Depression & Antidepressants

Flashcards about Depression and Antidepressants

What percentage of depression cases are classified as secondary depression?

60%

What are the three classifications of depression according to its origin?

Secondary depression, Endogenous depression (Major Depression), and Depression associated with Manic depressive disorder

What are the typical symptoms of depression?

Sadness, loss of libido, disturbance in appetite and sleep (usually decreased), suicidal tendencies, and psychotic symptoms

What are some atypical symptoms of depression?

Anxiety, phobias, obsessions, hypochondriasis, overeating, and increased sleep

What is the Mono-Amine theory of depression?

A decrease in the activity of norepinephrine and 5-HT neurotransmitters in the brain results in depression

What are the two major steps in the mechanism of action of antidepressants?

Elevation of brain biogenic amines and Down regulation of brain Beta and 5-HT2 receptors

According to the mechanism of action, what are the three classifications of Antidepressants?

Amine Pump Inhibitors, Mono-amine Oxidase Inhibitors (MAOI), and Presynaptic Alpha-2 blockers

What is the mechanism of action of Amine Pump Inhibitors?

They inhibit neuronal uptake of biogenic amines, allowing their accumulation at the synaptic cleft and potentiating their action at postsynaptic receptors.

What is the mechanism of action of Mono-amine Oxidase Inhibitors (MAOI)?

They inhibit the MAO enzyme, thus inhibiting the metabolism of biogenic amine stores available for release.

What is the mechanism of action of Presynaptic Alpha-2 blockers?

Blockade of these receptors results in increased release of biogenic amines into the synaptic cleft.

Into what two groups are Tricyclic Antidepressants (TCAs) classified?

Tertiary Amines and Secondary Amines

What are the autonomic side effects of TCAs?

Histamine H1 block leading to sedation and fatigue, interactions that potentiate antimuscarinic drugs, and Alpha-blockade leading to Postural hypotension and Tachycardia

What are some symptoms of TCA toxicity?

Atropine toxicity, Arrhythmias, Convulsions, Acidosis, and Coma

What are some examples of Heterocyclics?

Trazodone and Mianserine

What are some examples of Serotonin-selective reuptake blockers?

Fluoxetine

What are some disadvantages of Fluoxetine?

Nausea, Anxiety, insomnia, Sexual dysfunction, and Serotonin syndrome

What are some therapeutic uses of TCAs, Heterocyclics, and Serotonin-selective reuptake inhibitors?

Depression, Panic attacks and Phobic disorders, Chronic pain, Nocturnal enuresis, and Obsessive-compulsive disorder

What are the two forms of the MAO enzyme?

MAO-A and MAO-B

What is the primary function of the MAO-A enzyme?

Metabolism of Norepinephrine and 5-HT

What is the primary function of the MAO-B enzyme?

Selective metabolism of Dopamine

What are the three classifications of MAOIs?

Non-selective MAOIs, Selective MAO-A inhibitor, and Selective MAO-B inhibitor

Give some examples of Adverse effects of MAOIs

Insomnia, Mania and Convulsions in acute over dosage, Anticholinergic (less than T.C.A), and Postural hypotension (Ganglion blockade)

Give some examples of Serious food and drug interactions of MAOIs

MAOIs + Sympathomimetics in cold remedies produce Hypertensive crisis, MAOIs + TCA result in Hypertension + Hyperthermia + Convulsions, MAOIs + Serotonin-selective reuptake inhibitor produce Serotonin syndrome leading to Hyperthermia and Convulsions, MAOIs + Pethidine results in respiratory depression + Hyperthermia + Convulsions, and Cheese reaction

What should patients on MAOIs be warned against?

The serious drug interactions and should be given a list of foods they should avoid

When should patients on MAOIs receive TCA or Serotonin-selective reuptake inhibitors?

Not except after 2 weeks from cessation of MAOIs

Why is there less risk of cheese reactions with Moclobemide?

Selective MAO-A inhibitor, sparing MAO-B allowing it to metabolize Tyramine, and Short acting reversible inhibitor. It binds reversibly to MAO-A enzyme thus is easily displaced by Tyramine, allowing Tyramine to be metabolized by the MAO enzyme

What are some therapeutic uses of MAOIs?

Atypical depression, Panic attacks and Phobic disorders and Refractory cases of endogenous Depression with typical symptoms