Antidepressants (Linger) Flashcards
SSRIs
drug list
Citalopram (Celexa) Escitalopram (Lexapro) Fluoxetine (Prozac) Fluvoxamine* Paroxetine (Paxil) Sertraline (Zoloft)
SNRIs
drug list
Duloxetine
Venlafaxine
have actions at > serotonin and norepinephrine transporters
Tetracyclics and Unicyclics
(atypical antidepressants) drug list
Bupropion
Mirtazapine (common for seniors due to depression and weight loss issues)
have potent action at NE transporters
5-HT Modulators
drug list
Trazodone - can cause priapism (erection)
TCAs drug list (tricyclic)
Amitriptyline
Desipramine
Imipramine
Nortriptyline
not first line anymore
MAOIs drug list
Selegiline
Biological Basis of Depression
Several hypotheses have been proposed
- Monoamine Hypothesis
- Receptor Hypothesis
- Neurotrophic Factor Hypothesis
- Neuroendocrine Factor Hypothesis
These hypotheses are not mutually exclusive
MDD is a complex disease likely to involve aspects of all these ideas
Mood is regulated by 3 systems
dopamine (attention, motivation, pleasure, reward)
norepinephrine (alertness, energy)
Serotonin (obsessions and compulsions)
Major Classes of Antidepressants
First-line agents:
- Selective Serotonin Reuptake Inhibitors (SSRIs)
- Serontonin-Norepinephrine Reuptake Inhibitors (SNRIs)
- (Some) Tetracyclics and Unicyclics (catch-all class)
Second- and third-line agents:
- Tricyclic Antidepressants (TCAs)
- Monoamine Oxidase Inhibitors (MAOIs)
Infrequently used agents:
- 5-HT2 Antagonists
Efficacy of Antidepressants
30-40% of patients achieve remission within a single trial of 8-12 weeks
70-80% of patients achieve remission by switching to another agent or augmentation by addition of another drug
* Antidepressant drugs are roughly equivalent in terms of efficacy
Antidepressants are more effective when combined with psychotherapy
Choosing an Antidepressant
The choice of an antidepressant depends first on the indication; not all indications are equally responsive to all antidepressants
In the treatment of MDD, safety and side effects are usually primary considerations in deciding which drug will be tried first in a depressed patient
Although antidepressant drugs are roughly equivalent in terms of efficacy, individual patients may fare better on one drug than on another for unknown reasons
Often finding the right drug for a patient must be done by trial and error
Selective Serotonin Reuptake Inhibitors (SSRIs)
Newest generation of antidepressants
Fewer side effects than older agents due to minimal affinity for muscarinic, adrenergic, and histamine receptors
Relatively safe in overdose unless combined with other drugs, including alcohol
Fluoxetine (Prozac®) Sertraline (Zoloft®) Paroxetine (Paxil®) Citalopram (Celexa®) Escitalopram (Lexapro®) Fluvoxamine* (Luvox®)
- Labeled only for obsessive-compulsive disorder
SSRIs: Mechanism of Action
Allosteric inhibition of the serotonin transporter (SERT)
Effectively increases the concentration of serotonin in the synaptic cleft
~80% of SERT activity is blocked at therapeutic doses
Downregulation of postsynaptic 5-HT2A receptor density has been proposed as an adaptive process provoked by chronic administration of SSRIs
SNRIs & TCAs: Mechanism of Action
Inhibit SERT and NET, the norepinephrine reuptake transporter
Effectively increases the concentration of both 5-HT and NE in the synaptic cleft
Most SNRIs tends to exhibit greater affinity for SERT than for NET
Different TCAs have different relative affinities for either NET or SERT
MAOIs: Mechanism of Action
MAOs are mitochondrial enzymes that metabolizes monoamines
MAOIs cause accumulation of NE, 5-HT, and/or DA in vesicular storage in nerve endings and enhances neurotransmitter concentrations in the synaptic cleft