Oral (male rat) LD₅₀ = 695 mg/kg MSDS.

Overdose

Symptoms of overdose include impairment of consciousness ranging from somnolence to light coma, in addition to cardiorespiratory collapse resulting in fatal outcomes have been reported ^{FDA label}.

Withdrawal effects

Following rapid decreases in dose or abrupt discontinuation of zolpidem and other sedative/hypnotics, reports of signs and symptoms similar to those associated with withdrawal from other CNS-depressant drugs have been made ^{FDA label}.

Carcinogenesis

Zolpidem was administered to rats and mice over a span of 2 years at dietary dosages of 4, 18, and 80 mg/kg/day. In mice, these doses are considered 26 to 520 times or 2 to 35 times the maximum 10 mg human dose, respectively. In rats, these doses are 43 to 876 times or 6 to 115 times the maximum 10 mg human dose. No evidence of carcinogenicity was seen in mice. Renal liposarcomas were observed in 4/100 rats (3 males, 1 female) receiving 80 mg/kg/day, and a renal lipoma was observed in one male rat at the 18 mg/kg/day dose. Incidence rates of lipoma and liposarcoma for zolpidem were similar to those seen in historical control cases, and the tumor findings are presumed to be a spontaneous occurrence, not causally related to zolpidem ^{FDA label}.

Mutagenesis

Zolpidem did not show mutagenic activity in several tests including the Ames test, genotoxicity in mouse lymphoma cells in vitro, chromosomal aberrations in cultured human lymphocytes, abnormal DNA synthesis in rat hepatocytes in vitro, and the micronucleus test performed in mice ^{FDA label}.

Impairment of fertility

In a rat reproduction study, the high dose (100 mg base/kg) of zolpidem lead to irregular estrus cycles and prolonged precoital intervals, however, there was no effect on male or female fertility after daily oral doses comparable to 5 to 130 times the recommended human dose. No effects on any other fertility parameters were observed ^{FDA label}.

Use in pregnancy

This drug is considered a pregnancy category C drug. There are currently no sufficient conclusive studies completed in pregnant women to determine the safety of zolpidem use during pregnancy. Zolpidem should be used during pregnancy only if the potential benefit outweighs the potential risk to the fetus.

Use in nursing

From 0.004% to 0.019% of the total administered zolpidem dose is excreted into milk. The effect of zolpidem on the nursing infant is unknown at this time. Caution should be observed when zolpidem is administered to a nursing mother ^{FDA label}.