Life-sustaining therapy should not be withheld.

US FDA pregnancy category: Not assigned

Comments:
-Cyanide poisoning is a medical emergency that can be fatal for the pregnant person and fetus if untreated; use of this drug is recommended for known or suspected cyanide poisoning during pregnancy.
-There is no data on use in pregnant women to know this drugs risks, including the risk of fetal harm or reproductive effects.
-This drug produces methemoglobin.
-Fetal hemoglobin is more easily oxidized to methemoglobin than adult hemoglobin and fetal levels of methemoglobin reductase are lower than adults; if available, consider alternative therapies not associated with methemoglobinemia.
-Cyanide readily crosses the placenta; do not withhold because of concerns of the effect of this drug on the fetus.

There are no controlled data using any of the drugs, alone or in combination, 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) during gestation and throughout lactation showed severe anemia, reduced growth, a dose-related increase in postpartum mortality. A published study of treatment via drinking water at 2.6 times the maximum recommended daily dose from gestation days 7 to 8 did not show malformations or embryofetal or maternal toxicity. 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 fibre 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 oral doses between 400 and 580 mg/kg/day administered during organogenesis.

US FDA pregnancy category Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.

See references

Breastfeeding is not recommended.

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

Comments:
-There is no information regarding this drug on the presence in human milk, the effects on a breastfed infant, or effects on milk production.
-Cyanide and thiocyanate (formed when sodium thiocyanate combines with cyanide) are present in human milk.
-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