INTRODUCTION TO
PSYCHOPHARMACOLOGY
CHARLES P. SAMENOW, MD, MPH
OBJECTIVES
• Identify major classes of somatic treatments for the
major DSM-IV-TR Diagnoses
• Describe basic mechanism of action of somatic
treatments
• Explain how mechanism of action related to major
side effect profiles
ANTIDEPRESSANTS
TRICYCLIC ANTIDEPRESSANTS
• Block the re-uptake of three neurotransmitter
systems:
• Serotonin
• Norepinephrine
• Dopamine
• Utilized in:
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Major Depressive Disorder
Dysthymia
Generalized Anxiety Disorder
Panic Disorder
Obsessive-Compulsive Disorder
TRICYCLIC ANTIDEPESSANTS
• Older “Dirtier” Medication:
• 3-4 weeks for onset (sometimes even 4-6 weeks)
• Can be lethal in overdose (cardiotoxic)
• Have side effect profiles:
• Anticholinergic: dry mouth, constipation, confusion, urinary
retention
• Histaminic blockade: sedation and weight gain
• Alpha-adrengergic blockade: orthostatic hypotention
• Serotinergic: sexual side effect
MAOI
• Block Monoamine Oxidase in the wall of the gut,
CNS and platelets leading to build up of Dopamine
and Norepinephrine
• Utilized in:
• Major Depressive Disorder
• Atypical Depression
• Anxiety Disorders
MAOI
• Inhibition of MAO in the gut leads to increased
Tyramine absorption. Hence, patients must avoid
Tyramine containing foods (fava beans, aged
meats and cheeses, wines, sauerkraut, etc…)
• Ingestion of Tyramine can lead to hypertensive crisis
• Require 3-4 weeks (sometimes 6-8 weeks)
• Fatal in overdose
• Cannot be combined with other serotinergic acting
drugs (Tricyclic’s, SSRI’s) due to risk of serotonin
syndrome.
• Overdose can be fatal
SSRI
• Blockade of serotonin reuptake from the synapse
• Utilized in:
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Major Depression
Dysthymia
OCD
Panic Disorder
PTSD
Social Phobia
Bulimia Nervosa
Depressed phase of Bipolar (only with a mood stabilizer)
SSRI
• Take 2-4 weeks for onset
• Fewer side effects than older medications –
“Cleaner” and more easily tolerated
• First line agents in pregnancy (although Class C)
• Major side effects:
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Gastrointestinal (first few days)
Sexual Side Effects
Black Box Warning: Increased Suicidality in Adolescents
Treatment emergent mania in bipolar disorder
Discontinuation Syndrome
SNRI
• Blocks Re-uptake of Serotonin and Norepinephrine
• Careful balance between two neurotransmitter
systems
• Utilized in Depression, Anxiety and Pain Syndromes
• “Cleaner”/More Easily Tolerated
• Major Side Effects:
• Blood Pressure
• Discontinuation Syndrome
MISCELLANEOUS
• Wellbutrin (Buproprion)
Inhibition of Norepinephrine Re-uptake
No sexual side effects
Also marketed as Zyban for smoking cessation
Contraindicated in eating disorders due to lowering seizure
threshold
• Main side effect is anxiety
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• Remeron (Mirtazapine)
• Alpha-2 Antagonist (net effect -> increased norepinephrine)
• May cause sedation or increased weight gain
• Often used in the elderly
SEDATIVES/ANXIOLYTICS
BENZODIAZAPINES
• Use is determined by ½ life:
• Long (Diazepam, Chlorediazepoxide)
• Medium (Alprazolam)
• Short (Lorazepam)
• Utilized for panic and insomnia
• Potentiation of GABA receptors by binding to
special binding site
• Long-term use may lead to tolerance, withdrawal
and physiologic dependence
• Side effects are sedation and amnesia
OTHERS
• Beta-Blockers –
• Utilized for performance anxiety
• Centrally acting/lipophilic  propranolol
ANTIPSYCHOTICS
TYPICAL ANTIPSYCHOTICS
• High Potency (Haldol)
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Primary action is blocking D2 receptors (antagonist)
High affinity for D2 = lower dose
Good control of positive symptoms
Major Side Effects:
• EPS -dystonic reactions, prolactin, akasthesia, parkinsonism
• Neuroleptic Malignant Syndrome –
• Mid/Low Potency (Thorazine)
• Lower affinity for D2 = higher dose
• Less EPS
• More anticholinergic, alpha-adreinergic, and histiminic side
effects
DOPAMINE HYPOTHESIS OF
SCHIZOPHRENIA
Mesocortical pathway
Hypoactivity:
negative, cognitive,
and mood symptoms
Tuberoinfundibular pathway
(inhibits prolactin release [D2])
Nigrostriatal pathway
(part of EP system)
Mesolimbic pathway
Hyperactivity:
positive symptoms
(hallucinations,
delusions)
Clinical profile: Dopamine (D2)
blockade
Mesolimbic D2
EFFICACY: (+) SSX
MesocorticalD2
INEFFICACY: (-) SSX,
cognition, mood
Nigrostriatal D2
SIDE EFFECTS: EPS
D2
Tuberoinfundibular
SIDE EFFECTS: HPL
SCHIZOPHRENIA (TREATMENT)
HIGH
Fluphenazine (D)
Trifluoperazine
Thiothixine
Haloperidol (D)
MEDIUM
Perphenazine
Prochlorperazine
Loxapine
Acetophenazine
Triflupromazine
Chlorprothixine
Mesoridazine
LOW
Thioridazine
Chlorpromazine
EPS, HPL
EPS, HPL
Anti-H1: Sedation, wt gain
Anti-H1
Anti-α-1: Orthostasis, reflex tachycardia
Anti-α-1
Anti-M1: Blurry vision, dry mouth,
constipation, urinary retention, tachycardia,
memory problems or delirium in susceptible
patients
Anti-M1
Seizure, arrythmias, retinitis,
skin discoloration, photosens
EPS
• Dystonia – acute, involuntary muscle spasms often seen
in ocular muscles and neck
• Parkinsonism – tremor, cogwheel rigidity, masked facies,
and shuffling gait
• Akasthesia – a subjective sense of restlessness.
• Tardive Dyskinesia – long-term involuntary jerking of face,
neck, trunk or extremities. May be permanent.
http://www.youtube.com/watch?v=R0EbgpyztCA
ATYPICAL (SECOND GENERATION)
• Utilized in:
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Acute Schizophrenia
Maintenance of Schizophrenia
Acute Mania
Maintenance of Bipolar
Treatment of Bipolar Depression
• Mechanism of Action: Blockade of D2 and 5HT-2A.
Serotonin modulate dopamine, particularly in the
nigrostriatal pathways. Hence, more Dopamine
blockade in the mesolimbic as opposed to
nigrostriatal pathways.
A.
5HT
B.
DA
C.
5HT
DA
release
D.
DA
+/-
DA
release
ATYPICALS
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Often first line
Efficacy on positive and negative symptoms
NMS and EPS unlikely
Side Effects are based on receptor profile
Prolongation of QTc (Cardiovascular)
Metabolic Syndrome
• Weight Gain
• Glucose Intolerance
• Increased Lipids and Triglycerides
MOOD STABILIZERS
LITHIUM
• Indicated for acute mania and maintenance
bipolar
• Specific evidence to support use in preventing
suicide
• Blocks inositol-1-phosphatase
• Narrow therapeutic range: dangerous in overdose
• Side Effects:
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Tremor
Renal Impairment
Thyroid Dysfunction
Cardiovascular
ANTICONVULSANTS
• Major Agents: Carbamazepine, Valproic Acid and
Lamotrigene
• May prevent kindling
• Each agent has side effects that are outside scope
of this lecture
SUMMARY
Disorder
Treatment
Depression
SSRI, SNRI, Buproprion, Mirtazepine
Atypical Depression
MAOI
Anxiety Disorders
Short-Term: Benzodiazepine
Long-Term: SSRI, SNRI
OCD
High Dose SSRI, Tricyclics
PTSD
SSRI
Performance Anxiety
Beta-Blocker
Psychosis
Atypical Antipsychotic
Acute Mania
Atypical Antipsychotic, Lithium,
Carbamazepine
Bipolar Maintenance
Atypical Antipsychotics, Lithium
Carbamazepine
Bipolar Depression
Lamotrigine, Some Atypicals
Rapid Cyclling/Mixed Episodes
Valproic Acid