National Toxicology Program

National Toxicology Program
http://ntp.niehs.nih.gov/go/ts-10270-a

Testing Status of Primidone (primaclone) - 10270-A

 

CASRN: 125-33-7

Formula: C12-H14-N2-O2

Synonyms/Common Names

  • 5-Ethyldihydro-5-phenyl-4,6(1H,5H)-pyrimidinedione (9CI)

Known Uses

Prophylactic management of partial grand mal and psychomotor seizures that are refractory to other antiepileptic drugs.

Chemical Properties

Toxicity Effects (HSDB)

Short-Term Toxicity

  • 2 weeks (Dosed-Feed)  (C88035)  Completed 
    • Rats: F344/N; Mice: B6C3F1
    • Dose: R: 0, 0.125, 0.25, 0.5, 1.0, OR 2.0% M: 0, 0.0625, 0.125, 0.25, 0.5, OR 1.0% (5/SEX/SPECIES).
  • 13 weeks (Dosed-Feed)  (C88035)  Completed 
    • Rats: F344/N; Mice: B6C3F1
    • Dose: R&M: 0, 0.03, 0.06, 0.13, 0.25, OR 0.5% 20 RATS/SEX + 10 MICE/SEX.

Long-Term Carcinogenicity

  • 2 years (Dosed-Feed)  (C88035)  Report Complete 
    • TR-476 (NIH Number: 00-3966)  (Peer Review Approval 12/12/1996A )
      Toxicology and Carcinogenesis Studies of Primidone (CASRN 125-33-7) in F344/N Rats and B6C3F1 Mice (Feed Studies)
    • Rats: F344/N; Mice: B6C3F1
    • Carcinogenesis Results
      • Male Rats Equivocal Evidence 
      • Female Rats No Evidence 
      • Male Mice Clear Evidence 
      • Female Mice Clear Evidence 
    • Dose: M: 0, 0.03, 0.06, OR 0.13% R: 0, 0.06, 0.13, OR 0.25% (50/SEX/SPECIES).

Special Studies

  • Toxicokinetic Study (Gavage)  (S0560)  Completed 
    • Male and Female Rats: F344/N; Male and Female Mice: B6C3F1

Genetic Toxicology

  • In Vitro Cytogenetics (CA/SCE)  (945872)  Completed 
    • Sister Chromatid Exchange Negative 
    • Chromosome Aberrations Negative 
  • Micronucleus  (754198)  Completed 
    • Mice: B6C3F1
    • Male Negative 
  • Micronucleus  (A69181)  Completed 
    • Mice: B6C3F1
    • Male Negative 
    • Female Negative 
  • Salmonella  (323716)  Completed 
    • Citation: Mortelmans, K., Haworth, S., Lawlor, T., Speck, W., Tainer, B., and Zeiger, E. Salmonella mutagenicity tests. II. Results from the testing of 270 chemicals Environ. Mutagen. Vol. 8 (Suppl 7) (1986) 1-119
    •  Positive 

Organ Systems Toxicity

  • Continuous Breeding (Legacy) (Dosed-Feed)  (RACB90009)  Completed 
    • Citation: Final Report on the Reproductive Toxicity of Primaclone in CD-1 Swiss Mice
    • Mice: Swiss
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