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


VOL.: 24 (1980) (p. 163)

5. Summary of Data Reported and Evaluation

5.1 Experimental data

Phenazopyridine hydrochloride was tested in mice and rats by oral administration and in mice by intraperitoneal administration. After its oral administration in female mice, it significantly increased the incidence of hepatocellular adenomas and carcinomas. In male and female rats, it induced tumours of the colon and rectum.

Attention is drawn to the absence of studies on the mutagenicity or teratogenicity of this compound.

5.2 Human data

Phenazopyridine hydrochloride is a weak urinary-tract analgesic and is possibly antiseptic.

In one epidemiological study, involving a limited period of observation, no association was observed between use of phenazopyridine hydrochloride and any cancer.

5.3 Evaluation

There is sufficient evidence for the carcinogenicity of phenazopyridine hydrochloride in experimental animals. The available epidemiological data are insufficient to evaluate the carcinogenicity of phenazopyridine hydrochloride to humans. In the absence of adequate data in humans, phenazopyridine hydrochloride should be regarded, for practical purposes, as if it presented a carcinogenic risk to humans.

For definition of the italicized terms, see Preamble Evaluation.

Previous evaluation: Vol. 8 (1975)

Subsequent evaluation: Suppl. 7 (1987)

Last updated: 7 April 1998

    See Also:
       Toxicological Abbreviations