International Agency for Research on Cancer (IARC) - Summaries & Evaluations

(Group 2B)

For definition of Groups, see Preamble Evaluation.

Supplement 7: (1987) (p. 312)

CAS No.: 136-40-3
Chem. Abstr. Name: 2,6-Pyridinediamine,3-(phenylazo)-,monohydrochloride

A. Evidence for carcinogenicity to humans (inadequate)

In one limited epidemiological study, no significant excess of any cancer was observed among 2214 patients who received phenazopyridine hydrochloride and were followed for a minimum of three years [ref: 1].

B. Evidence for carcinogenicity to animals (sufficient)

Oral administration of phenazopyridine hydrochloride increased the incidence of hepatocellular adenomas and carcinomas in female mice and induced tumours of the colon and rectum in rats [ref: 1].

C. Other relevant data

No data were available on the genetic and related effects of phenazopyridine hydrochloride in humans. It did not induce sex-linked recessive lethal mutations in Drosophila and was not mutagenic to bacteria [ref: 2].

Overall evaluation

Phenazopyridine hydrochloride is possibly carcinogenic to humans (Group 2B).

For definition of the italicized terms, see Preamble Evaluation.

Also see previous evaluations: Vol. 8 (1975); Vol. 24 (1980)


1. IARC Monographs, 24, 175-184, 1980

2. IARC Monographs, Suppl. 6, 451-452, 1987


Last updated: 3 March 1998

    See Also:
       Toxicological Abbreviations
       Phenazopyridine Hydrochloride (IARC Summary & Evaluation, Volume 8, 1975)