Drug Information

  


   












Pharmacokinetics



Folic acid is rapidly
absorbed from the gastrointestinal tract, mainly from the duodenum and
jejunum. Dietary folates are stated to be less well absorbed than
crystalline folic acid. The naturally occurring folate polyglutamates
are largely deconjugated and reduced by dihydrofolate reductase in the
intestines to form 5-methyltetrahydrofolate, which appears in the portal
circulation, where it is extensively bound to plasma proteins. Folic
acid administered therapeutically enters the portal circulation largely
unchanged since it is a poor substrate for reduction by dihydrofolate
reductase. It is converted to the metabolically active form
5-methyltetrahydrofolate in the plasma and liver.

The principal
storage site of folate is the liver; it is also actively concentrated in
the CSF.

Folate
undergoes enterohepatic circulation. Folate metabolites are eliminated
in the urine and folate in excess of body requirements is excreted
unchanged in the urine. Folate is distributed into breast milk. Folic
acid is removed by haemodialysis.

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Indication
& Dosage




Folic acid deficiency
states eg. megaloblastic anaemias, tropical & NONTROPICAL SPRUE,
alcoholism. Adjunctive therapy in nutritional anaemias & anaemia of
pregnancy.

Dosage: Adults: Therapeutic 5-20mg daily in divided doses.

Children: 5-10mg daily ind div. dose.

Maint: 1/2 the therapeutic doses.

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Action




Folic acid (which is converted to tetrahydrofolic acid) is necessary for
normal production of RBCs and for synthesis of nucleoproteins.
Tetrahydrofolic acid is a cofactor in the biosynthesis of purines and
thymidylates of nucleic acids. Megaloblastic and macrocytic anemias in
folic acid deficiency are believed to be due to impairment of
thymidylate synthesis. Natural sources of folic acid include liver,
dried beans, peas, lentils, whole-wheat products, asparagus, beets,
broccoli, brussels sprouts, spinach, and oranges. Synthetic folic acid
is absorbed from the GI tract even if the client suffers from
malabsorption syndrome. Peak plasma levels after an oral dose: 1
hr. It is stored in the liver.

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Interaction

Aminosalicylic acid /
Serum folate levels

Corticosteroids (chronic use) /
Folic acid requirements


Methotrexate / Is a folic acid antagonist


Oral contraceptives /
Risk of folate deficiency


Phenytoin / Folic acid
seizure frequency; also, phenytoin
serum folic acid levels.


Pyrimethamine / Folic acid
effect of pyrimethamine in toxoplasmosis; also, pyrimethamine is a folic
acid antagonist


Sulfonamides /
Absorption of folic acid


Triamterene /
Utilization of folic acid as it is a folic acid antagonist


Trimethoprim /
Utilization of folic acid as it is a folic acid antagonist

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Precaution

Folic acid is
generally well tolerated. Gastrointestinal disturbances and
hypersensitivity reactions have been reported rarely.



Folic acid should never be given alone or in conjunction with inadequate
amounts of vitamin B(12) for the treatment of undiagnosed megaloblastic
anaemia, since folic acid may produce a haematopoietic response in
patients with a megaloblastic anaemia due to vitamin B(12) deficiency
without preventing aggravation of neurological symptoms. This masking of
the true deficiency state can lead to serious neurological damage, such
as subacute combined degeneration of the spinal cord

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Brands
available in market


 


















FOLIK

Synokem

TAB

10

5mg

7.32

tab 10 10mg 11.95

FOLINAL

TAB

10

5mg

6.60

FOLITAB

Mercury

TAB

10

5mg

6.65

FOLVITE

Wyeth
Lederle

TAB

10

5mg

6.65

MEGAFIT

Arivind
Remedies

TAB 10 5mg 7.50



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Drug Information
  

   

Pharmacokinetics

Folic acid is rapidly absorbed from the gastrointestinal tract, mainly from the duodenum and jejunum. Dietary folates are stated to be less well absorbed than crystalline folic acid. The naturally occurring folate polyglutamates are largely deconjugated and reduced by dihydrofolate reductase in the intestines to form 5-methyltetrahydrofolate, which appears in the portal circulation, where it is extensively bound to plasma proteins. Folic acid administered therapeutically enters the portal circulation largely unchanged since it is a poor substrate for reduction by dihydrofolate reductase. It is converted to the metabolically active form 5-methyltetrahydrofolate in the plasma and liver.

The principal storage site of folate is the liver; it is also actively concentrated in the CSF.

Folate undergoes enterohepatic circulation. Folate metabolites are eliminated in the urine and folate in excess of body requirements is excreted unchanged in the urine. Folate is distributed into breast milk. Folic acid is removed by haemodialysis.

Top
   

Indication & Dosage

Folic acid deficiency states eg. megaloblastic anaemias, tropical & NONTROPICAL SPRUE, alcoholism. Adjunctive therapy in nutritional anaemias & anaemia of pregnancy.
Dosage: Adults: Therapeutic 5-20mg daily in divided doses.
Children: 5-10mg daily ind div. dose.
Maint: 1/2 the therapeutic doses.

Top
   

Action

Folic acid (which is converted to tetrahydrofolic acid) is necessary for normal production of RBCs and for synthesis of nucleoproteins. Tetrahydrofolic acid is a cofactor in the biosynthesis of purines and thymidylates of nucleic acids. Megaloblastic and macrocytic anemias in folic acid deficiency are believed to be due to impairment of thymidylate synthesis. Natural sources of folic acid include liver, dried beans, peas, lentils, whole-wheat products, asparagus, beets, broccoli, brussels sprouts, spinach, and oranges. Synthetic folic acid is absorbed from the GI tract even if the client suffers from malabsorption syndrome. Peak plasma levels after an oral dose: 1 hr. It is stored in the liver.

Top
   

Interaction

Aminosalicylic acid / Serum folate levels Corticosteroids (chronic use) / Folic acid requirements Methotrexate / Is a folic acid antagonist Oral contraceptives / Risk of folate deficiency Phenytoin / Folic acid seizure frequency; also, phenytoin serum folic acid levels. Pyrimethamine / Folic acid effect of pyrimethamine in toxoplasmosis; also, pyrimethamine is a folic acid antagonist Sulfonamides / Absorption of folic acid Triamterene / Utilization of folic acid as it is a folic acid antagonist Trimethoprim / Utilization of folic acid as it is a folic acid antagonist

Top
   

Precaution

Folic acid is generally well tolerated. Gastrointestinal disturbances and hypersensitivity reactions have been reported rarely.

Folic acid should never be given alone or in conjunction with inadequate amounts of vitamin B(12) for the treatment of undiagnosed megaloblastic anaemia, since folic acid may produce a haematopoietic response in patients with a megaloblastic anaemia due to vitamin B(12) deficiency without preventing aggravation of neurological symptoms. This masking of the true deficiency state can lead to serious neurological damage, such as subacute combined degeneration of the spinal cord

Top
   

FOLIK

Synokem

TAB

10

5mg

7.32

tab

10

10mg

11.95

FOLINAL

TAB

10

5mg

6.60

FOLITAB

Mercury

TAB

10

5mg

6.65

FOLVITE

Wyeth Lederle

TAB

10

5mg

6.65

MEGAFIT

Arivind Remedies

TAB

10

5mg

7.50

Top
  

 

 

By |2022-07-20T16:43:01+00:00July 20, 2022|Uncategorized|Comments Off on Folic Acid

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