Clinical Uses of Folic Acid

Introduction

Folic acid (pregnancy category A) is a form of the vitamin B9 and acts as a blood-modifying agent by stimulating the hematopoietic system. Folate, the natural form of folic acid, is found in food, while folic acid is produced by chemical processes to be used commercially in supplementation and foods. Folic acid alone is not pharmacologically active, its activity is due to tetrahydrofolate after conversion by the liver to dihydrofolic acid. Foods that contain high amounts of folic acid include green vegetables (such as lettuce, broccoli and spinach), celery, lentils, whole-wheat products, fruits (such as lemons and bananas), beans, mushrooms, yeast, organ meats (such as sheep liver, heart and kidney) and in fresh fruits juices such as orange juice and tomato juice.

Vitamin B9(folic acid folate) plays an important role in manybodily functions. Because humans are unable to synthesise folate, it has to be obtained through the diet to meet the normal daily requirements. Our bodies need folate for DNA synthesis and repair, as well as to assist in certain biological reactions. It is particularly important in assisting rapidcell divisionandgrowth, such as in infancy and pregnancy where dietary intake is insufficient to meet daily demands.It is not only adults that need folate, children also require folate toproducehealthyred blood cellsand to preventanaemia because a lack of folate in the diet can lead to folate deficiency.

Uses

• Anaemias related to nutrition- pregnancy, infancy or childhood.
• Folic acid is mainly used for the treatment and prevention of low blood levels of folic acid (called folic acid deficiency), as well as associated complications such as macrocytic and megaloblastic anaemia.
• * Megaloblastic macrocytic anaemia: Folic acid 1mg daily and if blood count restored (√ anaemia) BUT if associated decreased vit B12 – no improvement in neurological defects therefore never use folic acid alone unless vitamin B12 confirmed as normal.
• Folic acid deficiency can also give rise to conditions such as; liver disease, kidney dialysis and ulcerative colitis which can be treated with folic acid.
• Folic acid can also be used to prevent certain types of cancers such as colon cancer or cervical cancer. It is also used to prevent cardiovascular disease by means of decreasing a chemical called homocysteine in the blood. High levels of homocysteine is associated with a risk of heart disease.
• Less common uses of folic acid; memory loss, Alzheimer’s disease, depression, to reduce signs of aging, osteoporosis, restless leg syndrome, sleeping problems, nerve & muscle pain and vitiligo (skin condition).
• It is also used for reducing potentially harmful adverse effects of medications such as methotrexate.
• Folic acid should be used in combination when drugs that cause folate deficiency are being taken. These drugs include; phenytoin, OC pill, isoniazid, methotrexate, pyrimethamine, cotrimoxazole.

Use in  Obstetrics Ward

The Centres for Disease Control and Prevention (CDC) recommends that, “all women of childbearing age and especially those who are planning a pregnancy should receive about 400 mcg (0.4 mg) of folic acid every day.” To receive adequate amounts of folic acid is very important before conception and for at least the first trimester of pregnancy because it can potentially reduce dramatically the risk of having a foetus with a neural tube defect.

• Pregnant or women who intend on becoming pregnant should take folic acid to prevent miscarriage and neural tube defects/birth defects such as spina bifida- a condition that occur when the foetus’s spine and back don’t close during development.

The most common neural tube defects that potentially could occur are:

• encephalocele- a condition that is characterised by brain tissue projecting out to the skin from an abnormal opening in the skull,
• anencephaly- severe underdevelopment of the brain,
• spina bifida, when parts of the spinal cord and spinal column are not fully formed and remain open as mentioned above.

All of the neural tube defects occur during the first 28 days of pregnancy– usually before a woman even realises she’s pregnant. Adding to the importance for all women to get sufficient folic acid and not just those who are planning to become pregnant because unplanned surprises do occur.

Lack of folate during pregnancy may potentially also increase the risk of premature delivery, low birth weight and retardation of foetal growth, as well as depleting the mechanism by which folate decreases the levels of homocysteine in the blood which may lead to fatal events such as spontaneous abortion and pregnancy complications including membrane rupture and pre-eclampsia toxemia (common in the obstetrics ward at Dora Nginza Hospital). By using vitamin B12 as a cofactor, folic acid can normalise abnormal homocysteine levels.

Mechanism of Action- how does it work?

Folic acid is rapidly absorbed from the GI tract following oral administration and is absorbed mainly in the small intestine.

Following oral administration, peak blood levels occur within 30 to 60 minutes. Synthetic folate has almost 100% bioavailability when administered in fasting individuals. While the bioavailability of naturally occurring folate found in food is approximately 50%.

Folic acid is metabolically inactive, it first has to be converted to tetrahydrofolic acid and methyltetrahydrofolate by the enzyme dihydrofolate reductase. Tetrahydrofolic acid and methyltetrahydrofolate are transported across the cells of the body by certain mechanisms to places where they are needed to maintain normal erythropoiesis (production of red blood cells) and synthesis of nucleic acids among other activities.

Side Effects

• sleep problems
• nausea, loss of appetite
• bitter or unpleasant taste in your mouth
• abdominal cramps
• diarrhoea
• rash (skin reactions)
• bloating, gas
• depression; or
• feeling excited or irritable

Not likely if dose within normal RDA of 400mcg.

Contraindications

Pernicious anaemia (unless already treated with vitamin B12

Special Points

All women planning a pregnancy should be advised strongly to take folic acid supplementation (0.4 mg daily is recommended) before conception and during the first trimester, to achieve a combined dietary and supplemental intake of 600mcg/day during pregnancy.

Also, in patients with poor nutrition, supplementation is recommended to prevent maternal folic deficiency and megaloblastic anaemia.

N.B Do not give folic acid alone in the treatment if pernicious anaemia. Vitamin B12 should be given immediately to prevent neurological damage. If there is associated vitamin B12 deficiency, the anaemia may improve while irreversible neurological damage from vitamin B12 deficiency may occur.

Nursing Considerations

CLINICAL ALERT!

There has been confusion reported about the naming between folinic acid (leucovorin) and folic acid therefore these 2 agents should be treated with extreme caution.

Assessment & Drug Effects

• The nurse should obtain a detailed history of the dietary intake, drug and alcohol usage of the patient prior to start of therapy.
• Monitor the patient’s response to therapy and inform the doctor.
• Monitor patients on interacting drugs such as phenytoin for subtherapeutic plasma levels. Women who are receiving antiepileptic therapy need individual counselling before starting folic acid.
• The patient & family should be educated appropriately.
• The use of vitamins as general ‘pick-me-ups’ is unproven and in the clinical setting they should only be prescribed to prevent or to treat deficiency.
• Women who are planning a pregnancy should to take folic acid daily before conception to prevent occurrence of neural tube defects.
• Women who suspect they are pregnant should be counselled to start supplementation immediately if they’re not doing so already.
• Detailed patient and family history should be taken. All information could be vital in preventing certain complications because a woman who has previously had a child with a neural tube defect is at a higher risk of having a baby with a neural tube defect; if she herself has a neural tube defect; if her partner or a close relative has a neural tube defect; or if she has epilepsy. In these cases higher doses of folic acid are recommended.
• DO NOT MIX FOLIC ACID WITH OTHER MEDICATIONS IN THE SAME SYRINGE and hypersensitivity reactions should be reported.