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Sodium nitrite / sodium thiosulfate Pregnancy and Breastfeeding Warnings

Sodium nitrite / sodium thiosulfate is also known as: Nithiodote

Medically reviewed by Last updated on Nov 23, 2020.

Sodium nitrite / sodium thiosulfate Pregnancy Warnings

This drug should not be used during pregnancy unless the benefit outweighs the risk to the fetus.

US FDA pregnancy category: C

There are no controlled data in human pregnancy.

Sodium nitrite: Animal studies did not show teratogenicity, however in one animal model treatment with 60 or 70 mg/kg/day resulted in abortion of the litters within 1 to 4 days of treatment. All animals given 70 mg/kg of sodium nitrite subcutaneously died within 60 minutes of treatment. Studies giving 60 mg/kg (about 1.7 times the recommended therapeutic dose) resulted in measurable blood methemoglobin levels in the dams and their fetuses for up to 6 hours post treatment, with maternal levels higher than fetal levels at all times measured. Treatment of pregnant animals via drinking water (2000 or 3000 mg/L of sodium nitrite, approximately 43 and 65 times the highest clinical dose) showed a dose-related increase in postpartum mortality. Animals exposed to sodium nitrite prenatally showed impaired discrimination learning behavior (both auditory and visual) and reduced long term retention of the passive avoidance response. Additional animal studies showed delayed development of AchE and 5-HT positive fiber ingrowth into the hippocampal dentate gyrus and parietal neocortex during the first week of life; these changes have been attributed to prenatal hypoxia from nitrite exposure. Two epidemiological studies report a statistically significant increase in congenital malformation (particularly in the CNS) risk associated with maternal consumption of water containing nitrate levels in excess of 5 ppm. A case control study suggests a non-statistically significant increase in the risk for CNS malformations with maternal nitrate consumption of 26 ppm or higher. Sodium nitrite produces methemoglobin. Fetal hemoglobin is oxidized to methemoglobin more easily than adult hemoglobin, and the fetus has lower methemoglobin reductase levels than adults; this suggests that a fetus would show greater sensitivity to methemoglobin leading to nitrite-induced prenatal hypoxia leading to retarded development of certain neurotransmitter systems in the brain and long lasting dysfunction.

Sodium thiosulfate: Animal studies did not show teratogenicity at doses comparable to those used in human cyanide poisoning; other studies suggest it ameliorates the teratogenic effects of cyanide poisoning. Animal studies have not shown embryotoxic or teratogenic effects at doses between 400 and 580 mg/kg/day. There are no reported epidemiological studies of congenital abnormalities in infants born to women treated with sodium thiosulfate during pregnancy.

US FDA pregnancy category C: Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.

See references

Sodium nitrite / sodium thiosulfate Breastfeeding Warnings

Caution is recommended.

Excreted into human milk: Unknown
Excreted into animal milk: Data not available

-Because this is used in life threatening situations, breastfeeding is not a contraindication.
-There is no data to say when breastfeeding may be safely restarted after administration of this drug.
-Animal studies using sodium nitrite in drinking water during pregnancy and lactation resulted in severe anemia, reduced growth, and increased mortality in the offspring.

See references

References for pregnancy information

  1. "Product Information. Nithiodote (sodium nitrite-sodium thiosulfate)." Hope Pharmaceuticals, Scottsdale, AZ.

References for breastfeeding information

  1. "Product Information. Nithiodote (sodium nitrite-sodium thiosulfate)." Hope Pharmaceuticals, Scottsdale, AZ.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.