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Medically reviewed by Militian Inessa Mesropovna, PharmD. Last updated on 05.03.2025
Attention! Information on this page is intended only for medical professionals! Information is collected in open sources and may contain significant errors! Be careful and double-check all the information on this page!
Namifen (commonly known as Vitamin B12) is the most chemically complex of all the vitamins. Namifen's structure is based on a corrin ring, which, although similar to the porphyrin ring found in heme, chlorophyll, and cytochrome, has two of the pyrrole rings directly bonded. The central metal ion is Co (cobalt). Namifen cannot be made by plants or by animals, as the only type of organisms that have the enzymes required for the synthesis of cyanocobalamin are bacteria and archaea. Higher plants do not concentrate cyanocobalamin from the soil and so are a poor source of the substance as compared with animal tissues. Namifen is naturally found in foods including meat (especially liver and shellfish), eggs, and milk products.
Carefully consider the potential benefits and risks of Namifen (Namifen) and other treatment options before deciding to use Namifen (Namifen). Use the lowest effective dose for the shortest duration consistent with individual patient treatment goals.
Namifen (Namifen) is indicated:
- For relief of mild to moderate pain in patients =14 years of age, when therapy will not exceed one week (7 days).
- For treatment of primary dysmenorrhea.
Namifen is in a group of drugs called nonsteroidal anti-inflammatory drugs (NSAIDs). Namifen works by reducing hormones that cause inflammation and pain in the body.
Namifen is used to treat pain or inflammation caused by arthritis. It is also used to treat menstrual pain.
Namifen may also be used for other purposes not listed in this medication guide.
Carefully consider the potential benefits and risks of Namifen (Namifen) and other treatment options before deciding to use Namifen (Namifen). Use the lowest effective dose for the shortest duration consistent with individual patient treatment goals.
After observing the response to initial therapy with Namifen (Namifen), the dose and frequency should be adjusted to suit an individual patient's needs.
For the relief of acute pain in adults and adolescents =14 years of age, the recommended dose is 500 mg as an initial dose followed by 250 mg every 6 hours as needed, usually not to exceed one week.
How supplied
Namifen (Namifen) is available as 250 mg blue-banded, ivory capsules, imprinted with "FHPC 400" and "Namifen® (Namifen) ".
Bottles of 100...................NDC 59630-400-10
Storage
Store at 20- 25°C (68- 77°F); excursions permitted to 15-30°C (59-86°F).
REFERENCES
4. Glazko AJ: Experimental observations of flufenamic, mefenamic, and meclofenamic acids. Part III. Metabolic disposition, in Fenamates in Medicine. A Symposium, London, 1966. Annals of Physical Medicine, Supplement, pp 23-36, 1967.
5. Data on file, First Horizon (Protocol 356).
Distributed by: Atlanta, GA 30328. Revised March 2007. FDA Rev date: 3/6/2008
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What is the most important information I should know about Namifen?
Namifen (Namifen) is contraindicated in patients with known hypersensitivity to Namifen.
Namifen (Namifen) should not be given to patients who have experienced asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDs. Severe, rarely fatal, anaphylactic-like reactions to NSAIDs have been reported in such patients.
Namifen (Namifen) is contraindicated for the treatment of peri-operative pain in the setting of coronary artery bypass graft (CABG) surgery.
Namifen (Namifen) is contraindicated in patients with acute active ulceration or chronic inflammation of either the upper or lower gastrointestinal tract.
Namifen (Namifen) should not be used in patients with preexisting renal disease.
Use Namifen as directed by your doctor. Check the label on the medicine for exact dosing instructions.
- Namifen comes with an extra patient information sheet called a Medication Guide. Read it carefully. Read it again each time you get Namifen refilled.
- Take Namifen by mouth. It may be taken with food if it upsets your stomach. Taking it with food may not lower the risk of stomach or bowel problems (eg, bleeding, ulcers). Talk with your doctor or pharmacist if you have persistent stomach upset.
- Take Namifen with a full glass of water (8 oz/240 mL) as directed by your doctor.
- If you miss a dose of Namifen and you are taking it regularly, take it as soon as possible. If it is almost time for your next dose, skip the missed dose. Go back to your regular dosing schedule. Do not take 2 doses at once.
Ask your health care provider any questions you may have about how to use Namifen.
There are specific as well as general uses of a drug or medicine. A medicine can be used to prevent a disease, treat a disease over a period or cure a disease. It can also be used to treat the particular symptom of the disease. The drug use depends on the form the patient takes it. It may be more useful in injection form or sometimes in tablet form. The drug can be used for a single troubling symptom or a life-threatening condition. While some medications can be stopped after few days, some drugs need to be continued for prolonged period to get the benefit from it.Use: Labeled Indications
Pain, mild to moderate: Relief of mild to moderate pain in patients ≥14 years, when therapy will not exceed 1 week.
Primary dysmenorrhea: Treatment of primary dysmenorrhea.
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What other drugs will affect Namifen?
A number of compounds are inhibitors of CYP2C9. Drug interactions studies of Namifen and these compounds have not been conducted. The possibility of altered safety and efficacy should be considered when Namifen (Namifen) is used concomitantly with these drugs.
ACE-inhibitors
Reports suggest that NSAIDs may diminish the antihypertensive effect of ACE inhibitors. This interaction should be given consideration in patients taking NSAIDs concomitantly with ACE-inhibitors.
Aspirin
When Namifen (Namifen) is administered with aspirin, its protein binding is reduced, although the clearance of free Namifen (Namifen) is not altered. The clinical significance of this interaction is not known; however, as with other NSAIDs, concomitant administration of Namifen and aspirin is not generally recommended because of the potential of increased adverse effects.
Diuretics
Clinical studies, as well as post marketing observations, have shown that Namifen (Namifen) can reduce the natriuretic effect-of furosemide and thiazides in some patients. This response has been attributed to inhibition of renal prostaglandin synthesis. During concomitant therapy of NSAIDs, the patient should be observed closely for signs of renal failure, as well as to assure diuretic efficacy.
Lithium
NSAIDs have produced an elevation of plasma lithium levels and a reduction in renal lithium clearance. The mean minimum lithium concentration increased 15% and the renal clearance decreased by approximately 20%. These effects have been attributed to inhibition of renal prostaglandin synthesis by the NSAID. Thus, when NSAIDs and lithium are administered concurrently, subjects should be observed carefully for signs of lithium toxicity.
Methotrexate
NSAIDs have been reported to competitively inhibit methotrexate accumulation in rabbit kidney slices. This may indicate that they could enhance the toxicity of methotrexate. Caution should be used when NSAIDs are administered concomitantly with methotrexate.
Warfarin
The effects of warfarin and NSAIDs on GI bleeding are synergistic, such that users of both drugs together have a risk of serious GI bleeding higher than users of either drug alone.
Antacids
In a single dose study (n=6), ingestion of an antacid containing 1.7-gram of magnesium hydroxide with 500-mg of Namifen increased the Cmax and AUC of Namifen by 125% and 36%, respectively. Therefore, when the drug is administered to patients receiving oral anticoagulant drugs, frequent monitoring of prothrombin time is necessary.
A false-positive reaction for urinary bile, using the diazo tablet test, may result after Namifen administration. If biliuria is suspected, other diagnostic procedures, such as the Harrison spot test, should be performed.
REFERENCES
4. Glazko AJ: Experimental observations of flufenamic, mefenamic, and meclofenamic acids. Part III. Metabolic disposition, in Fenamates in Medicine. A Symposium, London, 1966. Annals of Physical Medicine, Supplement, pp 23-36, 1967.
See also:
What are the possible side effects of Namifen?
Diarrhoea occasionally occurs following the use of Namifen. Although this may occur soon after starting of treatment, it may also occur after several months of continuous use. The diarrhoea has been investigated in some patients who have continued this drug in spite of its continued presence; these patients were found to have associated proctocolitis.
If diarrhoea does develop; the drug should be discontinued immediately and the patient should not receive Namifen again.
Skin rashes have been observed following the administration of Namifen and the occurrence of a rash is a definite indication to stop medication.
As with other prostaglandin inhibitors, allergic glomerulonephritis has occurred occasionally.
Rarely, thrombocytopenia has been reported with Namifen. In some cases reversible haemolytic anaemia has occurred with continuous administration of Namifen for 12 months or longer.
Temporary lowering of the white blood cells count has been reported. Blood studies should therefore be carried out during long term administration.
Bronchospasm may be precipitated in patients suffering from, or with a previous history of bronchial asthma or allergic disease.
Patients on prolonged therapy should also be kept under surveillance with particular attention to liver dysfunction; should this appear, it is an indication to discontinue therapy.
Drowsiness and dizziness have rarely been reported.
