Cardiovascular, metabolic, and endocrine drugs

Orforglipron

Orforglipron (Foundayo) is Eli Lilly's once-daily oral, non-peptide GLP-1 receptor agonist, discovered by Chugai and FDA-approved April 1, 2026 for weight management; doses up to 17.2 mg, no food or water restrictions, half-life 29-49 hours.

ORIGIN trial

ORIGIN trial (Outcome Reduction with an Initial Glargine Intervention), NCT00069784: 2x2 factorial RCT in 12,537 dysglycemic adults at high cardiovascular risk; insulin glargine and 1 g/day omega-3 both neutral for cardiovascular outcomes, cancer, and mortality over 6.2 years.

Orlistat

Orlistat (Xenical, alli; tetrahydrolipstatin) is a gastrointestinal lipase inhibitor weight-loss drug blocking about 30% of dietary fat absorption; 120 mg prescription and 60 mg OTC, with GI side effects and 2026 FDA kidney-injury warnings.

Ormeloxifene (centchroman)

Ormeloxifene (centchroman), sold in India as Saheli and Chhaya, is a non-steroidal SERM and once-weekly oral contraceptive developed by CSIR-CDRI, also used for abnormal uterine bleeding and mastalgia.

Orteronel

Orteronel (TAK-700, S-TAK-700) is Takeda's oral nonsteroidal selective CYP17A1 17,20-lyase inhibitor for prostate cancer; Phase III ELM-PC 4/5 and SWOG-1216 failed overall survival endpoints and development ended in 2014.

Osilodrostat

Osilodrostat (Isturisa, LCI699) is an oral cortisol synthesis inhibitor blocking CYP11B1 (and CYP11B2), FDA-approved in 2020 and expanded in 2025 for endogenous hypercortisolemia in adult Cushing's syndrome; dosing starts at 2 mg twice daily up to 30 mg twice daily.

Ospemifene

Ospemifene (Osphena, Senshio) is an oral SERM, 60 mg daily with food, for moderate to severe vulvar and vaginal atrophy, dryness, and dyspareunia in postmenopausal women; FDA-approved 2013, EU 2015.

Otamixaban

Otamixaban (FXV673, XRP0673) is an intravenous, reversible direct factor Xa inhibitor (Ki 0.5 nM) developed by Sanofi-Aventis for acute coronary syndrome; its phase 3 TAO trial showed no efficacy benefit and doubled bleeding, so it was never approved.

Otenabant

Otenabant (CP-945,598), Pfizer's selective CB1 cannabinoid receptor antagonist (Ki 0.7 nM), was trialed for obesity and NASH but its clinical program was terminated in 2008 after rimonabant's psychiatric safety withdrawal.

Ouabain

Ouabain (strophanthin-G), C29H44O12, is a cardiotonic cardiac glycoside from Strophanthus gratus and Acocanthera, an Na+/K+-ATPase inhibitor once used intravenously for heart failure, not US-approved, and the namesake of the proposed adrenal hormone endogenous ouabain.

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.

Ozagrel

Ozagrel (ozagrel sodium; brands Xanbon, Katalclot) is a thromboxane A2 synthase inhibitor antiplatelet drug approved in Japan for post-SAH vasospasm and acute cerebral thrombosis, used for ischemic stroke in Japan, China, and Korea.

Paltusotine

Paltusotine, sold as Palsonify, is a nonpeptide, orally given selective agonist of the somatostatin receptor subtype 2, approved in the United States in September 2025 to treat acromegaly in adults.

Papaverine

Papaverine, a benzylisoquinoline opium alkaloid discovered by Georg Merck in 1848, is a smooth-muscle relaxant and vasodilator (PDE inhibitor) used for vascular spasm and in intracavernosal injection mixtures for erectile dysfunction, without narcotic effects.

Paricalcitol

Paricalcitol (Zemplar) is a synthetic 19-nor vitamin D2 analog of calcitriol that binds the vitamin D receptor to suppress PTH, FDA-approved since 1998 for secondary hyperparathyroidism in CKD stages 3-5, adults and children 10+.

Parnaparin sodium

Parnaparin sodium (Fluxum) is a low-molecular-weight heparin from porcine intestinal mucosa, mean MW about 4.5–5 kDa, anti-Xa/anti-IIa ratio above 4, used for thromboprophylaxis, superficial vein thrombosis, and vascular disorders.

Pasireotide

Pasireotide (SOM230, Signifor) is a cyclic hexapeptide somatostatin analogue approved in 2012 for Cushing's disease, binding SSTR5 strongly; its main drawback is hyperglycemia from suppressed insulin and incretin secretion.

Patiromer calcium

Patiromer calcium (patiromer sorbitex calcium, Veltassa) is a non-absorbed oral potassium-binding polymer with a calcium-sorbitol counterion that treats chronic hyperkalemia by exchanging calcium for potassium in the colon, raising fecal potassium excretion; onset 7-48 hours, common effects constipation and hypomagnesemia.