ANTICONVULTANTS DRUGS AND INTERACTIONS

[Guest guest]

Interactions with Dietary Supplements

Biotin

Several controlled studies have shown that long-term anticonvulsant

treatment decreases blood levels of biotin.1 2 3 4 In children, a

deficiency of biotin can lead to withdrawn behavior and a delay in

mental development. Adults with low biotin levels might experience a

loss of appetite, feelings of discomfort or uneasiness, mental

depression, or hallucinations. To avoid side effects, individuals

taking anticonvulsants should supplement with biotin either alone or

as part of a multivitamin.

Calcium

Individuals on long-term multiple anticonvulsant therapy may develop

below-normal blood levels of calcium, which may be related to drug-

induced vitamin D deficiency.5 Two infants born to women taking high

doses of phenytoin and phenobarbital while pregnant developed

jitteriness and tetany (a syndrome characterized by muscle twitches,

cramps, and spasm) during the first two weeks of life.6 Controlled

research is needed to determine whether pregnant women who are

taking anticonvulsant medications should supplement with additional

amounts of calcium and vitamin D.

L-Carnitine

Several controlled and preliminary studies showed that multiple drug

therapy for seizures results in dramatic reductions in blood

carnitine levels.7 8 9 Further controlled research is needed to

determine whether children taking anticonvulsants might benefit by

supplementing with L-carnitine, since current studies yield

conflicting results. For example, one controlled study indicated

that children taking valproic acid and carbamazepine received no

benefit from supplementing with L-carnitine.10 However, another

small study revealed that children taking valproic acid experienced

less fatigue and excessive sleepiness following L-carnitine

supplementation.11 Despite the lack of well-controlled studies,

individuals who are taking anticonvulsants and experiencing side

effects might benefit from supplementing with L-carnitine.

Folic acid

Several studies have shown that multiple anticonvulsant therapy

reduces blood levels of folic acid and dramatically increases

homocysteine levels.12 13 14 Homocysteine, a potential marker for

folic acid deficiency, is a compound used experimentally to induce

seizures and is associated with atherosclerosis. Carbamazepine alone

has also been shown to reduce blood levels of folic acid.15

One preliminary study showed that pregnant women who use

anticonvulsant drugs without folic acid supplementation have an

increased risk of having a child with birth defects, such as heart

defects, cleft lip and palate, neural tube defects, and skeletal

abnormalities. However, supplementation with folic acid greatly

reduces the risk.16 Consequently, some healthcare practitioners

recommend that women taking multiple anticonvulsant drugs supplement

with 5 mg of folic acid daily, for three months prior to conception

and during the first trimester, to prevent folic acid deficiency-

induced birth defects.17 Other practitioners suggest that 1 mg or

less of folic acid each day is sufficient to prevent deficiency

during pregnancy.18

One well-controlled study showed that adding folic acid to multiple

anticonvulsant therapy resulted in reduced seizure frequency.19 In

addition, three infants with seizures who were unresponsive to

medication experienced immediate relief following supplementation

with the active form of folic acid.20

Despite the apparent beneficial effects, some studies have indicated

that as little as 0.8 mg of folic acid taken daily can increase the

frequency and/or severity of seizures.21 22 23 24 However, a recent

controlled study showed that both healthy and epileptic women taking

less than 1 mg of folic acid per day had no increased risk for

seizures.25 Until more is known about the risks and benefits of

folic acid, individuals taking multiple anticonvulsant drugs should

consult with their healthcare practitioner before supplementing with

folic acid. In addition, pregnant women or women who might become

pregnant while taking anticonvulsant drugs should discuss folic acid

supplementation with their practitioner.

Vitamin A

Anticonvulsant drugs can occasionally cause birth defects when taken

by pregnant women, and their toxicity might be related to low blood

levels of vitamin A. One controlled study showed that taking

multiple anticonvulsant drugs results in dramatic changes in the way

the body utilizes vitamin A.26 Further controlled research is needed

to determine whether supplemental vitamin A might prevent birth

defects in children born to women on multiple anticonvulsant

therapy. Other research suggests that ingestion of large amounts of

vitamin A may promote the development of birth defects, although the

studies are conflicting.

Vitamin B6

One controlled study revealed that taking anticonvulsant drugs

dramatically reduces blood levels of vitamin B6.27 A nutritional

deficiency of vitamin B6 can lead to an increase in homocysteine

blood levels, which has been associated with atherosclerosis.

Vitamin B6 deficiency is also associated with symptoms such as

dizziness, fatigue, mental depression, and seizures. On the other

hand, supplementation with large amounts of vitamin B6 (80–200 mg

per day) has been reported to reduce blood levels of some

anticonvulsant drugs, which could theoretically trigger seizures.

People taking multiple anticonvulsant drugs should discuss with

their doctor whether supplementing with vitamin B6 is advisable.

Vitamin B12

Anemia is an uncommon side effect experienced by people taking

anticonvulsant drugs. Though many researches believe that low blood

levels of folic acid are involved, the effects might be caused by a

vitamin B12 deficiency. Deficiencies of folic acid and vitamin B12

can lead to nerve and mental problems. One study revealed that

individuals on long-term anticonvulsant therapy, despite having no

laboratory signs of anemia, had dramatically lower levels of vitamin

B12 in their cerebrospinal fluid (the fluid that bathes the brain)

when compared with people who were not taking seizure medications.

Improvement in mental status and nerve function was observed in a

majority of symptomatic individuals after taking 30 mcg of vitamin

B12 daily for a few days.28 Another study found that long-term

anticonvulsant therapy had no effect on blood levels of vitamin

B12.29 The results of these two studies indicate that people taking

anticonvulsant drugs might experience side effects of vitamin B12

deficiency, and that the deficiency is not easily detected by the

usual blood tests. Therefore, individuals taking anticonvulsant

drugs for several months or years might prevent nerve and mental

problems by supplementing with vitamin B12.

Vitamin D

Though research results vary, long-term use of anticonvulsant drugs

appears to interfere with vitamin D activity, which might lead to

softening of bones (osteomalacia). One study showed that blood

levels of vitamin D in males taking anticonvulsants were lower than

those found in men who were not taking seizure medication.30 In a

controlled study, bone strength improved in children taking

anticonvulsant drugs who were supplemented with the activated form

of vitamin D and 500 mg per day of calcium for nine months.31 Some

research suggests that differences in exposure to sunlight—which

normally increases blood levels of vitamin D—might explain why some

studies have failed to find a beneficial effect of vitamin D

supplementation. In one controlled study, blood vitamin D levels in

children taking anticonvulsants were dramatically lower in winter

months than in summer months.32 Another study of 450 people in

Florida taking anticonvulsants found that few had drug-induced bone

disease.33 Consequently, people taking anticonvulsant drugs who do

not receive adequate sunlight should supplement with 400 IU of

vitamin D each day to help prevent osteomalacia.

Vitamin E

Two studies showed that individuals taking phenytoin and

phenobarbital had lower blood vitamin E levels than those who

received no treatment for seizures.34 35 Though the consequences of

lower blood levels of vitamin E are unknown, people taking multiple

anticonvulsant drugs should probably supplement with 100 to 200 IU

of vitamin E daily to prevent a deficiency.

Vitamin K

Some studies have shown that babies born to women taking

anticonvulsant drugs have low blood levels of vitamin K, which might

cause bleeding in the infant.36 Though some researchers recommend

vitamin K supplementation prior to delivery,37 38 not all agree that

supplementation for women taking anticonvulsant drugs is

necessary.39 Until more information is available, pregnant women or

women who might become pregnant while taking anticonvulsant drugs

should discuss vitamin K supplementation with their healthcare

practitioner.

http://www.mothernature.com/Library/Ency/Index.cfm/id/1082009