25,729 articles
Ranitidine
Ranitidine (Zantac) is an H2 receptor antagonist for GERD, peptic ulcers, and Zollinger-Ellison syndrome. Withdrawn in 2020 over NDMA impurity formation during storage; FDA approved a reformulated version in November 2025.
Ranolazine
Ranolazine (Ranexa), an antianginal drug approved in the US (2006) and EU (2008) for chronic/stable angina; inhibits the late sodium current, reducing calcium overload without changing heart rate or blood pressure; null outcome trials, QT prolongation, CYP3A interactions.
Ranosidenib
Ranosidenib (HMPL-306) is HUTCHMED's oral dual inhibitor of mutant IDH1 and IDH2, blocking 2-hydroxyglutarate production. In Phase I R/R IDH-mutant AML it gave CR+CRh about 35% and is now in the China Phase III RAPHAEL trial versus salvage chemotherapy.
Ranpirnase
Ranpirnase, also known as Onconase or P-30 protein, is a cytotoxic ribonuclease isolated from northern leopard frog eggs and tested as a drug for mesothelioma, later repurposed as an antiviral.
Ranula
Ranula: a mucous extravasation pseudocyst of the sublingual gland in the floor of the mouth, from Latin rana (frog). Oral and plunging types; tail sign on imaging; sublingual gland excision gives lowest recurrence.
Rapacuronium
Rapacuronium (ORG 9487, Raplon) was an aminosteroidal nondepolarizing neuromuscular blocking agent approved in the US in 1999 for rapid intubation and withdrawn in 2001 after fatal bronchospasm linked to M2 muscarinic receptor antagonism.
RAPADILINO syndrome
RAPADILINO syndrome is a rare autosomal recessive disorder named for its main features: radial ray defects, absent kneecaps, cleft palate, diarrhea, short stature, and a long slender nose.
Rapastinel
Rapastinel (GLYX-13), a tetrapeptide NMDA receptor positive allosteric modulator developed by Allergan as a rapid antidepressant for major depressive disorder; positive phase 2 results and FDA breakthrough designation, but phase 3 failure and discontinued development.
Rape trauma syndrome
Rape trauma syndrome (RTS), described by Burgess and Holmstrom in 1974, is a cluster of post-rape reactions in acute and reorganization phases; not a DSM-5 diagnosis, contested scientifically and in court.
Raphael Katzen
Raphael "Ray" Katzen (1915–2009) was an American chemical engineer who founded the ethanol-plant consultancy Raphael Katzen Associates, now KATZEN International, and was elected to the National Academy of Engineering in 1996.
Rapid autopsy
Rapid autopsy, also known as rapid research autopsy or a warm autopsy, is a research procedure that collects tissue within hours of death, mostly to sample metastatic cancer comprehensively.
Rapid cycling
Rapid cycling, a course specifier of bipolar I and II disorder (ICD-11 6A80.5), means at least four manic, hypomanic, or depressive mood episodes within 12 months, associated with poorer treatment response.
Rapid diagnostic test
A rapid diagnostic test, or RDT, for malaria is a point-of-care immunochromatographic strip that detects Plasmodium antigens in finger-prick blood, giving results in about 15 to 30 minutes.
Rapid Diagnostic Tests
Rapid diagnostic tests (RDTs), also called rapid or point-of-care tests, are easy-to-use tests giving results in about 20-30 minutes from blood, urine, saliva, or nasal samples; used for COVID-19, malaria, HIV, strep, and pregnancy.
Rapid eye movement sleep
Rapid eye movement (REM) sleep, also called paradoxical sleep, is a sleep state with activated EEG, rapid eye movements, and muscle atonia, discovered by Aserinsky and Kleitman in 1953, generated by a pontine flip-flop switch, and linked to vivid dreaming and REM behavior disorder.
Rapid eye movement sleep behavior disorder
REM sleep behaviour disorder (RBD, REM sleep behavior disorder) is a parasomnia with loss of REM atonia and dream enactment; about 80% of isolated cases convert to synucleinopathy within 10 years; treated with clonazepam, melatonin, pramipexole, or rivastigmine.
Rapid plasma reagin
Rapid plasma reagin (RPR), also called RPR card test, is a macroscopic nontreponemal flocculation blood test that screens for syphilis and monitors antibody titers, using charcoal-containing cardiolipin antigen read with the naked eye.
Rapid sequence induction
Rapid sequence induction (RSI), also called rapid sequence intubation, is an anesthetic technique for urgent intubation of aspiration-risk patients, placing the breathing tube before any assisted ventilation.
Rapid-onset childhood obesity-hypothalamic dysfunction-hypoventilation-autonomic dysregulation syndrome
ROHHAD (rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation) is an ultra-rare pediatric syndrome, under 200 cases, first described 1965, named 2007, no known gene, PHOX2B-negative, mortality 50-60 percent.
Rapid-onset dystonia-parkinsonism
Rapid-onset dystonia-parkinsonism (RDP, DYT12, DYT/PARK-ATP1A3) is a very rare autosomal dominant movement disorder from ATP1A3 mutations, causing abrupt stress-triggered dystonia and parkinsonism with onset ages 4-55.
Rapidly involuting congenital hemangioma
Rapidly involuting congenital hemangioma (RICH, ORPHA:141184) is a rare benign vascular tumor fully formed in utero that shrinks rapidly after birth, usually within 6-14 months; GLUT1 negative, unlike infantile hemangioma.
RAPIDO trial
RAPIDO trial (NCT01558921), a phase 3 study of short-course radiotherapy plus preoperative CAPOX/FOLFOX before surgery versus chemoradiotherapy in high-risk locally advanced rectal cancer; reduced 3-year disease-related treatment failure (23.7% vs 30.4%) and doubled pCR, with no overall survival difference.
RaPPID trial
RaPPID trial (NCT03719170), a VA cluster-randomized pragmatic trial evaluating a national proton pump inhibitor de-prescribing program across 17 Veterans Integrated Service Networks, 9 intervention versus 8 control, with 12-month PPI prescribing as the primary outcome.
Rapunzel syndrome
Rapunzel syndrome: a rare trichobezoar (hairball) extending from the stomach through the pylorus into the small intestine, caused by trichotillomania and trichophagia, first described by Vaughan et al. in 1968, with fewer than 100 reported cases, mostly in adolescent females.
Rare disease
Rare disease: condition affecting few people; defined as under 1/2,000 prevalence in Europe, under 200,000 US patients, under 1/10,000 in Japan and China; over 7,000 diseases, 300 million people, treated via incentivized orphan drugs.
RAS-associated autoimmune leukoproliferative disease
RAS-associated autoimmune leukoproliferative disease (RALD, ALPS type IV) is a rare nonmalignant blood disorder caused by somatic KRAS or NRAS gain-of-function mutations, causing monocytosis, splenomegaly, and autoimmune cytopenias, distinguished from JMML by its indolent course.
Rasa Parpati
Rasa Parpati (Rasa Parpaṭī) is an Ayurvedic mercury-sulphur medicine of the Parpati ('flake') class in Rasashastra, made by pouring molten Kajjali on banana leaves; used mainly for Grahani and gastrointestinal disorders, with an Ayurvedic Formulary of India monograph.
RASA1-related capillary malformation-arteriovenous malformation
RASA1-related capillary malformation-arteriovenous malformation (CM-AVM1, OMIM 608354) is a rare autosomal dominant RASopathy causing multiple pink capillary malformations with a pale halo, with AVMs or AVFs in about a quarter of carriers.
Rasagiline
Rasagiline (Azilect) is a selective, irreversible MAO-B inhibitor drug approved for Parkinson's disease, first approved in Israel and Europe in 2005 and by the US FDA in 2006.
Rasahrdayatantra
Rasahṛdayatantra (रसहृदयतन्त्र), the Heart of Mercury, is a 10th-century Sanskrit alchemical text by Govinda, the earliest known rasaśāstra work: 506 verses, 19 chapters, eighteen mercury saṃskāras, and an elixir regimen.