Fbx

Fbx Uses, Dosage, Side Effects, Food Interaction and all others data.

Fbx is a non-purine, selective xanthine oxidase (XO) inhibitor. It decreases serum uric acid level by inhibiting xanthine oxidase, which is responsible for uric acid production. Xanthine oxidase breaks down hypoxanthine to xanthine and thus to uric acid. Fbx is not expected to inhibit other enzymes involved in purine and pyrimidine synthesis and metabolism at therapeutic concentrations.

Fbx is a novel, selective xanthine oxidase/dehydrogenase inhibitor that works by decreasing serum uric acid in a dose-dependent manner. In healthy subjects, febuxostat decreased the mean serum uric acid and serum xanthine concentrations, as well as the total urinary uric acid excretion. Fbx at daily doses of 40-80 mg reduced the 24-hour mean serum uric acid concentrations by 40 to 55%. Closely related to the drug-induced reduction of serum uric acid levels and mobilization of urate crystals in tissue deposits, febuxostat is associated with gout flares.

Unlike allopurinol and oxypurinol, febuxostat has no inhibitory actions against other enzymes involved in purine and pyrimidine synthesis and metabolism, because it does not structurally resemble purines or pyrimidines.

Trade Name Fbx
Availability Prescription only
Generic Febuxostat
Febuxostat Other Names Fébuxostat, Febuxostat, Febuxostatum
Related Drugs allopurinol, Zyloprim, probenecid, Uloric, Krystexxa
Type Tablet
Formula C16H16N2O3S
Weight Average: 316.375
Monoisotopic: 316.088163078
Protein binding

Febuxostat is approximately 99.2% bound to plasma proteins, primarily to albumin. Plasma protein binding is constant over the concentration range achieved with 40 mg and 80 mg doses.

Groups Approved
Therapeutic Class Drugs used in Gout
Manufacturer Albert David Limited
Available Country India
Last Updated: September 19, 2023 at 7:00 am
Fbx
Fbx

Uses

Fbx is used for the long-term management of Hyperuricemia in patients with gout. It is not recommended for use in the treatment of asymptomatic Hyperuricemia.

Fbx is also used to associated treatment for these conditions: Chronic, symptomatic Hyperuricemia

How Fbx works

Gout is a form of acute arthritis that is characterized by the accumulation of crystals of monosodium urate and urate crystals in or around a joint, leading to inflammation and persistent urate crystal deposition in bones, joints, tissues, and other organs that may exacerbate over time. Hyperuricemia is closely related to gout, whereby it may exist for many years before the first clinical attack of gout; thus, aberrated serum uric acid levels and hyperuricemia are believed to be the biochemical aberration involved in the pathogenesis of gout. Xanthine oxidoreductase (XOR) can act as a xanthine oxidase or xanthine dehydrogenase. In humans, it is a critical enzyme for uric acid production as it catalyzes the oxidation reaction steps from hypoxanthine to xanthine and from xanthine to uric acid in the pathway of purine metabolism. Fbx potently inhibits XOR, blocking both its oxidase and dehydrogenase activities. With high affinity, febuxostat binds to XOR in a molecular channel leading to the molybdenum-pterin active site, where allopurinol demonstrates relatively weak competitive inhibition.

XOR is mainly found in the dehydrogenase form under normal physiological conditions; however, in inflammatory conditions, XOR can be converted into the xanthine oxidase form, which catalyzes reactions that produce reactive oxygen species (ROS), such as peroxynitrite. ROS contribute to vascular inflammation and alterations in vascular function. As febuxostat can inhibit both forms of XOR, it can inhibit ROS formation, oxidative stress, and inflammation. In a rat model, febuxostat suppressed renal ischemia-reperfusion injury by attenuating oxidative stress.

Dosage

Fbx dosage

The recommended starting dosage of Fbx is 40 mg once daily. For patients who do not achieve a serum uric acid concentration of less than 6 mg/dL after 2 weeks at the 40 mg dose, Fbx 80 mg once daily is recommended. Fbx can be administered without regard to food or antacid use.

Side Effects

The most common adverse events associated with the use of Fbx may include liver function abnormalities, nausea, arthralgia, and rash.

Toxicity

Oral lowest published toxic dose (TDLO) in humans is 1.82 mg/kg/14D (intermittent). Oral LD50 is 300 mg/kg in mice, 3200 mg/kg in rabbits, and 980 mg/kg in rats.

No dose-limiting toxicities were observed with febuxostat administered at doses up to 300 mg daily for seven days in healthy subjects. There are no reports of overdose of febuxostat in clinical studies and there is no known antidote. Overdose should be managed by symptomatic and supportive care.

Precaution

Gout Flare: An increase in gout flares is frequently observed during initiation of anti-hyperuricemic agents, including Fbx. If a gout flare occurs during treatment, Fbx need not be discontinued. Prophylactic therapy (i.e., non-steroidal anti-inflammatory drug (NSAID) or colchicine upon initiation of treatment) may be beneficial for up to six months.

Cardiovascular Events: A higher rate of cardiovascular thromboembolic events was observed in patients treated with febuxostat than allopurinol in clinical trials. Monitor for signs and symptoms of MI and stroke.

Liver Enzyme Elevation: Transaminase elevations have been observed in febuxostat -treated patients. Monitor liver function tests periodically.

Interaction

Concomitant administration of Fbx with azathioprine, mercaptopurine or theophylline could increase plasma concentrations of these drugs resulting in severe toxicity.

Food Interaction

  • Take with or without food. A high fat meal decreases Cmax and AUC in a clinically insignificant way.

Volume of Distribution

The apparent steady-state volume of distribution (Vss/F) of febuxostat ranges from 29 to 75 L, indicating a low to medium volume of distribution.

Elimination Route

After oral administration, about 85% of febuxostat is absorbed rapidly. Tmax ranges from 1 to 1.5 hours. Following once-daily oral administration, Cmax was approximately 1.6 ± 0.6 mcg/mL at a dose of 40 mg febuxostat and 2.6 ± 1.7 mcg/mL at a dose of 80 mg febuxostat.

A high-fat meal decreased Cmax by 49% and AUC by 18%, but there were no clinically significant changes in the ability of febuxostat to decrease serum uric acid concentrations.

Half Life

The apparent mean terminal elimination half-life of approximately 5 to 8 hours.

Clearance

Following oral administration of single doses of 10 to 240 mg, the mean apparent total clearance ranged from 10 to 12 L/h.

Elimination Route

Fbx is eliminated via both hepatic and renal pathways. Following oral administration of 80 mg radiolabeled febuxostat, approximately 49% of the dose was recovered in the urine. In urine, about 3% of the recovered dose accounted for unchanged febuxostat, 30% accounted for the acyl glucuronide metabolite, 13% accounted for oxidative metabolites and their conjugates, and 3% accounted for unidentified metabolites.

Approximately 45% of the total dose was recovered in the feces, where 12% of the dose accounted for the unchanged parent drug. About 1% accounted for the acyl glucuronide metabolite, 25% accounted for oxidative metabolites and their conjugates, and 7% accounted for unidentified metabolites.

Pregnancy & Breastfeeding use

Pregnancy Category C. There are no adequate and well-controlled studies in pregnant women. Fbx should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Lactation: It is not known whether this drug is excreted in human milk. Caution should be exercised when Fbx is administered to a nursing woman.

Contraindication

Fbx is contraindicated in patients being treated with azathioprine, mercaptopurine, or theophylline.

Special Warning

Pediatric Use: Safety and effectiveness in pediatric patients under 18 years of age have not been established

Acute Overdose

Febustat was studied in healthy subjects in doses up to 300 mg daily for seven days without evidence of dose-limiting toxicities.

Storage Condition

Keep out of the reach of children. Keep in a cool & dry place, protected from light.

Innovators Monograph

You find simplified version here Fbx

Fbx contains Febuxostat see full prescribing information from innovator Fbx Monograph, Fbx MSDS, Fbx FDA label

FAQ

How safe is Fbx?

Fbx is a medication used long-term to treat gout due to high uric acid levels. It is generally recommended only for people who cannot take allopurinol.

How safe is Fbx?

Take one tablet each day. There have been a few reports of Fbx causing a serious allergic reaction. Although this is rare, if you experience any of these symptoms, you should stop taking Fbx and contact your doctor straightaway.

How does Fbx work?

Fbx works by decreasing the amount of uric acid that is made in the body.

What are the common side effects of Fbx?

Common side effects of Fbx are include:

  • Arm, back, or jaw pain
  • black, tarry stools
  • bloody nose
  • blurred vision
  • chest pain or discomfort
  • chills
  • cloudy urine
  • confusion
  • cough
  • dark urine
  • decreased frequency or amount of urine
  • diarrhea
  • difficult or labored breathing
  • difficulty with moving
  • dizziness
  • dry mouth
  • fainting
  • fast, irregular, pounding, or racing heartbeat or pulse
  • feeling of fullness
  • fever

Is Fbx safe during pregnancy?

Some experts advise against use during pregnancy as the potential risk for humans is unknown.

Is Fbx safe during breastfeeding?

There are no data on the effects of this drug on the breastfed infant or its effects on milk production. Some experts advise against breastfeeding as a risk to the breastfeeding infant cannot be excluded.

Can I drink alcohol with Fbx?

Alcohol doesn't interact significantly with Fbx, but it does increase the level of urate in the blood.

Can I drive after taking Fbx ?

Be aware that you may experience dizziness, sleepiness, blurred vision and numbness or tingling sensation during treatment and should not drive or operate machines, if affected.

When is the best time to take Fbx?

It is best taken in the morning. If you do shift work or want to take your medicine at night, talk to your doctor, nurse or pharmacist.

Can I take Fbx on an empty stomach?

You can take Fbx with or without food.

How long does Fbx take to work?

Fbx should be taken every day to prevent a gout attack. It can take six months to become fully effective. It does not have any effect during a gout attack, although you should continue to take it regularly every day even if this happens.

Does Fbx affect the liver?

No instances of acute liver failure or chronic liver injury have been reported due to Fbx, but the clinical experience with this agent is limited.

Can I take Fbx for a long time?

Treatment with Fbx is usually long-term unless you experience an adverse effect. Continue to take the tablets unless you are advised otherwise by a doctor.

Is Fbx bad for my heart?

Fbx does not increase or decrease the risk of cardiovascular disease but may increase the risk of CVD death.

Is Fbx bad for kidney?

Fbx has shown to be safe and effective in patients with moderate to severe renal impairment, and dose adjustment is not required in these patients.

Can Fbx be stopped?

You should not stop using Fbx suddenly.

What happen If I stop taking Fbx?

If Fbx treatment is stopped there is a high risk that your gout may worsen. You should continue to take it even if you do not have symptoms.

Who should not take Fbx?

Taking Fbx may increase your risk of serious or fatal heart problems. Seek medical attention if you have chest pain, trouble breathing, fast heartbeats, sudden severe headache, numbness or weakness on one side of your body, or problems with vision or speech. You should not use Fbx if you also use azathioprine or mercaptopurine.

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

What happen if I take too much Fbx?

If you take too much Fbx, call your healthcare provider or local Poison Control Center or seek emergency medical attention right away. If Fbx is administered by a healthcare provider in a medical setting, it is unlikely that an overdose will occur. However, if an overdose is suspected, seek emergency medical attention.

Will Fbx affect my fertility?

The effects of Fbx  on fertility are not currently known, but it's unlikely to be harmful.

*** Taking medicines without doctor's advice can cause long-term problems.
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