Antianxiety drugs ILOs By the end of this lecture you will be

able to Define different types of anxiety

disorders Classify types of drugs used for

treatment of anxiety Recognize the different characteristics of

antianxiety drugs

What is anxiety?

Physical and emotional distress which interfere with normal life.

“I always thought I was just a worrier. I’d feel keyed up and unable to relax. At times it would come and go, and at times it would be constant. It could go on for days. I’d worry about what I was going to fix for a dinner party, or what would be a great present for somebody. I just

couldn’t let something go”.

“I’d have terrible sleeping problems. There were times I’d wake up wired in the middle of the night. I had trouble concentrating, even reading

the newspaper or a novel .

Sometimes I’d feel a little lightheaded. My heart would race or pound. And that would make me worry more. I was always imagining things were worse than they really were. When I got a

stomachache, I’d think it was an ulcer”.

“I was worried all the time about everything. It didn't matter that there were no signs of problems, I just got upset. I was having trouble falling asleep at night, and I couldn't keep my mind focused at work. I felt angry at my family

all the time”.

Emotional Symptoms of anxiety irrational and excessive fear and worry Irritability Restlessness Trouble concentrating Feeling tensePhysical Symptoms of AnxietySweatingTachycardiaStomach upsetFrequent urination or diarrhea Sleep disturbances (Insomnia)Fatigue

Types of anxiety disorders

1- Generalized anxiety disorder

2- Panic disorder

3- Phobia

4-Post traumatic stress disorder 5- Obsessive compulsive disorder

Treatment of anxiety Psychotherapy

Anxiolytics

Classification of anxiolytic drugs:

1. Benzodiazepines ( BDZ ).

2. 5HT1A agonists.

3. 5HT reuptake inhibitors.

4. Tricyclic Antidepressants

5. MAO inhibitors

6. Beta-adrenergic blockers

Benzodiazepines

Mechanism of Action

Benzodiazepines act

by binding to BZ

receptors in the brain enhance GABA action

in the brain

PHARMACOKINETICS

Are lipid soluble Well absorbed orally, Can be given parenterally Chlordiazepoxide- Diazepam (IV only NOT IM) Widely distributed. Cross placental barrier (Fetal depression). Excreted in milk (neonatal depression).

Can be classified according to the duration of action into short, medium & long- acting

Pharmacological Actions

Anxiolytic action.

Pharmacological Actions

Depression of cognitive and psychomotor function Sedative & hypnotic actions Anterograde amnesiaMinimal depressant effects on

Cardiovascular system Respiratory system

Some have anticonvulsant effect: Clonazepam, diazepam.

Therapeutic Uses

Anxiety disorders:   Short term relief of severe anxietyGeneral anxiety disorderObsessive compulsive disorderPanic attack with depression Alprazolam

(antidepressant effect)

Sleep disorders (Insomnia). Triazolam, Lorazepam, Flurazepam

Therapeutic Uses

Treatment of epilepsy

Diazepam – Lorazepam

In anesthesia Preanesthetic medication (diazepam). Induction of anesthesia (Midazolam, IV)

Adverse Effects

• Ataxia (motor incoordination)• Cognitive impairment.• Hangover: (drowsiness, confusion) • Tolerance & dependence• Risk of withdrawal symptomsRebound insomnia, anorexia, anxiety, agitation, tremors and convulsion.

Use of benzodiaze

pine

Reduced anxiety

Effect wears

off

Even more

anxious

Adverse Effects

Toxic effects: respiratory & cardiovascular depression in large doses.

Drug interactions

Examples

CNS depressants Alcohol & Antihistaminics of effect of benzodiazepines

Cytochrome P450 (CYT P450) inhibitors

Cimetidine & Erythromycin

t ½ of benzodiazepines

CYT P450 inducers Phenytoin & Rifampicin

t 1/2 of benzodiazepines

Dose should be reduced in

o Liver diseaseo Old people.

Precaution Should not be used in pregnant women or breast-feeding. People over 65.

Quiz?

Which one of the following is most likely to result from treatment with moderate doses of diazepam?

(A) Alleviation of the symptoms of major depressive disorder

(B) Agitation and possible hyperreflexia

with abrupt discontinuance after chronic use

(C) Improved performance on tests of psychomotor function

(D) Retrograde amnesia

5HT1A agonistsBuspirone

Acts as agonist at brain 5HT1A receptors Rapidly absorbed orally. T½ : (2 – 4 h). Liver dysfunction its clearance.

BuspironeOnly anxiolytic No hypnotic effect. Not muscle relaxant. Not anticonvulsant. No potentiation of other CNS depressants. Minimal psychomotor and cognitive dysfunctions. Does not affect driving skills. Minimal risk of dependence. No withdrawal signs.

Uses of buspirone

As anxiolytic in mild anxiety & generalized anxiety disorders.

Disadvantages of buspirone

Slow onset of action (delayed effect) Not effective in severe anxiety/panic disorder. GIT upset, dizziness, drowsiness Drug Interactions with CYT P450 inducers and inhibitors

Quiz?

Which of the following statements about buspirone is correct:

A. It binds to 5HT receptors in the central nervous system

B. It has marked sedative activity C. It is chemically related to

benzodiazepines D. It causes marked central nervous

system depression when combined with alcohol

E. It possesses muscle relaxant activity

Beta Blockers

Propranolol – atenolol

Act by blocking peripheral sympathetic system. Reduce somatic symptoms of anxiety. Decrease BP & slow HR. Used in performance anxiety. Are less effective for other forms of anxiety

Tricyclic Antidepressants

Doxepin- imipramine – desipramine Act by reducing uptake of 5HT & NA. Used for anxiety especially associated with depression. Effective for panic attacks. Delayed onset of action (weeks).

Side effects of tricyclic antidepressants

Atropine like actions (dry mouth-blurred vision). α-blocking activity (Postural hypotension). Sexual dysfunction. Weight gain.

Selective serotonin reuptake inhibitors (SSRIs)

Fluoxetine acts by blocking uptake of 5HT Orally Delayed onset of action (weeks). Long half life Used for panic disorder – OCD - Generalized anxiety disorders - phobia.

Side effects of SSRIs

Nausea, diarrhea Sexual dysfunction Dry mouth Seizures Sleep disturbance

Monoamine oxidase inhibitors (MAOIs)

Phenelzine act by blocking the action of MAO enzymes. Used for panic attacks and phobia. Require dietary restriction Avoid wine, beer, fermented foods as old cheese

that contain tyramine.Side effectsDry mouth, constipation, diarrhea, restlessness, dizziness.

Synopsis of anxiolytics

CLASSES OF ANXIOLYTICS

USES

Benzodiazepines Generalized anxiety disorders, OCD, phobia, panic attack

SSRIs

(Fluoxetine)

Generalized anxiety disorders, OCD, phobia, panic attack

Tricyclic antidepressants

(doxepin, imipramine )

anxiety with depression.

panic attacks

5HT1A agonists

(Buspirone)

Mild anxiety

Not effective in panic attack

Beta blockers

(propranolol, atenolol)

Phobia (social Phobia)

Synopsis of anxiolyticsCLASSES OF

ANXIOLYTICSAdverse effects

Benzodiazepines Ataxia, confusion, dependence, tolerance, withdrawal symptoms,

SSRIs

(Fluoxetine)

weight gain, sexual dysfunction Dry mouth

Tricyclic antidepressants

(doxepin, imipramine )

weight gain, sexual dysfunction, atropine like actions

5HT1A agonists

(Buspirone)

Minimal adverse effects

Beta blockers

(propranolol, atenolol)

Hypotension

The wife of a 24-year-old computer programmer considers him to be of a "nervous disposition. " He is easily startled, worries about inconsequential matters, and sometimes complains of stomach cramps. At night he grinds his teeth in his sleep. There is no current history of drug abuse.

Q1

Assuming that the symptoms experienced by this young man are not related to a medical condition, the most appropriate drug treatment would be the judicious use of

(A) Buspirone

(B) Midazolam

(C) Triazolam (D) Phenelzine

Q2 Regarding the characteristic properties of the

drug prescribed for this young man, the physician should inform the patient to anticipate

(A) Additive CNS depression with alcoholic beverages

(B) A significant effect on memory

(C) That the drug will take a week or so to begin working

(D) A need to gradually increase drug dosage because of tolerance

(E) That if he stops taking the drug abruptly he will experience withdrawal signs