fenoprofen fenoprofen fenoprofen is a nonsteroidal anti-inflammatory drug (nsaid). fenoprofen calcium is used for symptomatic relief for rheumatoid arthritis, osteoarthritis, and mild to moderate pain. it has also been used to treat postoperative pain. fenoprofen is marketed in the us as nalfon. it is available as a generic medication. fenoprofenclinical datatrade namesnalfonahfs/drugs.commonographmedlineplusa681026pregnancycategory c routes ofadministrationby mouthatc codem01ae04 (who) legal statuslegal status uk: pom (prescription only) us: ℞-only pharmacokinetic datametabolismmajor urinary metabolites are fenoprofen glucuronide and 4′-hydroxyfenoprofen glucuronide.elimination half-life3 hoursexcretionrenal (~90%)identifiers iupac name 2-(3-phenoxyphenyl)propanoic acid cas number29679-58-1 ypubchem cid3342iuphar/bps4820drugbankdb00573 ychemspider3225 yuniira33eac7kykeggd02350 ychebichebi:5004 ychemblchembl1297 ycomptox dashboard (epa)dtxsid9023045 echa infocard100.045.231 chemical and physical dataformulac15h14o3molar mass242.274 g·mol−13d model (jsmol)interactive image smiles o=c(o)c(c2cc(oc1ccccc1)ccc2)c inchi inchi=1s/c15h14o3/c1-11(15(16)17)12-6-5-9-14(10-12)18-13-7-3-2-4-8-13/h2-11h,1h3,(h,16,17) ykey:rdjgllicxdhjdy-uhfffaoysa-n y (verify) pharmacology decreases inflammation, pain, and fever, probably through inhibition of cyclooxygenase (cox-2 inhibitor) activity and prostaglandin synthesis. chirality and biological activity fenoprofen is chiral drug with one stereogenic center and exists as chiral twins. (s)-enantiomer has the desired pharmacological action where as the (r)-isomer is less active. it is observed that there is stereoselective bioconversion of the (r)- to (s)-fenoprofen. this stereoselective conversion is called chiral inversion. contraindications history of significantly impaired renal function; patients with known hypersensitivity to any component of the product; patients who have experienced asthma, urticaria, or allergic-type reactions after taking aspirin or other nsaids; treatment of perioperative pain in the setting of coronary artery bypass graft (cabg) surgery. adverse effects in october 2020, the u.s. food and drug administration (fda) required the drug label to be updated for all nonsteroidal anti-inflammatory medications to describe the risk of kidney problems in unborn babies that result in low amniotic fluid. they recommend avoiding nsaids in pregnant women at 20 weeks or later in pregnancy. drug interactions aminoglycosides (e.g. gentamicin): plasma aminoglycoside levels may be elevated. angiotensin-converting enzyme (ace) inhibitors: antihypertensive effect of ace inhibitors may be diminished. anticoagulants: coadministration may prolong prothrombin time. aspirin: fenoprofen cl may be increased; coadministration is not recommended. diuretics: patients treated with fenoprofen may be resistant to the effects of loop diuretics and thiazides. hydantoins, sulfonamides, sulfonylureas: fenoprofen may displace these drugs from their binding site. lithium: renal cl of lithium may be reduced and plasma levels may be elevated, which may increase the risk of lithium toxicity. methotrexate: may increase methotrexate levels. phenobarbital: may decrease fenoprofen t 1⁄2 . dosage adjustments of fenoprofen may be required if phenobarbital is added or withdrawn. ssris (e.g. fluoxetine, citalopram): the risk of gi effects may be increased. laboratory test interactions false elevation in free and total serum t 3 as measured by amerlex-m kit.