Clinical data
AHFS/Drugs.comInternational Drug Names
Routes of
Oral, transdermal
ATC code
Legal status
Legal status
  • JP: Class 1 OTC
    BR: Red Stripe (Rx only)
Pharmacokinetic data
Protein binding97%
MetabolismLiver glucuronidation
Elimination half-life75 minutes
  • (RS)-2-{4-[(2-oxocyclopentyl)methyl]phenyl}propanoic acid
CAS Number
PubChem CID
CompTox Dashboard (EPA)
Chemical and physical data
Molar mass246.306 g·mol−1
3D model (JSmol)
ChiralityRacemic mixture
  • O=C2C(Cc1ccc(cc1)C(C(=O)O)C)CCC2
  • InChI=1S/C15H18O3/c1-10(15(17)18)12-7-5-11(6-8-12)9-13-3-2-4-14(13)16/h5-8,10,13H,2-4,9H2,1H3,(H,17,18) checkY
 ☒NcheckY (what is this?)  (verify)

Loxoprofen is a nonsteroidal anti-inflammatory drug (NSAID) in the propionic acid derivatives group, which also includes ibuprofen and naproxen among others. It is available in some countries for oral administration. A transdermal preparation was approved for sale in Japan in January 2006;[1] medicated tape and gel formulations followed in 2008 and 2010.

It was patented in 1977 and approved for medical use in 1986.[2]


Loxoprofen is a prodrug. It is quickly converted to its active trans-alcohol metabolite following oral administration, and reaches its peak plasma concentration within 30 to 50 minutes.

Mechanism of action

As most NSAIDs, loxoprofen is a non-selective cyclooxygenase inhibitor, and works by reducing the synthesis of prostaglandins from arachidonic acid.


Loxoprofen should not be administered at the same time as second-generation quinolone antibiotics such as ciprofloxacin and norfloxacin, as it increases their inhibition of GABA and this may cause seizures.[3] It may also increase the plasma concentration of warfarin, methotrexate, sulfonylurea derivatives and lithium salts, so care should be taken when loxoprofen is administered to patients taking any of these drugs.[3]

Brand names

It is marketed in Brazil, Mexico, China and Japan by Sankyo as its sodium salt, loxoprofen sodium, under the trade name Loxonin; in Argentina as Oxeno; in India as Loxomac; in Thailand as Japrolox; and in Saudi Arabia as Roxonin and Roxonin Tape.

A generic drug is marketed in Brazil by Aché as Oxotron. In Japan, two fixed dose combinations are available: Loxonin S Plus, with magnesium oxide, and Loxonin S Premium, with apronal, caffeine, and aluminium magnesium silicate.


  1. ^ Daiichi Sankyo Co. (January 24, 2006). "Percutaneous Absorption-Type Analgesic and Anti-inflammatory Drug Loxonin Poultice 100mg Receives Approval for Manufacture" (Press release). Doctor's Guide Global Edition. Retrieved 2007-04-19.
  2. ^ Fischer J, Ganellin CR (2006). Analogue-based Drug Discovery. John Wiley & Sons. p. 521. ISBN 9783527607495.
  3. ^ a b "LOXONIN - Bula do Medicamento [Label Information]" (in Portuguese). Centralx. 2007. Retrieved 2007-04-19.