Trimethoprim potentiates valproic acid-induced neural tube defects (NTDs) in mice. 1993

M M Elmazar, and H Nau
Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Egypt.

The antiepileptic drug valproic acid (VPA) may produce NTDs because of interference with folate metabolism. Therefore, the possible interactions of VPA with the dihydrofolate reductase inhibitor trimethoprim (TM) was investigated. The combination of TM with sulfamethoxazol is used for treatment of urinary infections, the most common complications of pregnancy. TM (80 and 160 mg/kg) was given i.p. and orally, 0.5 and 1 h, respectively, prior to valproic acid (VPA, 300 and 400 mg/kg, s.c.) in day 8 pregnant NMRI mice. Fetuses were examined for exencephaly, resorptions, and fetal weight retardation on day 18 of gestation. TM (160 mg/kg, i.p.) produced no exencephaly or embryolethality, but increased fetal weight. Administration of TM (80 mg/kg, i.p.) increased VPA-induced exencephaly and fetal weight retardation but not embryolethality. Exencephaly rates induced by VPA (300 and 400 mg/kg) were 4% and 12.9% and were increased by coadministration of TM to 22.7% and 42.5%, respectively (P < 0.01). Oral TM also increased VPA-induced exencephaly and fetal weight retardation but with lower potency than i.p. injection. The observed effects were not due to altered VPA pharmacokinetics. These results support the view that VPA-induced neural tube defects may be mediated via an interaction with folate metabolism, and advise against TM-use in VPA-treated epileptics during pregnancy.

UI MeSH Term Description Entries
D008297 Male Males
D008815 Mice, Inbred Strains Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations, or by parent x offspring matings carried out with certain restrictions. All animals within an inbred strain trace back to a common ancestor in the twentieth generation. Inbred Mouse Strains,Inbred Strain of Mice,Inbred Strain of Mouse,Inbred Strains of Mice,Mouse, Inbred Strain,Inbred Mouse Strain,Mouse Inbred Strain,Mouse Inbred Strains,Mouse Strain, Inbred,Mouse Strains, Inbred,Strain, Inbred Mouse,Strains, Inbred Mouse
D009436 Neural Tube Defects Congenital malformations of the central nervous system and adjacent structures related to defective neural tube closure during the first trimester of pregnancy generally occurring between days 18-29 of gestation. Ectodermal and mesodermal malformations (mainly involving the skull and vertebrae) may occur as a result of defects of neural tube closure. (From Joynt, Clinical Neurology, 1992, Ch55, pp31-41) Craniorachischisis,Developmental Defects, Neural Tube,Diastematomyelia,Exencephaly,Neurenteric Cyst,Spinal Cord Myelodysplasia,Tethered Cord Syndrome,Acrania,Developmental Neural Tube Defects,Iniencephaly,Neural Tube Developmental Defects,Neuroenteric Cyst,Occult Spinal Dysraphism,Occult Spinal Dysraphism Sequence,Tethered Spinal Cord Syndrome,Acranias,Craniorachischises,Cyst, Neurenteric,Cyst, Neuroenteric,Cysts, Neurenteric,Cysts, Neuroenteric,Defect, Neural Tube,Defects, Neural Tube,Diastematomyelias,Dysraphism, Occult Spinal,Dysraphisms, Occult Spinal,Exencephalies,Iniencephalies,Myelodysplasia, Spinal Cord,Myelodysplasias, Spinal Cord,Neural Tube Defect,Neurenteric Cysts,Neuroenteric Cysts,Occult Spinal Dysraphisms,Spinal Cord Myelodysplasias,Spinal Dysraphism, Occult,Spinal Dysraphisms, Occult,Tethered Cord Syndromes
D011247 Pregnancy The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH. Gestation,Pregnancies
D011248 Pregnancy Complications Conditions or pathological processes associated with pregnancy. They can occur during or after pregnancy, and range from minor discomforts to serious diseases that require medical interventions. They include diseases in pregnant females, and pregnancies in females with diseases. Adverse Birth Outcomes,Complications, Pregnancy,Adverse Birth Outcome,Birth Outcome, Adverse,Complication, Pregnancy,Outcome, Adverse Birth,Pregnancy Complication
D004357 Drug Synergism The action of a drug in promoting or enhancing the effectiveness of another drug. Drug Potentiation,Drug Augmentation,Augmentation, Drug,Augmentations, Drug,Drug Augmentations,Drug Potentiations,Drug Synergisms,Potentiation, Drug,Potentiations, Drug,Synergism, Drug,Synergisms, Drug
D005260 Female Females
D005492 Folic Acid A member of the vitamin B family that stimulates the hematopoietic system. It is present in the liver and kidney and is found in mushrooms, spinach, yeast, green leaves, and grasses (POACEAE). Folic acid is used in the treatment and prevention of folate deficiencies and megaloblastic anemia. Pteroylglutamic Acid,Vitamin M,Folacin,Folate,Folic Acid, (D)-Isomer,Folic Acid, (DL)-Isomer,Folic Acid, Calcium Salt (1:1),Folic Acid, Monopotassium Salt,Folic Acid, Monosodium Salt,Folic Acid, Potassium Salt,Folic Acid, Sodium Salt,Folvite,Vitamin B9,B9, Vitamin
D005493 Folic Acid Antagonists Inhibitors of the enzyme, dihydrofolate reductase (TETRAHYDROFOLATE DEHYDROGENASE), which converts dihydrofolate (FH2) to tetrahydrofolate (FH4). They are frequently used in cancer chemotherapy. (From AMA, Drug Evaluations Annual, 1994, p2033) Antifolate,Antifolates,Dihydrofolate Reductase Inhibitor,Folic Acid Antagonist,Dihydrofolate Reductase Inhibitors,Folic Acid Metabolism Inhibitors,Acid Antagonist, Folic,Acid Antagonists, Folic,Antagonist, Folic Acid,Antagonists, Folic Acid,Inhibitor, Dihydrofolate Reductase,Inhibitors, Dihydrofolate Reductase,Reductase Inhibitor, Dihydrofolate,Reductase Inhibitors, Dihydrofolate
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia

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