam
Lorazepam
Oxazepam
Triazolam
Phenobarbital
Halazepam
Prazepam
HYPNOTICS
Chloral hydrate
Estazolam
Flurazepam
Pentobarbital
Lorazepam
Quazepam
Triazolam
Secobarbital
Temazepam
Zolpidem

60. References:
•Katzung, B.G. (2001) Basic and Clinical
Pharmacology. 7
th
ed. Appleton and Lange.
Stamford, CT.
•Brody, T.M., Larner,J., and Minneman, K.P. (1998)
Human Pharmacology: Molecular to Clinical. 2
nd
ed.
Mosby-Year Book Inc. St. Louis, Missouri.
•Rang, H.P. et al. (1995) Pharmacology . Churchill
Livingston. NY., N.Y.
•Harman, J.G. et al. (1996) Goodman and Gilman's
The Pharmacological Basis of Therapeutics. 9
th
ed.
McGraw Hill.