L-Methylfolate Calcium and Phenytoin Extended-Release Capsules
Determining the interaction of L-Methylfolate Calcium and Phenytoin Extended-Release Capsules and the possibility of their joint administration.
In the database of official manuals used in the service creation an interaction registered by statistical results of studies was found, which can either lead to negative consequences for the patient health or strengthen a mutual positive effect. A doctor should be consulted to address the issue of joint drug administration.
Consumer:Some anticonvulsant medications may reduce the blood levels of folic acid. In addition, folic acid treatment may reduce the blood levels of certain anticonvulsants. Talk to your doctor if you have any questions or concerns. You may need a dose adjustment or more frequent monitoring to safely use both medications. Contact your doctor if your condition changes or you experience loss of seizure control. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.
Professional:MONITOR: Anticonvulsants including, but not limited to, carbamazepine, lamotrigine, phenobarbital, phenytoin, primidone, and valproic acid have been shown to impair folate absorption and increase the metabolism of circulating folate. The precise mechanism of interaction has not been established.
MONITOR: Coadministration with folate therapy may reduce the anticonvulsant effects of phenytoin, phenobarbital, primidone, and succinimides. The exact mechanism of interaction is unknown. Available data pertain primarily to phenytoin. Some investigators suggest that folic acid may serve as a cofactor in the metabolism of phenytoin, thus clearance is increased in the presence of folic acid. In one study, administration of folic acid for 14 days reduced the serum levels of phenytoin in normal subjects without significantly altering the bound fraction. Urinary excretion of phenytoin and its metabolite, meta-hydroxydiphenylhydantoin, was increased. In another study, three of four folate-deficient male patients receiving phenytoin monotherapy for epilepsy demonstrated a 7.5% to 47.6% decrease in total phenytoin plasma concentration following the addition of folic acid 1 mg/day for 180 or 300 days. Ratios of urinary metabolites to parent drug increased in these patients, suggesting an increase in phenytoin oxidative metabolism. The interaction is further supported by case reports describing subtherapeutic phenytoin levels and/or breakthrough seizures following the addition of folate therapy, including one case involving folinic acid (leucovorin). Limited data are available for phenobarbital and primidone. In one study, the addition of folic acid 15 mg/day increased the frequency and severity of seizures in 13 of 26 folate-deficient epileptic patients receiving two or more anticonvulsant drugs, including phenytoin, phenobarbital, and primidone. Nine of them required discontinuation of folic acid therapy. No data are available for other hydantoins.
MANAGEMENT: Caution is advised when folate therapy is coadministered with anticonvulsants. Close monitoring for clinical and laboratory evidence of diminished therapeutic response to both treatments is recommended. Patients should be advised to notify their physician if they experience loss of seizure control.
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Generic Name: levomefolate calcium
Brand name:
Synonyms: n.a.
Generic Name: phenytoin
Brand name: Dilantin, Phenytek, Dilantin Infatabs, Phenytoin Sodium, Prompt
Synonyms: Phenytoin
In the course of checking the drug compatibility and interactions, data from the following reference sources was used: Drugs.com, Rxlist.com, Webmd.com, Medscape.com.
- L-Methylfolate Calcium-Phenytoin Infatabs
- L-Methylfolate Calcium-Phenytoin injection
- L-Methylfolate Calcium-Phenytoin Intravenous
- L-Methylfolate Calcium-Phenytoin Oral Suspension
- L-Methylfolate Calcium-Phenytoin Sodium
- L-Methylfolate Calcium-Phenytoin Sodium, Prompt injection
- Phenytoin Extended-Release Capsules-L-Methylfolate Formula
- Phenytoin Extended-Release Capsules-L-Methylfolate Formula 15
- Phenytoin Extended-Release Capsules-L-Methylfolate Formula 7.5
- Phenytoin Extended-Release Capsules-L-Methylfolate Forte
- Phenytoin Extended-Release Capsules-L-Methylfolate with B Vitamins
- Phenytoin Extended-Release Capsules-L-tryptophan