Introduction Rosuvastatin is a statin medication used to treat hypercholesterolemia and reduce cardiovascular risk. It lowers low-density lipoprotein (LDL) cholesterol by inhibiting hepatic cholesterol synthesis. Rosuvastatin is one of the most potent HMG-CoA reductase inhibitors and is widely used in prevention of atherosclerotic cardiovascular disease. Mechanism of Action (Step-wise) A key exam point is that … Read more
Introduction Rivastigmine is a centrally acting cholinesterase inhibitor used primarily in Alzheimer disease and Parkinson disease-associated dementia. It improves cognitive function by increasing acetylcholine levels in the brain. Rivastigmine inhibits both acetylcholinesterase and butyrylcholinesterase enzymes, enhancing cholinergic neurotransmission in cortical and hippocampal regions involved in memory and cognition. Mechanism of Action (Step-wise) A key exam … Read more
Introduction Ritalin is the brand name for methylphenidate, a central nervous system stimulant primarily used in attention-deficit/hyperactivity disorder (ADHD) and narcolepsy. It improves attention, concentration, and behavioral control by increasing dopamine and norepinephrine activity in the brain, especially in the prefrontal cortex. Mechanism of Action (Step-wise) A key exam point is that methylphenidate blocks dopamine … Read more
Introduction Risperidone is an atypical antipsychotic medication used in schizophrenia, bipolar disorder, irritability associated with autism spectrum disorder, and other psychiatric conditions. It works mainly through antagonism of dopamine and serotonin receptors in the central nervous system. Compared with typical antipsychotics, risperidone has lower extrapyramidal toxicity at therapeutic doses because of its combined serotonin-dopamine antagonistic … Read more
Introduction Rifaximin is a poorly absorbed rifamycin antibiotic primarily used for gastrointestinal infections and disorders. It acts locally within the gastrointestinal tract and is commonly prescribed for traveler’s diarrhea, hepatic encephalopathy, and irritable bowel syndrome with diarrhea (IBS-D). Rifaximin inhibits bacterial RNA synthesis, leading to suppression of intestinal bacterial growth. Mechanism of Action (Step-wise) A … Read more
Introduction Rifampicin, also known as rifampin, is a bactericidal antibiotic primarily used in the treatment of tuberculosis and other mycobacterial infections. It belongs to the rifamycin class and acts by inhibiting bacterial RNA synthesis. Rifampicin is an essential first-line antitubercular drug and is also used in prophylaxis against meningococcal and Haemophilus influenzae infections. Mechanism of … Read more
Introduction Ribavirin is a broad-spectrum antiviral drug used in combination therapy for chronic hepatitis C infection and in certain viral respiratory infections such as respiratory syncytial virus (RSV). It is a synthetic guanosine analog that interferes with viral RNA synthesis and replication through multiple mechanisms. Mechanism of Action (Step-wise) A key exam point is that … Read more
Introduction Repaglinide is an oral antidiabetic drug belonging to the meglitinide class. It is primarily used in type 2 diabetes mellitus to control postprandial blood glucose levels. Repaglinide stimulates rapid insulin secretion from pancreatic β-cells by closing ATP-sensitive potassium channels, thereby improving glucose control after meals. Mechanism of Action (Step-wise) A key exam point is … Read more
Introduction Rasburicase is a recombinant urate oxidase enzyme used for the prevention and treatment of hyperuricemia associated with tumor lysis syndrome (TLS). It rapidly lowers serum uric acid levels by converting uric acid into allantoin, a more water-soluble and easily excreted metabolite. Rasburicase is particularly useful in oncology patients with rapidly proliferating tumors undergoing chemotherapy. … Read more
Introduction Ranitidine is a histamine H2 receptor antagonist previously used in the treatment of peptic ulcer disease, gastroesophageal reflux disease (GERD), and acid-related disorders. It reduces gastric acid secretion by blocking histamine-mediated stimulation of gastric parietal cells. Although its use has declined in many countries due to concerns regarding NDMA contamination, its pharmacological mechanism remains … Read more
