Gastrointestinal and respiratory drugs

Decongestant

Decongestants, also called nasal decongestants, are vasoconstrictor medicines (pseudoephedrine, phenylephrine, oxymetazoline, xylometazoline) that relieve stuffy nose; topical use is limited to 5 days to avoid rebound congestion and rhinitis medicamentosa, and oral phenylephrine was found ineffective by FDA advisers.

Denufosol

Denufosol (denufosol tetrasodium, INS37217), an inhaled P2Y2 receptor agonist developed by Inspire Pharmaceuticals to hydrate airways in cystic fibrosis; discontinued in 2011 after the TIGER-2 Phase 3 trial failed to confirm lung-function benefit.

Dexloxiglumide

Dexloxiglumide (CR-2017), the (R)-isomer of loxiglumide, is a selective CCK1/CCKA receptor antagonist developed by Rotta for IBS-C; it accelerates gastric emptying but failed large phase 3 IBS trials.

Dibunic acid

Dibunic acid, also called 2,6-di-tert-butylnaphthalene-1-sulfonic acid, is the parent acid of sodium dibunate (CAS 14992-59-7, L-1633, Becantex), a non-opioid antitussive, ATC R05DB16, for non-productive cough.

Dicycloverine

Dicycloverine, also called dicyclomine (Bentyl, Merbentyl), is a synthetic antimuscarinic antispasmodic (ATC A03AA07) for gastrointestinal smooth muscle spasm, mainly IBS; effective versus placebo in one 1981 RCT but with anticholinergic side effects and contraindicated in infants under 6 months and nursing mothers.

Difemerine

Difemerine (difemerin, Luostyl) is a synthetic tertiary-amine anticholinergic antispasmodic, ATC A03AA09, formula C20H25NO3, withdrawn in Germany in 1986 for frequent adverse effects.

Difenoxin

Difenoxin, also called difenoxin hydrochloride, brand Motofen, is a phenylpiperidine antidiarrheal, active metabolite of diphenoxylate, chemically related to meperidine, marketed with atropine sulfate as a Schedule IV prescription tablet.

Diphemanil

Diphemanil, sold as Prantal, is a synthetic quaternary ammonium anticholinergic drug that blocks muscarinic receptors to reduce stomach acid, saliva, and sweat; it was used for peptic ulcer and is now discontinued.

Diphenidol

Diphenidol (difenidol; Vontrol, Cephadol) is a non-phenothiazine antiemetic and antivertigo tertiary alcohol drug, approved in the US in 1967 and now discontinued there, still used in Japan for vertigo.

Docusate

Docusate (Dulcoease, Dioctyl, Colace) is an anionic surfactant stool softener laxative for constipation, given orally or as an enema; trials show it is no more effective than placebo and inferior to psyllium.

Dolasetron

Dolasetron (Anzemet), a pseudopelletierine-derived 5-HT3 antagonist antiemetic converted to hydrodolasetron, approved 1997; oral form remains for CINV prevention, IV withdrawn over QTc prolongation.

Domperidone

Domperidone (Motilium) is a peripheral dopamine D2 antagonist antiemetic and prokinetic, synthesized 1974, marketed 1982; unapproved in the US, EU-restricted to 30 mg/day for nausea and vomiting over cardiac QT risks.

Dornase alfa

Dornase alfa (Pulmozyme), recombinant human DNase I inhaled daily, is a mucolytic for cystic fibrosis lung disease; FDA-approved 1993, it cleaves extracellular DNA in sputum, improving FEV1 and reducing exacerbations.

Doxofylline

Doxofylline, a xanthine bronchodilator introduced in 1987 as a theophylline alternative, treats asthma and COPD with bronchodilator and anti-inflammatory activity, a wider therapeutic window, no plasma monitoring, and weak PDE2A/A2A effects only.

Dropropizine

Dropropizine (UCB 1967, Ditustat, Catabex) is a racemic non-opioid peripheral antitussive, ATC R05DB19, C13H20N2O2, sold as the racemate or as the enantiomer levodropropizine; not available in the United States.

Drotaverine

Drotaverine (No-Spa, Drotin) is a Hungarian benzylisoquinoline antispasmodic, a PDE4 inhibitor related to papaverine, used for gastrointestinal, biliary, and urinary smooth muscle spasms; half-life about 9 hours, not FDA or EMA approved.

Dyphylline

Dyphylline (diprophylline, dihydroxypropyltheophylline; brands Lufyllin, Dilor, Neothylline) is a theophylline-derivative xanthine bronchodilator for asthma and COPD, excreted unchanged by the kidneys, FDA-approved 1951 and later discontinued in the US.

Ebrotidine

Ebrotidine (FI-3542, CAS 100981-43-9) is an H2-receptor antagonist antiulcer drug with added cytoprotective and anti-Helicobacter pylori activity, tested in phase II and III trials against ranitidine for peptic ulcer.

Ecabet

Ecabet is a diterpenoid anti-ulcer drug, marketed in Japan as ecabet sodium, taken orally for gastric ulcers and gastritis and studied for eliminating H. pylori.

Elexacaftor

Elexacaftor (VX-445) is a CFTR corrector used with tezacaftor and ivacaftor as Trikafta/Kaftrio for cystic fibrosis; FDA-approved 2019, binds TMD1/TMD2 site, boxed liver-injury warning.

Elobixibat

Elobixibat (A3309, GOOFICE) is a first-in-class ileal bile acid transporter inhibitor for chronic constipation, approved in Japan in January 2018; dosed 10 mg daily, it raises colonic bile acids, with abdominal pain and diarrhea as main adverse effects.

Eluxadoline

Eluxadoline (Viberzi, Truberzi) is a gut-restricted mixed mu/kappa opioid agonist and delta antagonist approved in 2015 for irritable bowel syndrome with diarrhea; 75-100 mg twice daily, contraindicated without a gallbladder.

Eno (drug)

Eno (Eno Fruit Salt) is an effervescent antacid powder of sodium bicarbonate, sodium carbonate, and citric acid, invented by James Crossley Eno in 1850s Newcastle, owned by Haleon, and a leading acidity-relief brand in India, Brazil, and other markets.

Ensifentrine

Ensifentrine (RPL554), marketed as OHTUVAYRE, is an inhaled dual PDE3/PDE4 inhibitor approved by the FDA in 2024 for maintenance treatment of COPD in adults, dosed 3 mg twice daily by jet nebulizer.

Erdosteine

Erdosteine, a thiol-based mucoactive prodrug (N-(carboxymethylthioacetyl)-homocysteine thiolactone) activated to metabolite M1, treats acute and chronic pulmonary disease; RESTORE showed reduced COPD exacerbation rate and duration.

Esomeprazole

Esomeprazole (Nexium) is the S-enantiomer of omeprazole, a proton pump inhibitor launched by AstraZeneca in 2000 that irreversibly blocks the gastric H+/K+-ATPase; used for GERD, erosive esophagitis, H. pylori eradication, and hypersecretory conditions.