Introduction Sodium nitroprusside is a potent intravenous vasodilator used mainly in hypertensive emergencies and acute heart failure. It rapidly reduces both preload and afterload through release of nitric oxide (NO), causing relaxation of vascular smooth muscle. Because of its rapid onset and short duration, it is commonly used in intensive care settings with continuous blood … Read more
Introduction Sodium bicarbonate is a systemic alkalinizing agent used in metabolic acidosis, cardiac arrest, hyperkalemia, urinary alkalinization, and certain drug toxicities. It acts by increasing plasma bicarbonate concentration, buffering excess hydrogen ions, and raising blood pH. Sodium bicarbonate also alkalinizes urine and can enhance elimination of certain toxins. Mechanism of Action (Step-wise) A key exam … Read more
Introduction Serotonin-norepinephrine reuptake inhibitors (SNRIs) are antidepressant drugs used in major depressive disorder, anxiety disorders, neuropathic pain, fibromyalgia, and other conditions. They enhance serotonergic and noradrenergic neurotransmission by inhibiting reuptake of serotonin and norepinephrine in the central nervous system. Common SNRIs include venlafaxine, desvenlafaxine, duloxetine, and levomilnacipran. Mechanism of Action (Step-wise) A key exam point … Read more
Introduction Sirolimus, also known as rapamycin, is an immunosuppressant drug primarily used in organ transplantation and certain proliferative disorders. It inhibits T-cell activation and proliferation by blocking the mammalian target of rapamycin (mTOR) pathway. Unlike calcineurin inhibitors, sirolimus does not inhibit interleukin-2 production but instead blocks the cellular response to interleukin-2. Mechanism of Action (Step-wise) … Read more
Introduction Simvastatin is a statin medication used to lower cholesterol levels and reduce the risk of cardiovascular disease. It acts by inhibiting hepatic cholesterol synthesis, leading to increased removal of low-density lipoprotein (LDL) cholesterol from the bloodstream. Simvastatin is widely used in hypercholesterolemia, atherosclerosis prevention, and cardiovascular risk reduction. Mechanism of Action (Step-wise) A key … Read more
Introduction Sertraline is a selective serotonin reuptake inhibitor (SSRI) commonly used in depression, anxiety disorders, obsessive-compulsive disorder (OCD), panic disorder, post-traumatic stress disorder (PTSD), and related psychiatric conditions. It enhances serotonergic neurotransmission in the brain by selectively inhibiting serotonin reuptake at presynaptic neurons. Mechanism of Action (Step-wise) A key exam point is that sertraline selectively … Read more
Introduction Seroquel is the brand name for quetiapine, an atypical antipsychotic medication used in schizophrenia, bipolar disorder, and major depressive disorder. It acts on multiple neurotransmitter receptors in the central nervous system, particularly dopamine and serotonin receptors. Its balanced serotonin-dopamine antagonism helps reduce psychotic symptoms while lowering the risk of extrapyramidal side effects compared with … Read more
Introduction Senna is a stimulant laxative derived from the leaves and pods of Senna species plants. It is commonly used for short-term treatment of constipation and bowel evacuation before diagnostic procedures. Senna acts mainly in the colon by stimulating intestinal motility and increasing water secretion into the bowel lumen. Mechanism of Action (Step-wise) A key … Read more
Introduction Selegiline is a selective monoamine oxidase-B (MAO-B) inhibitor primarily used in Parkinson disease. It increases dopamine availability in the central nervous system by inhibiting dopamine metabolism. At higher doses, selectivity for MAO-B decreases and inhibition of MAO-A may also occur. Selegiline helps improve motor symptoms and may reduce fluctuations in Parkinson disease. Mechanism of … Read more
Introduction Scopolamine is an antimuscarinic drug primarily used for prevention of motion sickness and postoperative nausea and vomiting. It acts by blocking muscarinic acetylcholine receptors in the central and peripheral nervous systems. Scopolamine has significant effects on the vestibular system and vomiting center, making it especially useful in motion-related nausea. Mechanism of Action (Step-wise) A … Read more
