Home > Anatomy, Biology, Chemistry, pharmacology > Introduction to Human Anatomy Lecture 26 Notes: Antidepressants

Introduction to Human Anatomy Lecture 26 Notes: Antidepressants


Today is a brief 31 minute presentation on tricyclic antidepressants.


Affective Mood Disorders

Depression.  The inability to handle emotional feelings.  About 1 in 8 Americans have or will have an antidepressant medication.  Twice as common in women, more common in the elderly.

Types of Depression

1) Reactive

60% of all depression

This occurs in response to a loss.  Sadness, SAD, anxiety, tension, fatigue, will laugh at something funny

2) Endogenous/Neurochemical

25% of all depressions

chronic fatigue, does not find humor in anything, associated with family history, oversleeping.  Will have to be on medication for the rest of their life.

3) Mania

Impulsive, agitated

4) Manic Depressive/bipolar

10% of all depressions

mood swings, intensive irritability

Tricyclic Antidepressants (TCAs)

Prototype: imipramine

PD: blocks reuptake of serotonin and norepinephrine and dopamine, increase NT levels.  Increase sympathetic response.

PK: plasma half-life of 24 hours, takes 2 weeks to 2 months for an antidepressant to begin working.  Therapeutic index of 10-30 (low).

Clinical Uses: used to treat depression, treat chronic orofacial pain, treat bipolar disorder.

Adverse effects: weight gain, xerostomia (dry mouth), constipation, tachycardia, photophobia.  atropine like sides (parasympatholic).

Other Tricyclic Antidepressants


widely used, less atropine like actions




no atropine like actions, used in control of smoking.

Monoamine Oxidase Inhibitors

Prototype: phenelzine

PD: inhibits the action of MAO, increase seratonin, norepinephrine, dopamine

Clinical Uses: used when other ADs fail.

PK: slow onset

Adverse Effects: anxiety, insomnia, xerostomia, constipation, urinary retention.

Lithium Carbonate

PD: increases reuptake of norepinephrine.

Clinical Uses: effective in 80% of cases of manic states

PK: Excreted from kidneys, half life of 24 hours.

Antipsychotic Drugs

Schizophrenia – loss of reality.  There’s a spectrum of severity.  Lack of pleasure.


Prototype : amitriptyline

PD: block dopamine receptors in the limbic system, more effective at reducing positive symptoms than negative symptoms, slowing of psychomotor activity.

PK: given orally and IM.  Plasma half life of 30 hours.  Accumulates in fatty tissue.



D = eE

E = hf

Z = R + Xi

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