COVID-19 is an emerging, rapidly evolving situation.

Get the latest public health information from CDC and research information from NIH.

U.S. flag

An official website of the United States government

Dot gov

The .gov means it's official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Share This:
Study Information
Study Attribute Value
CEBS Accession Number: 002-02663-0002-0000-1
Chemical Name: Phenazopyridine hydrochloride
CASRN: 136-40-3
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 693896_CA
Study Result: Positive

Study Result: Positive
Activation Trial Trial Call
No Activation  1  Questionable 
Induced Rat Liver S9  1_S9  Positive 

Trial #:1   Activation: No Activation    Date: 08/17/1982    Harvest Time: 26 hour(s)   Trial Call: Questionable   
  Dose
µg/mL		 Total
Cells Examined		 Total Aberrations Complex Aberrations Simple Aberrations Other Abs
No. of
Abs		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs
Vehicle Control: Negative (Not Specified) 
0         
 100 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Dimethyl Sulfoxide 
0         
 100 1 0.010 1.0 1 0.010 1.0 0 0.000 0.0 0 0.000 0.0
Test Chemical: Phenazopyridine hydrochloride 
20         
 0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 
30         
 87 15 0.172 7.0 3 0.034 3.0 11 0.126 5.0 1 0.011 1.0 
40         
 100 4 0.040 3.0 4 0.040 3.0 0 0.000 0.0 0 0.000 0.0 
60         
 100 1 0.010 1.0 1 0.010 1.0 0 0.000 0.0 0 0.000 0.0 
75         
 0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0 0 0.000 0.0
Positive Control: Mitomycin-C 
 0.063     
 50 13 0.260 22.0 6 0.120 10.0 6 0.120 12.0 1 0.020 2.0
Trend: 0.068 0.234 -0.250  
Probability: 0.473 0.408 0.599  


Trial #:1_S9   Activation: Induced Rat Liver S9    Date: 08/17/1982    Harvest Time: 26 hour(s)   Trial Call: Positive   
  Dose
µg/mL		 Total
Cells Examined		 Total Aberrations Complex Aberrations Simple Aberrations Other Abs
No. of
Abs		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs		 No. of
Abs.		 Abs
Per
Cell		 % Cells
With
Abs
Vehicle Control: Negative (Not Specified) 
0         
 100 2 0.020 2.0 2 0.020 2.0 0 0.000 0.0 0 0.000 0.0
Dimethyl Sulfoxide 
0         
 100 3 0.030 2.0 2 0.020 2.0 1 0.010 1.0 0 0.000 0.0
Test Chemical: Phenazopyridine hydrochloride 
105         
 50 25 0.500 34.0 13 0.260 18.0 4 0.080 8.0 8 0.160 16.0 
112.5       
 50 29 0.580 34.0 15 0.300 24.0 11 0.220 14.0 3 0.060 6.0 
120         
 50 87 1.740 46.0 23 0.460 24.0 17 0.340 20.0 47 0.940 94.0
Positive Control: Cyclophosphamide 
10         
 50 8 0.160 10.0 2 0.040 4.0 5 0.100 8.0 1 0.020 2.0
Trend: 6.281 4.229 4.135  
Probability: 0.000 0.000 0.000