Nalidixic acid

Caution should be observed in patients with glucose-6-phosphate dehydrogenase deficiency.

Hemolytic anemia has been reported after oral administration of nalidixic acid, sometimes associated with glucose 6-phosphate dehydrogenase deficiency.

Pregnancy Category C.

Nalidixic acid has been shown to be teratogenic and embryocidal in rats when given in oral doses six times the human dose. Nalidixic acid also prolonged the duration of pregnancy especially at four times the clinical dose. There are no adequate and well-controlled studies in pregnant women. Since nalidixic acid, like other drugs in this class, causes arthropathy in immature animals, it should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Since nalidixic acid is excreted in breast milk, it is contraindicated during lactation.

In lifetime studies in the rat given nalidixic acid in the diet, there was an increased incidence of preputial gland neoplasms in the treated males and clitoral gland neoplasms in the treated females. Studies in mice in which nalidixic acid was administered in the feed for two years, or was given in the feed for 76 weeks followed by no treatment for 9 weeks, gave equivocal evidence of carcinogenic activity.

Nalidixic acid was tested in the Ames bacterial mutagenicity test (maximum dose 33 mcg/plate) and the mouse lymphoma assay (L5178Y/TK; maximum dose 100 mcg/mL) with and without metabolic activation, and results were negative.

Quinolones may cause dizziness and light-headedness, therefore, patients should know how they react to nalidixic acid before they operate an automobile or machinery or engage in activities requiring mental alertness or coordination.