Antidepressants Drugs Pharmacology Cheat Sheet

Antidepressants Drugs are primarily used for the treatment of depression. Depression can be a chronic or recurrent mental disorder presenting with symptoms such as depressed mood, loss of interest or pleasure, guilt feelings, disturbed sleep appetite, low energy, and difficulty in thinking. Depression can also lead to suicide.

Antidepressant Drugs

Antidepressants include the following groups:

• Tricyclics,
• Monoamine oxidase inhibitors (MAOIs),
• Selective serotonin reuptake inhibitors (SSRIs), serotonin-
• Norepinephrine reuptake inhibitors (SNRIs),
• Other antidepressants.

Depression may be due to reduced functioning of monoamine neurotransmitters (e.g., norepinephrine, serotonin [5-HT], dopamine) in the CNS (decreased amount and/or decreased effects at the receptor sites). Antidepressants block metabolism, increase amount/effects of monoamine neurotransmitters, and act at receptor sites (change responsiveness/ sensitivities of both presynaptic and postsynaptic receptor sites).


Developed to treat depression with fewer adverse effects, SSRIs are chemically different from TCAs and MAO inhibitors. Some of the SSRIs currently available are:
• Citalopram
• Escitalopram
• Fluoxetine
• Fluvoxamine
• Paroxetine
• Sertraline.

Adverse reactions:

Anxiety, insomnia, somnolence, and palpitations may occur with the use of an SSRI. Sexual dysfunction (anorgasmia and delayed ejaculation) and various skin rashes have been reported. Decreased glucose concentrations in plasma can occur with fluoxetine. Orthostatic hypotension may occur with citalopram and paroxetine use.

MAO inhibitors

MAO inhibitors are divided into two classifications based on their chemical structure:
• Hydrazines, which include phenelzine
• Nonhydrazines, consisting of a single drug, tranylcypromine.

Adverse reactions

Administering MAO inhibitors in small, divided doses may relieve some of the following adverse reactions:
• Hypertensive crisis (when taken with tyramine-rich foods)
• Orthostatic hypotension
• Restlessness, drowsiness, dizziness, and insomnia
• Headache
• Constipation, anorexia, and nausea and vomiting
• Weakness and joint pain
• Dry mouth
• Blurred vision
• Peripheral edema
• Urine retention and transient impotence
• Rash
• Skin and mucous membrane hemorrhage


TCAs are used to treat depression. They include:
• Amitriptyline hydrochloride
• Amoxapine
• Clomipramine
• Desipramine
• Doxepin
• Imipramine hydrochloride
• Imipramine pamoate
• Nortriptyline
• Protriptyline
• Trimipramine.

Adverse reactions

Adverse reactions to TCAs include:
• Orthostatic hypotension
• Sedation
• Jaundice
• Rashes and photosensitivity reactions
• Resting tremor
• Decreased sexual desire and inhibited ejaculation
• Transient eosinophilia
• Reduced white blood cell (WBC) count
• Manic episodes (in patients with or without bipolar disorder)
• Exacerbation of psychotic symptoms in susceptible patients.

Miscellaneous antidepressants

Other antidepressants in use today include:
• Maprotiline and mirtazapine, tetracyclic antidepressants
• Bupropion, a dopamine reuptake–blocking drug
• Venlafaxine and duloxetine, serotonin-norepinephrine reuptake inhibitors
• Trazodone, a triazolopyridine drug
• Nefazodone, a phenylpiperazine drug.


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