International Agency for Research on Cancer (IARC) - Summaries & Evaluations
VOL.: 24 (1980) (p. 259)
5. Summary of Data Reported and Evaluation
5.1 Experimental data
Spironolactone was tested by oral administration in two experiments in
rats. An increased incidence of thyroid and testicular tumours was
reported in one experiment but not in another experiment of longer
duration with lower doses.
Attention is drawn to the absence of studies on the teratogenicity and
mutagenicity of this compound.
5.2 Human data
Spironolactone is an aldosterone antagonist commonly used as a
Five cases of breast cancer were reported in women who had used a drug
containing spironolactone. Four analytical studies, however, showed
no consistent evidence of an association.
The experimental studies, while providing limited evidence of a
carcinogenic effect, were difficult to interpret because of
inadequacies and inconsistencies in reporting. Epidemiological studies
have not confirmed the suspicion raised by case reports that
spironolactone may cause breast cancer in humans. The data are
insufficient, however, to permit confident exclusion of such an
For definition of the italicized terms, see Preamble Evaluation.
Subsequent evaluations: Suppl. 7 (1987);
Vol. 79 (2001)
Last updated: 7 April 1998