Weiliufen

Uses

Weiliufen is used for:

• Rheumatoid arthritis & Juvenile arthritis: In the treatment of patients with rheumatoid arthritis and pediatiric patients with polyarticular-course juvenile rheumatoid arthritis, who have responded inadequately to salicylates or other non-steroidal anti-inflammatory drugs (NSAIDs).
• Ulcerative colitis and Crohn's Disease: As adjunct in the treatment of ulcerative colitis with the usual supportive and dietary measures. In the treatment of active Crohn's disease, especially in patients with colonic involvement.

Weiliufen is also used to associated treatment for these conditions: Crohn's Disease (CD), Polyarticular juvenile rheumatoid arthritis, chronic or unspecified, Proctitis, Rheumatoid Arthritis, Severe Ulcerative Colitis, Mild Ulcerative Colitis, Moderate Ulcerative colitis

How Weiliufen works

The mode of action of Weiliufen or its metabolites, 5-aminosalicylic acid (5-ASA) and sulfapyridine (SP), is still under investigation, but may be related to the anti-inflammatory and/or immunomodulatory properties that have been observed in animal and in vitro models, to its affinity for connective tissue, and/or to the relatively high concentration it reaches in serous fluids, the liver and intestinal walls, as demonstrated in autoradiographic studies in animals. In ulcerative colitis, clinical studies utilizing rectal administration of Weiliufen, SP and 5-ASA have indicated that the major therapeutic action may reside in the 5-ASA moiety. The relative contribution of the parent drug and the major metabolites in rheumatoid arthritis is unknown.

Dosage

Weiliufen dosage

The dosage of Weiliufen tablets should be individually adjusted according to the patient's tolerance and response to the treatment and taken in evenly divided doses preferably after meals.

Adult dose for crohn’s disease: 500 mg orally 2 to 4 times a day with food.

Pediatric use (6 years or older) for Ulcerative Colitis: The initial dose 40 to 60 mg/kg/day orally divided into 3 to 6 doses.

Adultdose for rheumatoid arthritis: 2 g daily in two evenly divided doses. It is advisable to initiate therapy with a lower dosage e.g. 0.5 to 1.0 g daily, to reduce possible gastrointestinal intolerance. A suggested dosing schedule is given bellow:

• First week: One tablet in theevening
• Secondweek: One tabletin the morning &One tabletin the evening
• Thirdweek:One tabletin the morning & two tabletin the evening
• Forthweek: Two tabletin the morning &two tabletin the evening

In case of rheumatoid arthritis 6 years or older: initial dose 10 mg/kg/day orally in 2 equally divided doses.

Juvenile rheumatoid arthritis-polyarticular course: Children 6 years of age and older: 30 to 50 mg/kg/day in two evenly divided doses. Typically the maximum dose is 2 g per day.

For other indications:

Initial therapy:

• Adults: 3 to 4 g daily in divided doses with dosage intervals not exceeding eight hours. It may be advisable to initiate therapy with a lower dosage e.g. 1 to 2 g daily to reduce possible gastrointestinal intolerance.
• Children 6 years of age and older: 40 to 60 mg/kg/day in to 3 to 6 divided doses.

Maintenance therapy:

• Adults: 2 g daily.
• Children 6 years of age and older: 30 mg/kg/day in 4 divided doses.

Side Effects

The common adverse reactions are anorexia, headache, nausea, vomiting, gastric distress, dyspepsia, abdominal pain, dizziness, apparently reversible oligospermia etc.

Precaution

Hepatic/renal impairment, G6PD deficiency, allergic bronchial asthma, lactation.

Interaction

Reduced absorption of folic acid and digoxin has been reported when those agents were administered concomitantly with sulfasalazine.

Food Interaction

• Drink plenty of fluids. Inadequate fluid intake is associated with crystalluria and stone formation.
• Take with food.

Weiliufen Drug Interaction

Moderate: celecoxibUnknown: aspirin, diphenhydramine, duloxetine, etanercept, omega-3 polyunsaturated fatty acids, cyclobenzaprine, adalimumab, pregabalin, metoprolol, esomeprazole, acetaminophen / hydrocodone, hydroxychloroquine, montelukast, levothyroxine, acetaminophen, cyanocobalamin, ascorbic acid, cholecalciferol, cetirizine

Weiliufen Disease Interaction

Major: colitis, intestinal obstruction, urinary obstruction, hematologic toxicity, hypersensitivity reactions, liver disease, porphyria, renal dysfunctionModerate: renal dysfunction, folate deficiency, G6PD deficiency, crystalluria

Volume of Distribution

• 7.5 ± 1.6 L

Half Life

5-10 hours

Clearance

• 1 L/h [IV administration]

Elimination Route

The majority of 5-ASA stays within the colonic lumen and is excreted as 5-ASA and acetyl-5-ASA with the feces.

Pregnancy & Breastfeeding use

Use in pregnancy: Pregnancy category B. This drug should be used during pregnancy only if clearly needed.

Use in lactation: Caution should be exercised when sulfasalazine is administered to a nursing mother.

Contraindication

Hypersensitivity to Weiliufen, its metabolites, sulfonamides or salicylates, patients with intestinal or urinary obstruction and porphyria.

Storage Condition

Store in a cool and dry place, protected from light.

Innovators Monograph

You find simplified version here Weiliufen