Tricyclic Antidepressants (TCAs), including Desipramine (Norpramin), Imipramine (Tofranil), Clomipramine (Anafranil), and Amitriptyline (Elavil), inhibit serotonin and norepinephrine reuptake and also block other receptors. They are used for depression, pain conditions, and insomnia. Common adverse effects include anticholinergic effects, sedation, orthostatic hypotension, and weight gain. They have a narrow therapeutic window and so require plasma-level monitoring. Abrupt discontinuation can...

Atypical antidepressants, including bupropion (Wellbutrin), mirtazapine (Remeron), nefazodone (Serzone), trazodone (Desyrel), and vilazodone (Viibryd), offer unique mechanisms of action. Bupropion weakly inhibits dopamine and norepinephrine reuptake, aiding depression treatment and smoking cessation, with a low risk of sexual dysfunction. Mirtazapine enhances serotonin and norepinephrine neurotransmission, leading to sedation, increased appetite, and weight gain. As a result, it helps treat...

Class III antiarrhythmic drugs are a group of medications that can prolong action potentials in the heart. They achieve this by blocking potassium channels or enhancing inward currents from sodium channels. However, these drugs have a unique property of "reverse use-dependence," which is most pronounced at slower heart rates and can lead to torsades de pointes—a specific type of arrhythmia. However, it is essential to note that excessive QT interval prolongation—a measure of the heart's...

Antidepressant drugs are a class of medications primarily used for treating various mood disorders, including major depression, anxiety disorders, and other related conditions. These medicines work by modulating the neurotransmitter balance within the brain, alleviating depressive symptoms. Antidepressants can be broadly categorized into several groups according to their mechanism of action and chemical structure: Selective Serotonin Reuptake Inhibitors (SSRIs), Serotonin-Norepinephrine...

Arrhythmia is a condition characterized by an irregular heart rhythm, with ECG changes that differ based on its origin and nature. The types of arrhythmias discussed below include atrial, junctional, and ventricular arrhythmias.Atrial ArrhythmiasPremature Atrial Complexes (PACs): PACs are early atrial beats caused by stress, caffeine, alcohol, electrolyte imbalances, hypoxia, hyperthyroidism, or certain medications (e.g., bronchodilators and decongestants). The ECG shows early P waves with an...

Certain drugs can affect how neurotransmitters called catecholamines, are released or taken back up in the adrenergic neuron. They can have different effects on the body's sympathetic transmission. Reserpine, a natural compound found in the Rauwolfia shrub, blocks a transporter called vesicular monoamine transporter (VMAT), which leads to a buildup of catecholamines in the cell and reduces sympathetic transmission. Another drug called guanethidine works in multiple ways, including blocking...