Antidepressants & Antimanic Drugs
Antidepressant drugs are primarily used to treat depressive disorders and anxiety disorders, but can also be effective for a range of other conditions. They work by altering the balance of neurotransmitters in the brain to improve mood, reduce anxiety, and alleviate other related symptoms. Antimanic drugs like lithium are also used to manage mania in bipolar disorder.
Classification
- Tricyclic Antidepressants (TCAs): Amitriptyline, Nortriptyline, Imipramine, Clomipramine
- Selective Serotonin Reuptake Inhibitors (SSRIs): Fluoxetine, Sertraline, Paroxetine
- Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs): Venlafaxine, Duloxetine, Desvenlafaxine
- Monoamine Oxidase Inhibitors (MAOIs): Phenelzine, Tranylcypromine, Isocarboxazid
- Lithium (for Antimanic effects)
Pharmacodynamics
- Tricyclic Antidepressants (TCAs):
- Inhibit the reuptake of serotonin and norepinephrine into the presynaptic neuron, increasing their levels in the synaptic cleft.
- Block histamine and muscarinic receptors, contributing to side effects like sedation and dry mouth.
- SSRIs:
- Inhibit the reuptake of serotonin into the presynaptic neuron, leading to increased serotonin levels and enhancing serotonergic neurotransmission.
- SNRIs:
- Inhibit the reuptake of both serotonin and norepinephrine, increasing both neurotransmitter levels in the synaptic cleft.
- MAOIs:
- Inhibit the monoamine oxidase enzyme, which breaks down serotonin, norepinephrine, and dopamine, leading to increased levels of these neurotransmitters in the brain.
- Lithium (for Antimanic Effects):
- Modulates neurotransmitter activity, stabilizes neuronal membranes, and affects intracellular signaling pathways to help prevent manic and depressive episodes.