indication

Flurbiprofen tablets are indicated for the acute or long-term symptomatic treatment of rheumatoid arthritis, osteorarthritis and anklosing spondylitis. It may also be used to treat pain associated with dysmenorrhea and mild to moderate pain accompanied by inflammation (e.g. bursitis, tendonitis, soft tissue trauma). Topical ophthalmic formulations may be used pre-operatively to prevent intraoperative miosis.

pharmacology

Flurbiprofen, a nonsteroidal anti-inflammatory agent (NSAIA) of the propionic acid class, is structually and pharmacologically related to fenoprofen, ibuprofen, and ketoprofen, and has similar pharmacological actions to other prototypica NSAIAs. Flurbiprofen exhibits antiinflammatory, analgesic, and antipyretic activities. The commercially available flurbiprofen is a racemic mixture of (+)S- and (-) R-enantiomers. The S-enantiomer appears to possess most of the anti-inflammatory, while both enantiomers may possess analgesic activity.

mechanism of action

Similar to other NSAIAs, the anti-inflammatory effect of flurbiprofen occurs via reversible inhibition of cyclooxygenase (COX), the enzyme responsible for the conversion of arachidonic acid to prostaglandin G2 (PGG2) and PGG2 to prostaglandin H2 (PGH2) in the prostaglandin synthesis pathway. This effectively decreases the concentration of prostaglandins involved in inflammation, pain, swelling and fever. Flurbiprofen is a non-selective COX inhibitor and inhibits the activity of both COX-1 and -2. It is also one of the most potent NSAIAs in terms of prostaglandin inhibitory activity.

toxicity

LD₅₀=10 mg/kg (orally in dogs).

Selective COX-2 inhibitors have been associated with increased risk of serious cardiovascular events (e.g. myocardial infarction, stroke) in some patients. Current data is insufficient to assess the cardiovascular risk of flurbiprofen. Flurbiprofen may increase blood pressure and/or cause fluid retention and edema. Use caution in patients with fluid retention or heart failure. Risk of GI toxicity including bleeding, ulceration and perforation. Risk of direct renal injury, including renal papillary necrosis. Anaphylactoid and serious skin reactions (e.g. exfoliative dermatitis, Stevens-Johnson syndrome, toxic epidermal necrolysis) may occur. Common adverse events include abdominal pain, constipation, diarrhea, dyspepsia, flatulence, GI bleeding, GI perforation, nausea, peptic ulcer, vomiting, renal function abnormalities, anemia, dizziness, edema, liver function test abnormalities, headache, prolonged bleeding time, pruritus, rash, tinnitus.

biotransformation

Hepatic. Cytochrome P450 2C9 plays an important role in the metabolism of flurbiprofen to its major metabolite, 4’-hydroxy-flurbiprofen. The 4’-hydroxy-flurbiprofen metabolite showed little anti-inflammatory activity in animal models of inflammation.

absorption

Fluribiprofen is rapidly and almost completely absorbed following oral administration. Peak plasma concentrations are reached 0.5 - 4 hours after oral administration.

half life

R-flurbiprofen, 4.7 hours; S-flurbiprofen, 5.7 hours

route of elimination

Flurbiprofen is poorly excreted into human milk. Following dosing with flurbiprofen, less than 3% of flurbiprofen is excreted unchanged in the urine, with about 70% of the dose eliminated in the urine as parent drug and metabolites. Renal elimination is a significant pathway of elimination of flurbiprofen metabolites.

drug interactions

Acenocoumarol: The NSAID, flurbiprofen, may increase the anticoagulant effect of acenocoumarol.

Alendronate: Increased risk of gastric toxicity

Anisindione: The NSAID, flurbiprofen, may increase the anticoagulant effect anisindione.

Colesevelam: Bile acid sequestrants may decrease the absorption of Nonsteroidal Anti-Inflammatory Agents. Monitor for decreased serum concentrations/therapeutic effects of nonsteroidal anti-inflammatory agents (NSAID) if coadministered with bile acid sequestrants. Separating the administration of doses by 2 or more hours may reduce (but not eliminate) the risk of interaction. The manufacturer of colesevelam recommends that drugs should be administered at least 1 hour before or 4 hours after colesevelam.

Cyclosporine: Monitor for nephrotoxicity

Dicumarol: The NSAID, flurbiprofen, may increase the anticoagulant effect of dicumarol.

Ginkgo biloba: Additive anticoagulant/antiplatelet effects may increase bleed risk. Concomitant therapy should be avoided.

Methotrexate: The NSAID, flurbiprofen, may decrease the renal excretion of methotrexate. Increased risk of methotrexate toxicity.

Tamoxifen: Flurbiprofen may reduce clearance rate of Tamoxifen. Monitor for changes in therapeutic/adverse effects of Tamoxifen if Flurbiprofen is initiated, discontinued or dose changed.

Telmisartan: Concomitant use of Telmisartan and Flurbiprofen may increase the risk of acute renal failure and hyperkalemia. Monitor renal function at the beginning and during treatment.

Timolol: The NSAID, Flurbiprofen, may antagonize the antihypertensive effect of Timolol.

Tolbutamide: Flurbiprofen, a strong CYP2C9 inhibitor, may decrease the metabolism and clearance of Tolbutamide, a CYP2C9 substrate. Consider alternate therapy or monitor for changes in Tolbutamide therapeutic and adverse effects if Flurbiprofen is initiated, discontinued or dose changed.

Torasemide: Flurbiprofen, a strong CYP2C9 inhibitor, may increase the serum concentration of Torasemide, a CYP2C9 substrate, by decreasing Torasemide metabolism and clearance. Consider alternate therapy or monitor for changes in the therapeutic and adverse effects of Torasemide if Flurbiprofen is initiated, discontinued or dose changed.

Trandolapril: The NSAID, Flurbiprofen, may reduce the antihypertensive effect of Trandolapril. Consider alternate therapy or monitor for changes in Trandolapril efficacy if Flurbiprofen is initiated, discontinued or dose changed.

Treprostinil: The prostacyclin analogue, Treprostinil, may increase the risk of bleeding when combined with the NSAID, Flurbiprofen. Monitor for increased bleeding during concomitant thearpy.

Trimethoprim: The strong CYP2C9 inhibitor, Flurbiprofen, may decrease the metabolism and clearance of Trimethoprim, a CYP2C9 substrate. Consider alternate therapy or monitor for changes in therapeutic and adverse effects of Trimethoprim if Flurbiprofen is initiated, discontinued or dose changed.

Voriconazole: Flurbiprofen, a strong CYP2C9 inhibitor, may increase the serum concentration of voriconazole by decreasing its metabolism. Monitor for changes in the therapeutic and adverse effects of voriconazole if flurbiprofen is initiated, discontinued or dose changed.

Warfarin: Flurbiprofen, a strong CYP2C9 inhibitor, may decrease the metabolism of warfarin. The antiplatelet effect of flurbiprofen may also increase the bleed risk associated with warfarin. Consider alternate therapy or monitor for changes in the therapeutic and adverse effects of warfarin if flurbiprofen is initiated, discontinued or dose changed.