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Ovulation test
An ovulation test is a urine-based diagnostic test that detects the luteinizing hormone surge predicting ovulation within 24 to 36 hours, used for fertility timing since the mid-1970s.
OVULATION trial
OVULATION (NCT05695352), also called the IG-002 trial, is InnovaGyn's Phase II study testing oral levonorgestrel 1.5 mg plus meloxicam 15 mg against placebo for delaying ovulation by at least 7 days in normal menstruating women aged 18 to 40.
OWBLM trial
OWBLM (NCT04425681) is a phase II single-arm trial of osimertinib 80 mg daily plus bevacizumab 7.5 mg/kg for leptomeningeal metastasis from EGFR-mutant NSCLC; 14 patients, median LM PFS 9.3 months, ORR 50%, LM OS 12.6 months.
Oxacillin
Oxacillin is a semisynthetic, penicillinase-resistant penicillin of the isoxazolyl series, once sold as Prostaphlin, used to treat penicillinase-producing staphylococcal infections and used in testing for methicillin resistance (MRSA).
Oxaliplatin
Oxaliplatin, sold as Eloxatin, is a platinum-based chemotherapy drug approved in the United States in 2002 for colorectal cancer, used with 5-fluorouracil and leucovorin; its dose-limiting toxicity is peripheral neuropathy.
Oxandrolone
Oxandrolone (Oxandrin) is a synthetic 17-alpha-alkylated anabolic steroid, formerly FDA-approved for weight gain and corticosteroid catabolism; approval withdrawn June 2023. Best studied in burns: faster recovery, no mortality benefit, hepatotoxicity risk.
Oxaprozin
Oxaprozin (DAYPRO, COXANTO) is a long-half-life propionic acid NSAID inhibiting COX-1/COX-2, indicated for osteoarthritis, rheumatoid arthritis, and juvenile rheumatoid arthritis at 1,200 mg once daily, maximum 1,800 mg or 26 mg/kg daily.
Oxazepam
Oxazepam (Serax) is a short-acting benzodiazepine for anxiety, insomnia, and alcohol withdrawal, marketed since 1965. It is glucuronidated directly with no active metabolites, preferred in liver disease and the elderly, and a US Schedule IV drug.
Oxcarbazepine
Oxcarbazepine (Trileptal) is a carbamazepine-related dibenzazepine antiseizure prodrug converted to active MHD, a sodium-channel blocker used for focal seizures; notable for hyponatremia risk and few enzyme interactions.
Oxethazaine
Oxethazaine (oxetacaine, INN; Strocain, Mucaine) is a highly potent ethanolamine local anesthetic, C28H41N3O3, active at gastric acid pH and used orally in antacid combinations for gastritis, peptic ulcer, and heartburn pain.
Oxford knee score
The Oxford knee score is a 12-item patient questionnaire measuring pain and function in knee osteoarthritis, scored 0 to 48, introduced in 1998 and used in the NHS PROMs program.
Oxford–AstraZeneca COVID-19 vaccine
Oxford–AstraZeneca COVID-19 vaccine (ChAdOx1-S, AZD1222, Vaxzevria, COVISHIELD): replication-deficient chimpanzee adenoviral vector vaccine by Oxford's Jenner Institute and AstraZeneca; 63–72% efficacy, over 3 billion doses, ~6.2 million lives saved in 2021, withdrawn worldwide in 2024.
Oxiconazole
Oxiconazole (Oxistat) is a topical imidazole antifungal, US-approved 1988 as the first once-daily topical antifungal, for tinea pedis, cruris, corporis, and versicolor; 1% cream and lotion, negligible systemic absorption.
Oxidative balance score
The oxidative balance score (OBS) is a composite index combining about 20 pro-oxidant and antioxidant dietary and lifestyle exposures, developed as a practical alternative to oxidative stress biomarkers.
Oxiglutatione
Oxiglutatione (glutathione disulfide, GSSG, NOV-002, Glutoxim) is the oxidized form of glutathione, used in FDA-approved eye-surgery irrigating solutions BSS Plus (1981) and Navstel (2008) and investigated as an anticancer chemoprotective agent.
Oximetry
Oximetry, or pulse oximetry (SpO2), is the non-invasive optical measurement of blood oxygen saturation, invented by Takuo Aoyagi in 1972-1974; accuracy is under 2% bias at SaO2 ≥90% but reduced by dark skin pigmentation and poor perfusion.
Oxiracetam
Oxiracetam is a synthetic racetam-family nootropic drug tested in clinical trials for dementia, post-stroke cognitive impairment, and cognitive impairment after traumatic brain injury, with favorable safety but mixed results.
Oxoglutaric aciduria
Oxoglutaric aciduria, or alpha-ketoglutarate dehydrogenase deficiency (OMIM 203740), is a very rare autosomal recessive TCA cycle disorder caused by OGDH variants on 7p13, presenting neonatally with hypotonia, seizures, lactic acidemia, and elevated urinary alpha-ketoglutaric acid, distinct from 2-hydroxyglutaric acidurias and glutaric aciduria type I.
Oxolamine
Oxolamine (CAS 959-14-8), a non-narcotic 1,2,4-oxadiazole antitussive with mainly peripheral action, used for non-productive cough in Latin America, Turkey, and Taiwan; not US-approved.
Oxomemazine
Oxomemazine (oxomémazine), also known by brands like Toplexil, is a sedative phenothiazine H1 antihistamine (ATC R06AD08) used as an antitussive for dry cough in adults and children over 2, despite lacking RCT evidence of efficacy.
Oxybutynin
Oxybutynin (Ditropan, Oxytrol) is an antimuscarinic drug for overactive bladder, first US-approved 1975. Oral bioavailability is 6% with high N-DEO metabolite levels causing dry mouth; transdermal forms reach 80% bioavailability. Also used off-label for hyperhidrosis; flagged for cognitive risk in older adults.
Oxycodegol
Oxycodol (NKTR-181) is a mu-opioid agonist developed by Nektar Therapeutics. It is defined by its slow CNS entry and reduced abuse potential, but it failed regulatory review in 2020.
Oxycodone
Oxycodone: semisynthetic opioid analgesic synthesized from thebaine in Germany in 1916; metabolized mainly by CYP3A4/5 to noroxycodone and CYP2D6 to oxymorphone; extended-release OxyContin is the most commonly misused prescription opioid.
Oxygen bar
Oxygen bar, or recreational oxygen station: a wellness venue serving scented concentrated oxygen via nasal cannula. Began in Tokyo 1988; O2 Spa Bar Toronto 1996; health claims lack evidence.
Oxygen Consumption
Oxygen consumption (VO2) is the rate at which tissues or the whole body use oxygen, measured by indirect calorimetry; key units are mL O2/kg/min and METs (1 MET = 3.5 mL O2/kg/min), with VO2max as the main fitness metric.
Oxygen saturation (medicine)
Oxygen saturation (SaO2/SpO2) is the percentage of hemoglobin carrying oxygen, measured non-invasively by pulse oximetry, invented by Takuo Aoyagi in 1972; normal 95-100%, with known accuracy limits from skin pigmentation.
Oxygen therapy
Oxygen therapy: administration of supplemental medicinal oxygen, an WHO essential medicine, via cannulas, masks, or high-flow devices; landmark NOTT and MRC trials established survival benefit of long-term oxygen in severe COPD hypoxemia.
Oxygen toxicity
Oxygen toxicity: tissue damage from breathing oxygen above physiological partial pressures. Also Paul Bert effect (CNS seizures, 1.3–1.6 atm diving limit) and Lorrain Smith effect (lung damage above 0.5 ata prolonged exposure).
Oxygen–hemoglobin dissociation curve
Oxygen–hemoglobin dissociation curve (oxyhemoglobin dissociation curve, ODC): sigmoid plot of hemoglobin oxygen saturation versus oxygen partial pressure; P50 about 26 mmHg for adult blood, shifted right by low pH, high CO2, heat, and 2,3-DPG, left by fetal hemoglobin and carbon monoxide.
Oxygenators
Oxygenators, also called artificial lungs or membrane oxygenators, are blood-gas exchangers used in cardiopulmonary bypass and ECMO; modern designs use polypropylene hollow fiber membranes for oxygen and carbon dioxide exchange.