Psychopharmacology

By: Saleha Qamer

Ph.D Scholar
(Lecture 11)
19/02/2024
Dopamine Antagonist
• A dopamine antagonist (antidopaminergic) is a type
of drug which blocks dopamine receptors by
receptor antagonism.

• Most antipsychotics are dopamine antagonists, and as

such they have found use in treating schizophrenia,
bipolar disorder, and stimulant psychosis.

• Several other dopamine antagonists are antimetics used

in the treatment of nausea and vomiting.
Dopamine antagonists include:
 Domiperidone (Motilium, Stemetil
 Olanzapine (Zyprexa)
 Haloperidol (Haldol)
 Chlorpromazine (Thorazine)
Serotonin Antagonist
• A serotonin antagonist is a drug used to inhibit the
action at serotonin (5-HT) receptors.

• Antagonists of the (5-HT) receptor are sometimes used

as atypical antipsychotics (contrast with typical
antipsychotics, which are purely dopamine antagonists.
They include:

 Clozapine (clozaril)
 Risperidone (risperidal)
Adrenergic Antagonist
• An adrenergic antagonist is a pharmaceutical substance
that acts to inhibit the action of catecholamine at the
adrenergic receptors.

• It is thus a type of sympatholytic (drugs that inhibit nerve

impulses in the sympathetic nervous system).

• Many important and commonly prescribed medications

are adrenergic antagonists, including prazosin (T.N
Minipress, vasoflex) and propanolol (Inderal,
Tenormin).
GABA Receptor Antagonist
• GABA receptor antagonists are drugs that inhibit the
action of GABA.

• In general these drugs produce stimulant and convulsant

effects, and are mainly used for counteracting overdoses
of sedative drugs.

• Drugs with possible antagonistic effects include

thiothixene (Navane - antipsychotic), bupropion
(Wellbutrin – antidepressant / smoking cessation aid)
and caffeine.
 Mental Health Medications

• There are three general terms, used interchangeably,

that describe drugs that treat psychiatric disorders—

1. psychotropic drugs
2.psychoactive drugs, and
3.Psychotherapeutic drugs.
• Traditionally, these agents have been divided into the
following four categories:

(1)antipsychotic drugs or neuroleptics used to treat

psychosis,
(2)antidepressant drugs used to treat depression,
(3)Anti-manic drugs or mood stabilizers used to treat
bipolar disorder, and
(4)Anti-anxiety drugs or anxiolytics used to treat anxious
states (which are also effective as hypnotics in high
dosages).
• Such categoric distinctions, however, have become less valid for the
following reasons:

1. Many drugs of one class are used to treat disorders previously

assigned to another class. For example, most antidepressant drugs
are now also used to treat a broad range of anxiety disorders.

2. Drugs introduced as treatments for schizophrenia, agents such as

the serotonin–dopamine antagonists (SDAs), are also indicated for
the management of bipolar disorder and appear to have some
antidepressant activity.

3. Drugs from all four categories are used to treat symptoms and
disorders such as insomnia, eating disorders, behavioral
disturbances associated with dementia, and impulse-control
disorders.
4. Drugs such as clonidine (Catapres), propranolol (Inderal), and
gabapentin (Neurontin) can effectively treat a variety of psychiatric
disorders and do not fit easily into the traditional classification of
drugs.

5. Some descriptive psychopharmacologic terms are arbitrary and

overlap in meaning. For example, anxiolytics decrease anxiety,
sedatives produce a calming or relaxing effect, and hypnotics
produce sleep. However, most anxiolytics function as sedatives and
at high doses can be used as hypnotics, and all hypnotics at low
doses can be used for daytime sedation.
How are medications used to treat mental
disorders?
• Medications treat the symptoms of mental disorders.

• They cannot cure the disorder, but they make people feel better so
they can function

• Medications work differently for different people. Some people get

great results from medications and only need them for a short time.
For example, a person with depression may feel much better after
taking a medication for a few months, and may never need it again.

• People with disorders like schizophrenia or bipolar disorder, or

people who have long-term or severe depression or anxiety may
need to take medication for a much longer time
• Some people get side effects from medications and other people
don’t.
• Doses can be small or large, depending on the medication and the
person.

Factors that can affect how medications work in people

include:
• Type of mental disorder, such as depression, anxiety, bipolar
disorder, and schizophrenia
• Age, sex, and body size
• Physical illnesses
• Habits like smoking and drinking
• Liver and kidney function
• Genetics
• Other medications and herbal/vitamin supplements
• Diet
• Whether medications are taken as prescribed
 Medications to treat Schizophrenia

• Antipsychotic medications are used to treat schizophrenia.

• Some of these medications have been available since the mid-1950’s
They are also called conventional “typical” antipsychotics.

• Some of the more commonly used medications include:

• Chlorpromazine (Thorazine)
• Haloperidol (Haldol)
• Perphenazine (generic only)
• Fluphenazine (generic only)
• In the 1990’s, new antipsychotic medications were developed.

• These new medications are called second generation, or “atypical”

antipsychotics.

• One of these medications was clozapine (Clozaril). It is a very

effective medication that treats psychotic symptoms, hallucinations,
and breaks with reality, such as when a person believes he or she is
the president. But clozapine can sometimes cause a serious problem
called agranulocytosis, which is a loss of the white blood cells
that help a person fight infection.

• Therefore, people who take clozapine must get their white blood cell
counts checked every week or two. This problem and the cost of
blood tests make treatment with clozapine difficult for many people.
Still, clozapine is potentially helpful for people who do not respond
to other antipsychotic medications.
• Other atypical antipsychotics were developed. All of them are
effective, and none cause agranulocytosis These include:
• Risperidone (Risperdal)
• Olanzapine (Zyprexa)
• Aripiprazole (Abilify)
 Medications to treat Depression

• Depression is commonly treated with antidepressant medications.

• Antidepressants work to balance some of the natural chemicals in
our brains. These chemicals are called neurotransmitters, and they
affect our mood and emotional responses.
• Antidepressants work on neurotransmitters such as serotonin,
norepinephrine, and dopamine.

• The most popular types of antidepressants are called selective

serotonin reuptake inhibitors (SSRIs) These include:
• Fluoxetine (Prozac)
• Citalopram (Celexa)
• Sertraline (Zoloft)
• Paroxetine (Paxil)
• Escitalopram (Lexapro)
• Other types of antidepressants are serotonin and norepinephrine
reuptake inhibitors (SNRIs).

• SNRIs are similar to SSRIs and include venlafaxine (Effexor) and

duloxetine (Cymbalta).

• Another antidepressant that is commonly used is bupropion

(Wellbutrin) which works on the neurotransmitter dopamine.

• SSRIs and SNRIs are popular because they do not cause as many
side effects as older classes of antidepressants.

• Older antidepressant medications include tricyclics, tetracyclics,

and monoamine oxidase inhibitors (MAOIs). For some people,
tricyclics, tetracyclics, or MAOIs may be the best medications.
 Medications to treat Bipolar Disorder

• Bipolar disorder, also called manic-depressive illness, is commonly

treated with mood stabilizers Sometimes, antipsychotics and
antidepressants are used along with a mood stabilizer.

Mood stabilizers
• People with bipolar disorder usually try mood stabilizers first.
Lithium is a very effective mood stabilizer. It was the first mood
stabilizer approved by the FDA in the 1970’s for treating both manic
and depressive episodes.

• Anticonvulsant medications also are used as mood stabilizers They

were originally developed to treat seizures, but they were found to
help control moods as well.
• One anticonvulsant commonly used as a mood stabilizer is valproic
acid, also called divalproex sodium (Depakote).

• Other anticonvulsants used as mood stabilizers are carbamazepine

(Tegretol), lamotrigine (Lamictal) and oxcarbazepine (Trileptal)
Atypical antipsychotics
• Atypical antipsychotic medications are sometimes used to treat
symptoms of bipolar disorder.

• Antipsychotics used to treat people with bipolar disorder include:

• Olanzapine (Zyprexa), which helps people with severe or psychotic

depression, which often is accompanied by a break with reality,
hallucinations, or delusions
• Aripiprazole (Abilify), which can be taken as a pill or as a shot
• Risperidone (Risperdal)
• Clozapine (Clorazil), which is often used for people who do not
respond to lithium or anticonvulsants
Antidepressants
• Antidepressants are sometimes used to treat symptoms of
depression in bipolar disorder.

• Fluoxetine (Prozac), paroxetine (Paxil), or sertraline (Zoloft) are a

few that are used.

• However, people with bipolar disorder should not take an

antidepressant on its own Doing so can cause the person to rapidly
switch from depression to mania, which can be dangerous. To
prevent this problem, doctors give patients a mood stabilizer or an
antipsychotic along with an antidepressant
 Medications to treat Anxiety Disorders

• Antidepressants, anti-anxiety medications, and beta-blockers are

the most common medications used for anxiety disorders

Anxiety disorders include:

• Obsessive compulsive disorder (OCD)
• Post-traumatic stress disorder (PTSD)
• Generalized anxiety disorder (GAD)
• Panic disorder
• Social phobia
Antidepressants
• Antidepressants were developed to treat depression, but they also
help people with anxiety disorders.

• SSRIs such as fluoxetine (Prozac), sertraline (Zoloft), escitalopram

(Lexapro), paroxetine (Paxil), and citalopram (Celexa) are
commonly prescribed for panic disorder, OCD, PTSD, and social
phobia.

• The SNRI venlafaxine (Effexor) is commonly used to treat GAD.

• The antidepressant bupropion (Wellbutrin) is also sometimes used

when treating anxiety disorders, antidepressants generally are
started at low doses and increased over time.
• Some tricyclic antidepressants work well for anxiety. For example,
imipramine (Tofranil) is prescribed for panic disorder and GAD.

• Clomipramine (Anafranil) is used to treat OCD.

• Tricyclics are also started at low doses and increased over time

• MAOIs are also used for anxiety disorders. Doctors sometimes

prescribe phenelzine (Nardil), tranylcypromine (Parnate), and
isocarboxazid (Marplan)
Benzodiazepines (anti-anxiety medications)
• The anti-anxiety medications called benzodiazepines can start
working more quickly than antidepressants. The ones used to treat
anxiety disorders include:

• Clonazepam (Klonopin), which is used for social phobia and GAD

• Lorazepam (Ativan), which is used for panic disorder
• Alprazolam (Xanax), which is used for panic disorder and GAD
• Buspirone (Buspar) is an anti-anxiety medication used to treat GAD
Unlike benzodiazepines, however, it takes at least two weeks for
buspirone to begin working
Beta-blockers
• Beta-blockers control some of the physical symptoms of anxiety,
such as trembling and sweating.

• Propranolol (Inderal) is a beta-blocker usually used to treat heart

conditions and high blood pressure

• The medicine also helps people who have physical problems related
to anxiety. For example, when a person with social phobia must face
a stressful situation, such as giving a speech, or attending an
important meeting, a doctor may prescribe a beta-blocker
 Medications to treat ADHD

• Attention deficit/hyperactivity disorder (ADHD) occurs in both

children and adults. ADHD is commonly treated with stimulants,
such as:

• Methylphenidate (Ritalin, Metadate, Concerta, Daytrana)

• Amphetamine (Adderall)
• Dextroamphetamine (Dexedrine, Dextrostat)
• Atomoxetine (Strattera)
• Lisdexamfetamine dimesylate (Vyvanse)