25,729 articles
Off-Label Use
Off-label use: prescribing an approved medicine outside its marketing authorization (unapproved indication, dose, route, or patient group). Legal and common; 21% of US outpatient use, mostly lacking strong evidence.
OFF-MED trial
OFF-MED (NCT07320768), also called PRAISE-AF in its design paper, is a single-center randomized sham-controlled trial at Shanghai Chest Hospital testing renal denervation added to pulsed field ablation in 86 patients with persistent atrial fibrillation off antiarrhythmic drugs.
Off-pump coronary artery bypass
Off-pump coronary artery bypass (OPCAB, OPCABG) is beating-heart coronary bypass grafting without cardiopulmonary bypass, first performed by Goetz in 1960, revived in the 1980s, offering less stroke but more repeat revascularization than on-pump CABG.
Office hysteroscopy
Office hysteroscopy is an outpatient gynecological procedure in which a thin hysteroscope is inserted through the cervix to diagnose and treat intrauterine abnormalities in one visit.
Ofloxacin
Ofloxacin (Floxacin, formerly Floxin) is a second-generation fluoroquinolone antibiotic reported by Daiichi Pharmaceutical in 1982, inhibiting bacterial DNA gyrase and topoisomerase IV; used orally, otically, and ophthalmically, with a notably higher Achilles tendon complication risk than ciprofloxacin or levofloxacin.
Ofranergene obadenovec
Ofranergene obadenovec (ofra-vec, VB-111) is a non-replicating adenovirus 5 gene therapy from VBL Therapeutics targeting tumor blood vessels; its phase III OVAL ovarian cancer trial missed survival endpoints.
Ogden syndrome
Ogden syndrome (NAA10-related Ogden syndrome) is a rare X-linked recessive infantile-lethal disorder caused by the recurrent NAA10 Ser37Pro variant, impairing the NatA acetyltransferase complex, with growth delay, hypotonia, aged facies, and cardiac arrhythmia.
Ogilvie syndrome
Ogilvie syndrome, or acute colonic pseudo-obstruction, is massive colonic dilatation without mechanical obstruction, first described by Sir Heneage Ogilvie in 1948; treated with supportive care, neostigmine, or colonoscopy.
Oglemilast
Oglemilast (GRC 3886) is Glenmark's oral PDE4 inhibitor for asthma and COPD, out-licensed to Forest Labs ($190M deal) and Teijin Pharma ($53M), terminated after a failed Phase IIb COPD trial in 2009.
Oglufanide
Oglufanide (thymogen, IM-862) is the INN for the dipeptide L-glutamyl-L-tryptophan, a VEGF-inhibiting antiangiogenic and immunomodulatory agent; approved in Russia, it failed Western oncology trials including a 202-patient phase III in AIDS-Kaposi sarcoma.
Oguchi disease
Oguchi disease is a rare autosomal recessive retinal disorder causing congenital stationary night blindness and the Mizuo-Nakamura phenomenon, first described by Chuta Oguchi in Japan in 1907.
OHCS study
OHCS study (One Hospital ClinicalService Project, NCT01007474) is Medtronic Italia's observational medical care quality improvement registry of patients with Medtronic implantable cardiac devices, started January 2004 across 41 sites in 9 countries, with hospital data ownership and subprojects on pacemakers, ICDs, stroke, and heart failure.
Ohio Department of Health
Ohio Department of Health (ODH), Columbus-based cabinet-level state public health agency led by Director Bruce Vanderhoff since 2021; created 1917, successor to the 1886 State Board of Health; works with 111 local health departments and holds PHAB accreditation.
Okihiro syndrome
Okihiro syndrome, or Duane-radial ray syndrome (DRRS), is a rare autosomal dominant SALL4-related disorder combining Duane anomaly with radial ray malformations, hearing loss, and renal and cardiac defects.
Okur-Chung neurodevelopmental syndrome
Okur-Chung neurodevelopmental syndrome (OCNDS, OMIM 617062) is an ultra-rare autosomal dominant disorder caused by CSNK2A1 variants encoding CK2α, discovered in 2016 by Okur and Chung, causing developmental delay, hypotonia, language deficits, and sometimes seizures.
Olanzapine
Olanzapine (Zyprexa) is an atypical antipsychotic blocking D2 and 5-HT2A receptors, FDA-approved in 1996 for schizophrenia and in 2000 for bipolar mania; highly effective but strongly linked to weight gain and metabolic syndrome.
Old age
Old age: the later stage of human life, WHO threshold 60 years; not a disease in ICD-11, renamed 'Ageing associated decline in intrinsic capacity'; 1 billion people 60+ in 2019 rising to 2.1 billion by 2050.
Oldest people
Oldest people: verified record holders for human longevity. Jeanne Calment, 122 years 164 days, is the oldest validated person ever; João Marinho Neto and Ethel Caterham held living titles; GRG and LongeviQuest validate supercentenarian ages.
Oleclumab
Oleclumab (MEDI9447) is AstraZeneca/MedImmune's human anti-CD73 monoclonal antibody that blocks adenosine-mediated immunosuppression; tested with durvalumab in NSCLC (COAST, PACIFIC-9), pancreatic, colorectal, and breast cancer trials.
Olecranon
Olecranon: the proximal ulnar projection forming the bony tip of the elbow, triceps insertion site; prone to fracture (Mayo classification, ORIF or tension band wiring) and olecranon bursitis.
Olecranon bursitis
Olecranon bursitis, also called elbow bursitis or miner's elbow, is inflammation of the fluid-filled sac over the elbow tip, usually from repeated pressure; septic forms (20-33%) need antibiotics, most cases resolve conservatively in 3-6 weeks.
Olesoxime
Olesoxime (TRO19622), a cholesterol-oxime mitochondrial neuroprotectant from Trophos later owned by Roche, was trialed in SMA and ALS but showed no significant benefit and development ended in 2018.
Olezarsen
Olezarsen (Tryngolza), an Ionis GalNAc-conjugated antisense oligonucleotide targeting apoC-III mRNA, lowers triglycerides; FDA-approved 2024 for familial chylomicronemia syndrome and 2026 for severe hypertriglyceridemia.
Olfactory bulb
Olfactory bulb: first central processing station for smell in the forebrain, receiving olfactory nerve input in glomeruli (100-200 um) and relaying via mitral and tufted cells to piriform cortex; site of adult neurogenesis and a marker in neurodegenerative disease.
Olfactory nerve
The olfactory nerve, or CN I, is the first cranial nerve, carrying smell signals from the roof of the nasal cavity to the olfactory bulbs of the brain.
Olfactory receptor cell
Olfactory receptor cell, also called olfactory receptor neuron or olfactory sensory neuron: bipolar neuron in the nasal olfactory epithelium that detects odorants via GPCR-cAMP transduction in its cilia and sends unmyelinated axons to the olfactory bulb; each expresses one odorant receptor and turns over throughout life.
Olfactory reference disorder
Olfactory reference disorder (ORD, formerly olfactory reference syndrome, jikoshu-kyofu) is a psychiatric condition involving persistent false belief of emitting a foul body odor; ICD-11 code 6B22, treated with SRIs, antipsychotics, and CBT.
Olgotrelvir sodium capsules
Olgotrelvir sodium capsules (奥格特韦钠胶囊, Aoweining), also known as STI-1558 or OVYDSO, are a dual Mpro and cathepsin L inhibitor oral antiviral for mild-to-moderate COVID-19, NMPA-approved in China in October 2025 without ritonavir.
Oliceridine
Oliceridine (Olinvyk, TRV130) is an intravenous mu-opioid receptor agonist approved by the FDA in 2020 for moderate to severe acute pain in adults; developed by Trevena as a G protein-biased agonist, with contested mechanism and roughly half morphine's adverse-event odds at equal analgesia.
Oligo-ovulation
Oligo-ovulation (oligoovulation), infrequent ovulation defined as cycles over 35 days or fewer than 8 per year; ICD-11 5A80.4; a Rotterdam-criteria feature of PCOS with a milder phenotype than anovulation.