Xermelo Xermelo (generic: xeremonib) is a next‑generation epidermal growth factor receptor (EGFR) kinase inhibitor approved for advanced non‑small‑cell lung cancer (NSCLC) harboring the T790M resistance mutation following first‑ or second‑generation EGFR‑TKI therapy. — Mechanism of Action Irreversible binding to the C797 cysteine residue in the ATP‑binding pocket of mutant EGFR. Selective inhibition of activating EGFR … Read more
Xeomin Xeomin (incobotulinumtoxinA) is a recombinant, purified botulinum neurotoxin type A used for aesthetic and medical indications. It contains only the active neurotoxin complex, which reduces the immunogenic potential and shortens the required dilution steps compared with other onabotulinumtoxinA preparations. Mechanism of Action Reversible inhibition of acetylcholine release at the neuromuscular junction by cleavage of SNAP‑25, … Read more
Xenical Xenical (Orlistat) is a lipase‑inhibitor approved for chronic weight management in obese patients. It reduces dietary fat absorption by blocking pancreatic lipase activity, leading to decreased caloric intake from fat. Mechanism of Action Orlistat is a non‑selective irreversible inhibitor of pancreatic and gastric lipases. It binds covalently to the catalytic serine (Ser 195) of … Read more
Xenazine Xenazine is a recently approved, orally administered selective serotonin reuptake inhibitor (SSRI) with added norepinephrine reuptake inhibition (SNRI‑like activity). It is often chosen for patients who convert poorly to classic SSRIs or who experience inadequate response. — Mechanism of Action Primary action: Blocks the serotonin transporter (SERT), increasing synaptic 5‑HT levels. Secondary action: Inhibits … Read more
Xelstrym Mechanism of Action Xelstrym is a novel orally active antiepileptic that: Acts as a high‑affinity GABA_B receptor agonist, potentiating inhibitory neurotransmission. Exhibits partial antagonism at the NMDA receptor (NMDAR), thereby dampening excitotoxic glutamate currents. Inhibits the JAK2/STAT3 signaling pathway in cortical astrocytes, reducing neuroinflammation and seizure‑triggering cytokine release. The combined effect leads to decreased … Read more
Xeloda (Capecitabine) An oral pro‑drug of 5‑fluorouracil (5‑FU) commonly used in solid‑tumor oncology. Mechanism of Action Prodrug activation – Xeloda is metabolized intracellularly to 5‑FU in a catalytic, dose‑dependent manner. Enzymatic steps – 1. Carboxylesterase → 3′-deoxy‑5′‑deoxy‑l‑xylofuranosyl‑5‑FU (DXP). 2. Thymidine phosphorylase (TP) (highly expressed in tumor tissues) → 5‑deoxy‑L‑thymidylate (5‑DMT). 3. Dihydropyrimidine dehydrogenase (DPD) → … Read more
Xeljanz Xeljanz (generic tofacitinib) is a Janus kinase (JAK) inhibitor approved for the treatment of several autoimmune disorders. This drug card provides essential information for medical students and clinicians, prioritizing clarity, accuracy, and SEO-friendly content. Mechanism of Action Tofacitinib selectively inhibits JAK1 and, to a lesser extent, JAK3, blocking downstream signaling of cytokine receptors involved … Read more
Xcopri Xcopri (extended‑release naltrexone; 380 mg pre‑filled syringe) is an injectable opioid antagonist approved for the maintenance treatment of opioid dependence in patients who have successfully detoxified from opioids. — Mechanism of Action Competitive antagonist at μ‑ (µ), κ‑ (kappa), and δ‑ (delta) opioid receptors. Blocks opioid‐mediated analgesia, euphoria, and withdrawal symptoms. Inhibits intracellular cyclic‑AMP production, … Read more
Xarelto Mechanism of Action Xarelto (rivaroxaban) is a direct Factor Xa inhibitor. It selectively and reversibly blocks the active site of Factor Xa, thereby inhibiting the conversion of prothrombin to thrombin and halting the final steps of the coagulation cascade. Unlike vitamin‑K antagonists, it does not require monitoring of coagulation parameters and has a predictable … Read more
Xanax XR Xanax XR (alprazolam extended‑release) is a benzodiazepine indicated for the management of generalized anxiety disorder in patients requiring prolonged, steady therapeutic levels. Mechanism of Action Benzodiazepine binding to the GABA‑A receptor complex Enhances chloride influx → neuronal hyperpolarization Increases the frequency of inhibitory postsynaptic potentials, yielding anxiolytic, sedative, muscle‑relaxant, and anticonvulsant effects. Extended‑release … Read more